@article{Bieri_du, title = {{No Title}} } @article{Agusti-Panareda2022, abstract = {The CO2 Human Emissions project has generated realistic high-resolution 9 km global simulations for atmospheric carbon tracers referred to as nature runs to foster carbon-cycle research applications with current and planned satellite missions, as well as the surge of in situ observations. Realistic atmospheric CO2, CH4 and CO fields can provide a reference for assessing the impact of proposed designs of new satellites and in situ networks and to study atmospheric variability of the tracers modulated by the weather. The simulations spanning 2015 are based on the Copernicus Atmosphere Monitoring Service forecasts at the European Centre for Medium Range Weather Forecasts, with improvements in various model components and input data such as anthropogenic emissions, in preparation of a CO2 Monitoring and Verification Support system. The relative contribution of different emissions and natural fluxes towards observed atmospheric variability is diagnosed by additional tagged tracers in the simulations. The evaluation of such high-resolution model simulations can be used to identify model deficiencies and guide further model improvements.}, author = {Agust{\'{i}}-Panareda, Anna and McNorton, Joe and Balsamo, Gianpaolo and Baier, Bianca C and Bousserez, Nicolas and Boussetta, Souhail and Brunner, Dominik and Chevallier, Fr{\'{e}}d{\'{e}}ric and Choulga, Margarita and Diamantakis, Michail and Engelen, Richard and Flemming, Johannes and Granier, Claire and Guevara, Marc and {Denier van der Gon}, Hugo and Elguindi, Nellie and Haussaire, Jean-Matthieu and Jung, Martin and Janssens-Maenhout, Greet and Kivi, Rigel and Massart, S{\'{e}}bastien and Papale, Dario and Parrington, Mark and Razinger, Miha and Sweeney, Colm and Vermeulen, Alex and Walther, Sophia}, doi = {10.1038/s41597-022-01228-2}, issn = {2052-4463}, journal = {Scientific Data}, number = {1}, pages = {160}, title = {{Global nature run data with realistic high-resolution carbon weather for the year of the Paris Agreement}}, url = {https://doi.org/10.1038/s41597-022-01228-2}, volume = {9}, year = {2022} } @article{acp-2022-156, author = {Ahlberg, E and Ausmeel, S and Nilsson, L and Spanne, M and Pauraite, J and Klen{\o}N{\o}jgaard, J and Bert{\`{o}}, M and Skov, H and Roldin, P and Kristensson, A and Swietlicki, E and Eriksson, A}, doi = {10.5194/acp-2022-156}, journal = {Atmospheric Chemistry and Physics Discussions}, pages = {1--20}, title = {{Measurement Report: Small effect of regional sources on black carbon properties and concentrations in Southern Sweden background air}}, url = {https://acp.copernicus.org/preprints/acp-2022-156/}, volume = {2022}, year = {2022} } @article{gmd-15-4739-2022, author = {Ala-K{\"{o}}nni, J and Kohonen, K.-M. and Lepp{\"{a}}ranta, M and Mammarella, I}, doi = {10.5194/gmd-15-4739-2022}, journal = {Geoscientific Model Development}, number = {12}, pages = {4739--4755}, title = {{Validation of turbulent heat transfer models against eddy covariance flux measurements over a seasonally ice-covered lake}}, url = {https://gmd.copernicus.org/articles/15/4739/2022/}, volume = {15}, year = {2022} } @article{f12020189, abstract = {Quantifying actual evapotranspiration (ETa) over natural vegetation is crucial in evaluating the water status of ecosystems and the water-use patterns in local or regional hydrological basins. Remote sensing-based surface energy balance models have been used extensively for estimating ETa in agro-environments; however, the application of these models to natural ecosystems is still limited. The surface energy balance algorithm for land (SEBAL) physical-based surface energy balance model was applied to estimate the actual evapotranspiration over a heterogeneous coverage of Mediterranean maquis in a natural reserve in Sardinia, Italy. The model was applied on 19 Landsat 5 and 8 images from 2009 to 2014, and the results were compared to the data of a micrometeorological station with eddy covariance flux measurements. Comparing the SEBAL-based evaporative fraction ($\Lambda$S) to the corresponding tower-derived evaporative fractions ($\Lambda$T) showed good flux estimations in the Landsat overpass time (Coefficient of determination R2 = 0.77, root mean square error RMSE = 0.05 and mean absolute error MAE = 0.076). Three methods were evaluated for upscaling instantaneous latent heat flux ($\lambda$E) to daily actual evapotranspiration (ETa,D). The upscaling methods use the evaporative fraction ($\Lambda$), the reference evapotranspiration fraction (EFr) and the ratio of daily to instantaneous incoming shortwave radiation (Rs24/Rsi) as upscaling factors under the hypothesis of diurnal self-preservation. A preliminary analysis performed using only in-situ measured data demonstrated that the three factors were relatively self-preserved during the daytime, and can yield good ETa,D estimations, particularly when obtained at near the Landsat scene acquisition time (≈10:00 UTC). The upscaling factors obtained from SEBAL retrieved instantaneous fluxes, and some ancillary measured meteorological data were used to upscale SEBAL-estimated instantaneous actual $\lambda$ to daily ET. The $\Lambda$ EFr and Rs24/Rsi methods on average overestimated the measured ETa,D by nearly 20, 61 and 18%, respectively. The performance of the $\Lambda$ and Rs24/Rsi methods was considered satisfactory, bearing in mind the high variable ground cover and the inherent variability of the biome composition, which cannot be properly represented in the Landsat moderate spatial resolution. In this study, we tested the potential of the SEBAL model application in a complex natural ecosystem. This modeling approach will be used to represent the spatial dynamics of ET, which will be integrated into further environmental and hydrological applications.}, author = {Awada, Hassan and {Di Prima}, Simone and Sirca, Costantino and Giadrossich, Filippo and Marras, Serena and Spano, Donatella and Pirastru, Mario}, doi = {10.3390/f12020189}, issn = {1999-4907}, journal = {Forests}, number = {2}, title = {{Daily Actual Evapotranspiration Estimation in a Mediterranean Ecosystem from Landsat Observations Using SEBAL Approach}}, url = {https://www.mdpi.com/1999-4907/12/2/189}, volume = {12}, year = {2021} } @article{BAO2022108708, abstract = {The sensitivity of photosynthesis to environmental changes is essential for understanding carbon cycle responses to global climate change and for the development of modeling approaches that explains its spatial and temporal variability. We collected a large variety of published sensitivity functions of gross primary productivity (GPP) to different forcing variables to assess the response of GPP to environmental factors. These include the responses of GPP to temperature; vapor pressure deficit, some of which include the response to atmospheric CO2 concentrations; soil water availability (W); light intensity; and cloudiness. These functions were combined in a full factorial light use efficiency (LUE) model structure, leading to a collection of 5600 distinct LUE models. Each model was optimized against daily GPP and evapotranspiration fluxes from 196 FLUXNET sites and ranked across sites based on a bootstrap approach. The GPP sensitivity to each environmental factor, including CO2 fertilization, was shown to be significant, and that none of the previously published model structures performed as well as the best model selected. From daily and weekly to monthly scales, the best model's median Nash-Sutcliffe model efficiency across sites was 0.73, 0.79 and 0.82, respectively, but poorer at annual scales (0.23), emphasizing the common limitation of current models in describing the interannual variability of GPP. Although the best global model did not match the local best model at each site, the selection was robust across ecosystem types. The contribution of light saturation and cloudiness to GPP was observed across all biomes (from 23% to 43%). Temperature and W dominates GPP and LUE but responses of GPP to temperature and W are lagged in cold and arid ecosystems, respectively. The findings of this study provide a foundation towards more robust LUE-based estimates of global GPP and may provide a benchmark for other empirical GPP products.}, author = {Bao, Shanning and Wutzler, Thomas and Koirala, Sujan and Cuntz, Matthias and Ibrom, Andreas and Besnard, Simon and Walther, Sophia and {\v{S}}igut, Ladislav and Moreno, Alvaro and Weber, Ulrich and Wohlfahrt, Georg and Cleverly, Jamie and Migliavacca, Mirco and Woodgate, William and Merbold, Lutz and Veenendaal, Elmar and Carvalhais, Nuno}, doi = {https://doi.org/10.1016/j.agrformet.2021.108708}, issn = {0168-1923}, journal = {Agricultural and Forest Meteorology}, keywords = { Diffuse fraction, Model comparison, Model equifinality, Radiation use efficiency, Randomly sampled sites, Sensitivity formulations, Temporal scales,Carbon assimilation}, pages = {108708}, title = {{Environment-sensitivity functions for gross primary productivity in light use efficiency models}}, url = {https://www.sciencedirect.com/science/article/pii/S0168192321003944}, volume = {312}, year = {2022} } @article{Belviso2022, abstract = {Carbonyl sulfide (COS) fluxes simulated by vegetation and soil component models, both implemented in the ORCHIDEE land surface model, were evaluated against field observations at two agroecosystems in central France. The dynamics of a biogenic process not yet accounted for by this model, i.e., COS emissions from croplands, was examined in the context of three independent and complementary approaches. First, during the growing seasons of 2019 and 2020, monthly variations in the nighttime ratio of vertical mole fraction gradients of COS and carbon dioxide measured between 5 and 180 m height (GradCOS/GradCO2), a proxy of the ratio of their respective nocturnal net fluxes, were monitored at a rural tall tower site near Orl{\'{e}}ans (i.e., a "profile vs. model" approach). Second, field observations of COS nocturnal fluxes, obtained by the Radon Tracer Method (RTM) at a sub-urban site near Paris, were used for that same purpose (i.e., a "RTM vs. model" approach of unaccounted biogenic emissions). This site has observations going back to 2014. Third, during the growing seasons of 2019, 2020 and 2021, horizontal mole fraction gradients of COS were calculated from downwind-upwind surveys of wheat and rapeseed crops as a proxy of their respective exchange rates at the plot scale (i.e., a "crop based" comparative approach). The "profile vs. model" approach suggests that the nocturnal net COS uptake gradually weakens during the peak growing season and recovers from August on. The "RTM vs. model" approach suggests that there exists a biogenic source of COS, the intensity of which culminates in late June early July. Our "crop based" comparative approach demonstrates that rapeseed crops shift from COS uptake to emission in early summer during the late stages of growth (ripening and senescence) while wheat crops uptake capacities lower markedly. Hence, rapeseed appears to be a much larger source of COS than wheat at the plot scale. Nevertheless, compared to current estimates of the largest COS sources (i.e., marine and anthropogenic emissions), agricultural emissions during the late stages of growth are of secondary importance.}, author = {Belviso, Sauveur and Abadie, Camille and Montagne, David and Hadjar, Dalila and Trop{\'{e}}e, Didier and Vialettes, Laurence and Kazan, Victor and Delmotte, Marc and Maignan, Fabienne and Remaud, Marine and Ramonet, Michel and Lopez, Morgan and Yver-Kwok, Camille and Ciais, Philippe}, doi = {10.1371/journal.pone.0278584}, file = {:Users/villekasurinen/Downloads/journal.pone.0278584.pdf:pdf}, isbn = {1111111111}, issn = {19326203}, journal = {PloS one}, number = {12}, pages = {e0278584}, pmid = {36472994}, title = {{Carbonyl sulfide (COS) emissions in two agroecosystems in central France}}, volume = {17}, year = {2022} } @article{acp-22-13243-2022, author = {Bergamaschi, P and Segers, A and Brunner, D and Haussaire, J.-M. and Henne, S and Ramonet, M and Arnold, T and Biermann, T and Chen, H and Conil, S and Delmotte, M and Forster, G and Frumau, A and Kubistin, D and Lan, X and Leuenberger, M and Lindauer, M and Lopez, M and Manca, G and M{\"{u}}ller-Williams, J and O'Doherty, S and Scheeren, B and Steinbacher, M and Trisolino, P and V\'\itkov{\'{a}}, G and {Yver Kwok}, C}, doi = {10.5194/acp-22-13243-2022}, journal = {Atmospheric Chemistry and Physics}, number = {20}, pages = {13243--13268}, title = {{High-resolution inverse modelling of European CH$_{4}$ emissions using the novel FLEXPART-COSMO TM5 4DVAR inverse modelling system}}, url = {https://acp.copernicus.org/articles/22/13243/2022/}, volume = {22}, year = {2022} } @article{Bhattacharjee2022, abstract = {We characterize the turbulent flow, using direct numerical simulations (DNS), within a closed channel between two parallel walls with a canopy of constant areal density profile on the lower wall. The canopy is modelled using different formulations of the Forchheimer drag, and the characteristic properties of the turbulent flows are compared. In particular, we examine the influence of the added drag on the mean profiles of the flow and the balance equations of the turbulent kinetic energy. We find that the different formulations of the drag strongly affect the mean and the turbulent profiles close to the canopy. We also observe the changes in the local anisotropy of the turbulent flow in the presence of the canopy. We find that there is an equal transfer of energy from the streamwise component to both the transverse components outside the canopy by the pressure and velocity-gradient correlation; inside the canopy, this correlation removes energy from both the streamwise and the wall-normal fluctuations and injects into the spanwise component. As a result, the energy content of the spanwise fluctuations is comparable to that of the streamwise components inside the canopy. Inside the canopy, we observe that the turbulent transport of Reynolds stresses acts as an important source of turbulent kinetic energy. The pressure-fluctuation transport plays a significant role inside the canopy close to the wall and is comparable to turbulent transport.}, author = {Bhattacharjee, Soumak and Mortikov, Evgeny and Debolskiy, Andrey and Kadantsev, Evgeny and Pandit, Rahul and Vesala, Timo and Sahoo, Ganapati}, doi = {10.1007/s10546-022-00731-8}, issn = {1573-1472}, journal = {Boundary-Layer Meteorology}, number = {2}, pages = {259--276}, title = {{Direct Numerical Simulation of a Turbulent Channel Flow with Forchheimer Drag}}, url = {https://doi.org/10.1007/s10546-022-00731-8}, volume = {185}, year = {2022} } @article{hess-26-5137-2022, author = {Boeing, F and Rakovec, O and Kumar, R and Samaniego, L and Schr{\"{o}}n, M and Hildebrandt, A and Rebmann, C and Thober, S and M{\"{u}}ller, S and Zacharias, S and Bogena, H and Schneider, K and Kiese, R and Attinger, S and Marx, A}, doi = {10.5194/hess-26-5137-2022}, journal = {Hydrology and Earth System Sciences}, number = {19}, pages = {5137--5161}, title = {{High-resolution drought simulations and comparison to soil moisture observations in Germany}}, url = {https://hess.copernicus.org/articles/26/5137/2022/}, volume = {26}, year = {2022} } @article{essd-14-1125-2022, author = {Bogena, H R and Schr{\"{o}}n, M and Jakobi, J and Ney, P and Zacharias, S and Andreasen, M and Baatz, R and Boorman, D and Duygu, M B and Eguibar-Gal{\'{a}}n, M A and Fersch, B and Franke, T and Geris, J and {Gonz{\'{a}}lez Sanchis}, M and Kerr, Y and Korf, T and Mengistu, Z and Mialon, A and Nasta, P and Nitychoruk, J and Pisinaras, V and Rasche, D and Rosolem, R and Said, H and Schattan, P and Zreda, M and Achleitner, S and Albentosa-Hern{\'{a}}ndez, E and Aky{\"{u}}rek, Z and Blume, T and del Campo, A and Canone, D and Dimitrova-Petrova, K and Evans, J G and Ferraris, S and Frances, F and Gisolo, D and G{\"{u}}ntner, A and Herrmann, F and Iwema, J and Jensen, K H and Kunstmann, H and Lid{\'{o}}n, A and Looms, M C and Oswald, S and Panagopoulos, A and Patil, A and Power, D and Rebmann, C and Romano, N and Scheiffele, L and Seneviratne, S and Weltin, G and Vereecken, H}, doi = {10.5194/essd-14-1125-2022}, journal = {Earth System Science Data}, number = {3}, pages = {1125--1151}, title = {{COSMOS-Europe: a European network of cosmic-ray neutron soil moisture sensors}}, url = {https://essd.copernicus.org/articles/14/1125/2022/}, volume = {14}, year = {2022} } @article{essd-14-743-2022, author = {Br{\"{u}}mmer, C and R{\"{u}}ffer, J J and Delorme, J.-P. and Wintjen, P and Schrader, F and Beudert, B and Schaap, M and Ammann, C}, doi = {10.5194/essd-14-743-2022}, journal = {Earth System Science Data}, number = {2}, pages = {743--761}, title = {{Reactive nitrogen fluxes over peatland and forest ecosystems using micrometeorological measurement techniques}}, url = {https://essd.copernicus.org/articles/14/743/2022/}, volume = {14}, year = {2022} } @article{acp-22-7557-2022, author = {Brunner, C and Brem, B T and {Collaud Coen}, M and Conen, F and Steinbacher, M and Gysel-Beer, M and Kanji, Z A}, doi = {10.5194/acp-22-7557-2022}, journal = {Atmospheric Chemistry and Physics}, number = {11}, pages = {7557--7573}, title = {{The diurnal and seasonal variability of ice-nucleating particles at the High Altitude Station Jungfraujoch (3580\,m\,a.s.l.), Switzerland}}, url = {https://acp.copernicus.org/articles/22/7557/2022/}, volume = {22}, year = {2022} } @article{acp-22-3433-2022, author = {Conen, F and Einbock, A and Mignani, C and H{\"{u}}glin, C}, doi = {10.5194/acp-22-3433-2022}, journal = {Atmospheric Chemistry and Physics}, number = {5}, pages = {3433--3444}, title = {{Measurement report: Ice-nucleating particles active $\ge -15$\,{\degree}C in free tropospheric air over western Europe}}, url = {https://acp.copernicus.org/articles/22/3433/2022/}, volume = {22}, year = {2022} } @article{https://doi.org/10.1029/2021RG000736, abstract = {Abstract Fossil fuel combustion, land use change and other human activities have increased the atmospheric carbon dioxide (CO2) abundance by about 50\% since the beginning of the industrial age. The atmospheric CO2 growth rates would have been much larger if natural sinks in the land biosphere and ocean had not removed over half of this anthropogenic CO2. As these CO2 emissions grew, uptake by the ocean increased in response to increases in atmospheric CO2 partial pressure (pCO2). On land, gross primary production also increased, but the dynamics of other key aspects of the land carbon cycle varied regionally. Over the past three decades, CO2 uptake by intact tropical humid forests declined, but these changes are offset by increased uptake across mid- and high-latitudes. While there have been substantial improvements in our ability to study the carbon cycle, measurement and modeling gaps still limit our understanding of the processes driving its evolution. Continued ship-based observations combined with expanded deployments of autonomous platforms are needed to quantify ocean-atmosphere fluxes and interior ocean carbon storage on policy-relevant spatial and temporal scales. There is also an urgent need for more comprehensive measurements of stocks, fluxes and atmospheric CO2 in humid tropical forests and across the Arctic and boreal regions, which are experiencing rapid change. Here, we review our understanding of the atmosphere, ocean, and land carbon cycles and their interactions, identify emerging measurement and modeling capabilities and gaps and the need for a sustainable, operational framework to ensure a scientific basis for carbon management.}, annote = {e2021RG000736 2021RG000736}, author = {Crisp, David and Dolman, Han and Tanhua, Toste and McKinley, Galen A and Hauck, Judith and Bastos, Ana and Sitch, Stephen and Eggleston, Simon and Aich, Valentin}, doi = {https://doi.org/10.1029/2021RG000736}, journal = {Reviews of Geophysics}, keywords = { anthropogenic emissions, carbon fluxes, carbon stocks,carbon cycle}, number = {2}, pages = {e2021RG000736}, title = {{How Well Do We Understand the Land-Ocean-Atmosphere Carbon Cycle?}}, url = {https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2021RG000736}, volume = {60}, year = {2022} } @article{10.1093/icesjms/fsac149, abstract = {The Observing Air–Sea Interactions Strategy (OASIS) is a new United Nations Decade of Ocean Science for Sustainable Development programme working to develop a practical, integrated approach for observing air–sea interactions globally for improved Earth system (including ecosystem) forecasts, CO2 uptake assessments called for by the Paris Agreement, and invaluable surface ocean information for decision makers. Our “Theory of Change” relies upon leveraged multi-disciplinary activities, partnerships, and capacity strengthening. Recommendations from \\>40 OceanObs'19 community papers and a series of workshops have been consolidated into three interlinked Grand Ideas for creating #1: a globally distributed network of mobile air–sea observing platforms built around an expanded array of long-term time-series stations; #2: a satellite network, with high spatial and temporal resolution, optimized for measuring air–sea fluxes; and #3: improved representation of air–sea coupling in a hierarchy of Earth system models. OASIS activities are organized across five Theme Teams: (1) Observing Network Design \\& Model Improvement; (2) Partnership \\& Capacity Strengthening; (3) UN Decade OASIS Actions; (4) Best Practices \\& Interoperability Experiments; and (5) Findable–Accessible–Interoperable–Reusable (FAIR) models, data, and OASIS products. Stakeholders, including researchers, are actively recruited to participate in Theme Teams to help promote a predicted, safe, clean, healthy, resilient, and productive ocean.}, annote = {fsac149}, author = {Cronin, M F and Swart, S and Marandino, C A and Anderson, C and Browne, P and Chen, S and Joubert, W R and Schuster, U and Venkatesan, R and Addey, C I and Alves, O and Ardhuin, F and Battle, S and Bourassa, M A and Chen, Z and Chory, M and Clayson, C and de Souza, R B and du Plessis, M and Edmondson, M and Edson, J B and Gille, S T and Hermes, J and Hormann, V and Josey, S A and Kurz, M and Lee, T and Maicu, F and Moustahfid, E H and Nicholson, S-A and Nyadjro, E S and Palter, J and Patterson, R G and Penny, S G and Pezzi, L P and Pinardi, N and {Reeves Eyre}, J E J and Rome, N and Subramanian, A C and Stienbarger, C and Steinhoff, T and Sutton, A J and Tomita, H and Wills, S M and Wilson, C and Yu, L}, doi = {10.1093/icesjms/fsac149}, issn = {1054-3139}, journal = {ICES Journal of Marine Science}, title = {{Developing an Observing Air–Sea Interactions Strategy (OASIS) for the global ocean}}, url = {https://doi.org/10.1093/icesjms/fsac149}, year = {2022} } @article{Curbelo-Hernandez2021, abstract = {The seasonal and spatial variability of the CO2 system parameters and CO2 air-sea exchange were studied in the Northeast Atlantic Ocean between the northwest African coastal upwelling and the oligotrophic open-ocean waters of the North Atlantic subtropical gyre. Data was collected aboard a volunteer observing ship from February 2019 to February 2020. The seasonal and spatial variability of CO2 fugacity in seawater (fCO2,sw) was strongly driven by the seasonal temperature variation, which increased with latitude and was lower throughout the year in coastal regions where the upwelling and offshore transport was more intense. The thermal to biological effect ratio (T/B) was approximately 2, with minimum values along the African coastline related to higher biological activity in the upwelled waters. The fCO2,sw increased from winter to summer by 11.84 ± 0.28 $\mu$atm°C−1 on the inter-island routes and by 11.71 ± 0.25 $\mu$atm°C−1 along the northwest African continental shelf. The seasonality of total inorganic carbon normalized to constant salinity of 36.7 (NCT) was studied throughout the region. The effect of biological processes and calcification/dissolution on NCT between February and October represented >90% of the reduction of inorganic carbon while air-sea exchange described <6%. The seasonality of air-sea CO2 exchange was controlled by temperature. The surface waters of the entire region acted as a CO2 sink during the cold months and as a CO2 source during the warm months. The Canary basin acted as a net sink of −0.26 ± 0.04 molC m−2 yr−1. The northwest African continental shelf behaved as a stronger sink at −0.48 ± 0.09 molC m−2 yr−1. The calculated average CO2 flux for the entire area was −2.65 ± 0.44 TgCO2 yr−1 (−0.72 ± 0.12 TgC yr−1).}, author = {Curbelo-Hern{\'{a}}ndez, D and Gonz{\'{a}}lez-D{\'{a}}vila, M and Gonz{\'{a}}lez, A G and Gonz{\'{a}}lez-Santana, D and Santana-Casiano, J M}, doi = {https://doi.org/10.1016/j.scitotenv.2021.145804}, issn = {0048-9697}, journal = {Science of The Total Environment}, keywords = {Air-sea CO exchange,CO system,Northeast Atlantic,Northwest African coastal upwelling,Surface ocean observation platform}, pages = {145804}, title = {{CO2 fluxes in the Northeast Atlantic Ocean based on measurements from a surface ocean observation platform}}, url = {https://www.sciencedirect.com/science/article/pii/S0048969721008718}, volume = {775}, year = {2021} } @article{10.3389/fmars.2021.745304, abstract = {The seasonal and spatial variability of the CO2 system and air-sea fluxes were studied in surface waters of the Strait of Gibraltar between February 2019 and March 2021. High-resolution data was collected by a surface ocean observation platform aboard a volunteer observing ship. The CO2 system was strongly influenced by temperature and salinity fluctuations forced by the seasonal and spatial variability in the depth of the Atlantic–Mediterranean Interface layer and by the tidal and wind-induced upwelling. The changes in seawater CO2 fugacity (fCO2,sw) and fluxes were mainly driven by temperature despite the significant influence of non-thermal processes in the southernmost part. The thermal to non-thermal effect ratio (T/B) reached maximum values in the northern section (>1.8) and minimum values in the southern section (<1.30). The fCO2,sw increased with temperature by 9.02 ± 1.99 $\mu$atm °C–1 (r2 = 0.86 and $\rho$ = 0.93) and 4.51 ± 1.66 $\mu$atm °C–1 (r2 = 0.48 and $\rho$ = 0.69) in the northern and southern sections, respectively. The annual cycle of total inorganic carbon normalized to a constant salinity of 36.7 (NCT) was assessed. Net community production processes described 93.5–95.6% of the total NCT change, while air-sea exchange and horizontal and vertical advection accounted for <4.6%. The fCO2,sw in the Strait of Gibraltar since 1999 has been fitted to an equation with an interannual trend of 2.35 ± 0.06 $\mu$atm year–1 and a standard error of estimate of ±12.8 $\mu$atm. The seasonality of the air-sea CO2 fluxes reported the behavior as a strong CO2 sink during the cold months and as a weak CO2 source during the warm months. Both the northern and the southern sections acted as a net CO2 sink of −0.82 and −1.01 mol C m–2 year–1, respectively. The calculated average CO2 flux for the entire area was −7.12 Gg CO2 year–1 (−1.94 Gg C year–1).}, author = {Curbelo-Hern{\'{a}}ndez, David and Santana-Casiano, J Magdalena and Gonz{\'{a}}lez, Aridane Gonz{\'{a}}lez and Gonz{\'{a}}lez-D{\'{a}}vila, Melchor}, doi = {10.3389/fmars.2021.745304}, file = {:Users/villekasurinen/Downloads/fmars-08-745304.pdf:pdf}, issn = {2296-7745}, journal = {Frontiers in Marine Science}, title = {{Air-Sea CO2 Exchange in the Strait of Gibraltar}}, url = {https://www.frontiersin.org/article/10.3389/fmars.2021.745304}, volume = {8}, year = {2021} } @article{Daghino2022, abstract = {Plants harbor in their external surfaces and internal tissues a highly diverse and finely structured microbial assembly, the microbiota. Each plant compartment usually represents a unique ecological niche hosting a distinct microbial community and niche differentiation, which may mirror distinct functions of a specialized microbiota, has been mainly investigated for bacteria. Far less is known for the fungal components of the plant-associated microbiota. Here, we applied a metabarcoding approach to describe the fungal assemblages in different organs of Vaccinium myrtillus plants (Ericaceae) collected in a subalpine meadow in North-West Italy, and identified specific taxa enriched in internal tissues of roots, stems, leaves and flowers. We also traced the distribution of some important fungi commonly associated with plants of the family Ericaceae, namely the ericoid mycorrhizal (ErM) fungi and the dark septate endophytes (DSE), both playing important roles in plant growth and health. Operational taxonomic units attributed to established ErM fungal species in the genus Hyaloscypha and to DSE species in the Phialocephala-Acephala applanata complex (PAC) were found in all the plant organs. Mycorrhizal fungi are thought to be strictly associated with the plant roots, and this first observation of ErM fungi in the above-ground organs of the host plant may be explained by the evolutionary closeness of ErM fungi in the genus Hyaloscypha with non mycorrhizal fungal endophytes. This is also witnessed by the closer similarities of the ErM fungal genomes with the genomes of plant endophytes than with those of other mycorrhizal fungi, such as arbuscular or ectomycorrhizal fungi.}, author = {Daghino, Stefania and Martino, Elena and Voyron, Samuele and Perotto, Silvia}, doi = {10.1038/s41598-022-15154-1}, issn = {2045-2322}, journal = {Scientific Reports}, number = {1}, pages = {11013}, title = {{Metabarcoding of fungal assemblages in Vaccinium myrtillus endosphere suggests colonization of above-ground organs by some ericoid mycorrhizal and DSE fungi}}, url = {https://doi.org/10.1038/s41598-022-15154-1}, volume = {12}, year = {2022} } @article{s22239143, abstract = {Cosmic ray neutron sensors (CRNS) are increasingly used to determine field-scale soil moisture (SM). Uncertainty of the CRNS-derived soil moisture strongly depends on the CRNS count rate subject to Poisson distribution. State-of-the-art CRNS signal processing averages neutron counts over many hours, thereby accounting for soil moisture temporal dynamics at the daily but not sub-daily time scale. This study demonstrates CRNS signal processing methods to improve the temporal accuracy of the signal in order to observe sub-daily changes in soil moisture and improve the signal-to-noise ratio overall. In particular, this study investigates the effectiveness of the Moving Average (MA), Median filter (MF), Savitzky–Golay (SG) filter, and Kalman filter (KF) to reduce neutron count error while ensuring that the temporal SM dynamics are as good as possible. The study uses synthetic data from four stations for measuring forest ecosystem–atmosphere relations in Africa (Gorigo) and Europe (SMEAR II (Station for Measuring Forest Ecosystem–Atmosphere Relations), Rollesbroich, and Conde) with different soil properties, land cover and climate. The results showed that smaller window sizes (12 h) for MA, MF and SG captured sharp changes closely. Longer window sizes were more beneficial in the case of moderate soil moisture variations during long time periods. For MA, MF and SG, optimal window sizes were identified and varied by count rate and climate, i.e., estimated temporal soil moisture dynamics by providing a compromise between monitoring sharp changes and reducing the effects of outliers. The optimal window for these filters and the Kalman filter always outperformed the standard procedure of simple 24-h averaging. The Kalman filter showed its highest robustness in uncertainty reduction at three different locations, and it maintained relevant sharp changes in the neutron counts without the need to identify the optimal window size. Importantly, standard corrections of CRNS before filtering improved soil moisture accuracy for all filters. We anticipate the improved signal-to-noise ratio to benefit CRNS applications such as detection of rain events at sub-daily resolution, provision of SM at the exact time of a satellite overpass, and irrigation applications.}, author = {Davies, Patrick and Baatz, Roland and Bogena, Heye Reemt and Quansah, Emmanuel and Amekudzi, Leonard Kofitse}, doi = {10.3390/s22239143}, issn = {1424-8220}, journal = {Sensors}, number = {23}, title = {{Optimal Temporal Filtering of the Cosmic-Ray Neutron Signal to Reduce Soil Moisture Uncertainty}}, url = {https://www.mdpi.com/1424-8220/22/23/9143}, volume = {22}, year = {2022} } @article{https://doi.org/10.1029/2021GB007055, abstract = {Abstract About a quarter of the total anthropogenic CO2 emissions during the industrial era has been absorbed by the ocean. The rate limiting step for this uptake is the transport of the anthropogenic carbon (Cant) from the ocean mixed layer where it is absorbed to the interior ocean where it is stored. While it is generally known that deep water formation sites are important for vertical carbon transport, the exact magnitude of the fluxes across the base of the mixed layer in different regions is uncertain. Here, we determine where, when, and how much Cant has been injected across the mixed-layer base and into the interior ocean since the start of the industrialized era. We do this by combining a transport matrix derived from observations with a time-evolving boundary condition obtained from already published estimates of ocean Cant. Our results show that most of the Cant stored below the mixed layer are injected in the subtropics (40.1\%) and the Southern Ocean (36.0\%), while the Subpolar North Atlantic has the largest fluxes. The Subpolar North Atlantic is also the most important region for injecting Cant into the deep ocean with 81.6\% of the Cant reaching depths greater than 1,000 m. The subtropics, on the other hand, have been the most efficient in transporting Cant across the mixed-layer base per volume of water ventilated. This study shows how the oceanic Cant uptake relies on vertical transports in a few oceanic regions and sheds light on the pathways that fill the ocean Cant reservoir.}, annote = {e2021GB007055 2021GB007055}, author = {Davila, Xabier and Gebbie, Geoffrey and Brakstad, Ailin and Lauvset, Siv K and McDonagh, Elaine L and Schwinger, J{\"{o}}rg and Olsen, Are}, doi = {https://doi.org/10.1029/2021GB007055}, journal = {Global Biogeochemical Cycles}, keywords = { fluxes, mixed-layer, observations, transport matrix,anthropogenic carbon}, number = {5}, pages = {e2021GB007055}, title = {{How Is the Ocean Anthropogenic Carbon Reservoir Filled?}}, url = {https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2021GB007055}, volume = {36}, year = {2022} } @article{rs14112642, abstract = {Climate change amplifies the intensity and occurrence of dry periods leading to drought stress in vegetation. For monitoring vegetation stresses, sun-induced chlorophyll fluorescence (SIF) observations are a potential game-changer, as the SIF emission is mechanistically coupled to photosynthetic activity. Yet, the benefit of SIF for drought stress monitoring is not yet understood. This paper analyses the impact of drought stress on canopy-scale SIF emission and surface reflectance over a lettuce and mustard stand with continuous field spectrometer measurements. Here, the SIF measurements are linked to the plant’s photosynthetic efficiency, whereas the surface reflectance can be used to monitor the canopy structure. The mustard canopy showed a reduction in the biochemical component of its SIF emission (the fluorescence emission efficiency at 760 nm—ϵ760) as a reaction to drought stress, whereas its structural component (the Fluorescence Correction Vegetation Index—FCVI) barely showed a reaction. The lettuce canopy showed both an increase in the variability of its surface reflectance at a sub-daily scale and a decrease in ϵ760 during a drought stress event. These reactions occurred simultaneously, suggesting that sun-induced chlorophyll fluorescence and reflectance-based indices sensitive to the canopy structure provide complementary information. The intensity of these reactions depend on both the soil water availability and the atmospheric water demand. This paper highlights the potential for SIF from the upcoming FLuorescence EXplorer (FLEX) satellite to provide a unique insight on the plant’s water status. At the same time, data on the canopy reflectance with a sub-daily temporal resolution are a promising additional stress indicator for certain species.}, author = {{De Canni{\`{e}}re}, Simon and Vereecken, Harry and Defourny, Pierre and Jonard, Fran{\c{c}}ois}, doi = {10.3390/rs14112642}, issn = {2072-4292}, journal = {Remote Sensing}, number = {11}, title = {{Remote Sensing of Instantaneous Drought Stress at Canopy Level Using Sun-Induced Chlorophyll Fluorescence and Canopy Reflectance}}, url = {https://www.mdpi.com/2072-4292/14/11/2642}, volume = {14}, year = {2022} } @article{Demol2021a, abstract = {Quantifying the Earth's forest above-ground biomass (AGB) is indispensable for effective climate action and developing forest policy. Yet, current allometric scaling models (ASMs) to estimate AGB suffer several drawbacks related to model selection and uncertainties about calibration data traceability. Terrestrial laser scanning (TLS) offers a promising non-destructive alternative. Tree volume is reconstructed from TLS point clouds with quantitative structure models (QSMs) and converted to AGB with wood basic density. Earlier studies have found overall TLS-derived forest volume estimates to be accurate, but highlighted problems for reconstructing finer branches. Our objective was to evaluate TLS for estimating tree volumes by comparison with reference volumes and volumes from ASMs.We quantified the woody volume of 65 trees in Belgium (from 77 to 2800 L; Pinus sylvestris, Fagus sylvatica, Larix decidua, and Fraxinus excelsior) with QSMs and destructive reference measurements. We tested a volume expansion factor (VEF) approach by multiplying the solid and merchantable volume from QSMs by literature VEF values.Stem volume was reliably estimated with TLS. Total volume was overestimated by +21 % using original QSMs, by +9 % and –12 % using two sets of VEF-augmented QSMs, and by –7.3 % using best-available ASMs. The most accurate method differed per site, and the prediction errors for each method varied considerably between sites.VEF-augmented QSMs were only slightly better than original QSMs for estimating tree volume for common species in temperate forests. Despite satisfying estimates with ASMs, the model choice was a large source of uncertainty, and species-specific models did not always exist. Therefore, we advocate for further improving tree volume reconstructions with QSMs, especially for fine branches, instead of collecting more ground-truth data to calibrate VEF and allometric models. Promising developments such as improved co-registration and smarter filtering approaches are ongoing to further constrain volumetric errors in TLS-derived estimates.}, author = {Demol, Miro and Calders, Kim and Verbeeck, Hans and Gielen, Bert}, doi = {10.1093/aob/mcab110}, issn = {0305-7364}, journal = {Annals of Botany}, month = {nov}, number = {6}, pages = {805--819}, title = {{Forest above-ground volume assessments with terrestrial laser scanning: a ground-truth validation experiment in temperate, managed forests}}, url = {https://doi.org/10.1093/aob/mcab110}, volume = {128}, year = {2021} } @article{DORODNIKOV2022150457, abstract = {In-vitro incubation of environmental samples is a common approach to estimate CH4 oxidation potential. Here we developed and verified an in-situ method utilizing passive diffusion chambers (PDC, silicone tubes) to deliver 13C-labeled CH4 into peat for the determination of the CH4 oxidation potential based on 13C excess of CO2. To target CH4 oxidation under semi-aerobic and anaerobic conditions, we installed 20 PDCs (30 ml volume) below the water table in profiles from 35-cm to 2-m depths of a peatland in north-eastern Sweden in July 2017 using a peat auger. 13C-labeled CH4 was injected into PDCs through tubing twice during 12 days (day 0 and 6) and samples were collected at days 1, 3, 6, 8 and 11. Background (non-labeled) $\delta$13C of CO2 ranged from −7.3 (35 cm) to +5.7‰ (200 cm) with depth. These $\delta$13C values rose to +110 and + 204‰ after the CH4 injection. The estimated CH4-derived C in CO2 was the lowest at the bottom of the profile (0.3 $\mu$mol L−1), whereas the maximum was at 100 cm (6.1 $\mu$mol L−1) at five days after the second labeling. This corresponded to 1.5–7.2% of the total CH4 pool to be oxidized, depending on depth. This novel approach with belowground in-situ 13C labeling of gases demonstrated the suitability of tracing the transformations of these gases in soil depth by PDCs and for the first time verified the in-situ occurrence of a deep-peat CH4 oxidation.}, author = {Dorodnikov, Maxim and Knorr, Klaus-Holger and Fan, Lichao and Kuzyakov, Yakov and Nilsson, Mats B}, doi = {https://doi.org/10.1016/j.scitotenv.2021.150457}, issn = {0048-9697}, journal = {Science of The Total Environment}, keywords = { CH oxidation, Greenhouse gases, In-situ labeling, Passive diffusion chamber, Peatland,Methane}, pages = {150457}, title = {{A novel belowground in-situ gas labeling approach: CH4 oxidation in deep peat using passive diffusion chambers and 13C excess}}, url = {https://www.sciencedirect.com/science/article/pii/S0048969721055340}, volume = {806}, year = {2022} } @article{essd-2022-114, author = {Erdbr{\"{u}}gger, J and van Meerveld, I and Seibert, J and Bishop, K}, doi = {10.5194/essd-2022-114}, journal = {Earth System Science Data Discussions}, pages = {1--40}, title = {{Shallow groundwater level time series and a groundwater chemistry survey from a boreal headwater catchment}}, url = {https://essd.copernicus.org/preprints/essd-2022-114/}, volume = {2022}, year = {2022} } @article{ErikssonStenstrom2022, abstract = {The European Spallation Source (ESS) is a neutron-based research facility under construction in Lund in southern Sweden. The spallation reactions will generate not only the desired neutrons, but also many radioactive by-products, including 14C. As part of the licensing process, and as recommended by the IAEA, various preoperational studies are being carried out, including mapping the “zero-point” radiation environment around the site. As the city of Lund hosts several facilities using 14C-labeled substances, and since temporary and local 14C contamination have been observed in the past, 14C mapping is an important part of these baseline assessments. We here present a summary of 14C levels in various terrestrial environmental samples in Lund and in southern Sweden during the years 2012 to 2020. These environmental F14C do not display significantly elevated levels compared to sites located remote from Lund. We also describe a local 14C contamination event that was detected at the Lund Radiocarbon Dating Laboratory in 2009. Horse-chestnut leaves collected close to the laboratory exhibited F14C values of up to ∼25% above the clean air background. Elevated values of F14C were also found in a short tree-ring series, especially in 2007. The source of this contamination was identified and successfully removed.}, author = {{Eriksson Stenstr{\"{o}}m}, Kristina and Skog, G{\"{o}}ran and Bernhardsson, Christian and Mattsson, S{\"{o}}ren and Nielsen, Anne Birgitte and Rundgren, Mats and Muscheler, Raimund and Linderson, Hans and P{\'{e}}dehontaa-Hiaa, Guillaume and R{\"{a}}{\"{a}}f, Christopher}, doi = {10.1017/RDC.2022.2}, file = {:Users/villekasurinen/Downloads/environmental-levels-of-radiocarbon-in-lund-sweden-prior-to-the-start-of-the-european-spallation-source.pdf:pdf}, issn = {00338222}, journal = {Radiocarbon}, keywords = {contamination,environment,preoperational assessments}, number = {1}, pages = {51--67}, title = {{Environmental Levels of Radiocarbon in Lund, Sweden, Prior To the Start of the European Spallation Source}}, volume = {64}, year = {2022} } @article{Etzold2022, abstract = {Abstract Radial stem growth dynamics at seasonal resolution are essential to understand how forests respond to climate change. We studied daily radial growth of 160 individuals of seven temperate tree species at 47 sites across Switzerland over 8 years. Growth of all species peaked in the early part of the growth season and commenced shortly before the summer solstice, but with species-specific seasonal patterns. Day length set a window of opportunity for radial growth. Within this window, the probability of daily growth was constrained particularly by air and soil moisture, resulting in intermittent growth to occur only on 29 to 77 days (30% to 80%) within the growth period. The number of days with growth largely determined annual growth, whereas the growth period length contributed less. We call for accounting for these non-linear intra-annual and species-specific growth dynamics in tree and forest models to reduce uncertainties in predictions under climate change.}, annote = {https://doi.org/10.1111/ele.13933}, author = {Etzold, Sophia and Sterck, Frank and Bose, Arun K and Braun, Sabine and Buchmann, Nina and Eugster, Werner and Gessler, Arthur and Kahmen, Ansgar and Peters, Richard L and Vitasse, Yann and Walthert, Lorenz and Ziemi{\'{n}}ska, Kasia and Zweifel, Roman}, doi = {https://doi.org/10.1111/ele.13933}, issn = {1461-023X}, journal = {Ecology Letters}, keywords = {TreeNet,dendrometer,intra-annual growth,phenology,seasonality,soil water potential,tree growth,vapour pressure deficit}, month = {feb}, number = {2}, pages = {427--439}, publisher = {John Wiley & Sons, Ltd}, title = {{Number of growth days and not length of the growth period determines radial stem growth of temperate trees}}, url = {https://doi.org/10.1111/ele.13933}, volume = {25}, year = {2022} } @article{Foken2021, abstract = {Extensive studies are available that analyse time series of carbon dioxide and water flux measurements of FLUXNET sites over many years and link these results to climate change such as changes in atmospheric carbon dioxide concentration, air temperature and growing season length and other factors. Many of the sites show trends to a larger carbon uptake. Here we analyse time series of net ecosystem exchange, gross primary production, respiration, and evapotranspiration of four forest sites with particularly long measurement periods of about 20 years. The regular trends shown are interrupted by periods with higher or lower increases of carbon uptake. These breakpoints can be of very different origin and include forest decline, increased vegetation period, drought effects, heat waves, and changes in site heterogeneity. The influence of such breakpoints should be included in long-term studies of land-atmosphere exchange processes.}, author = {Foken, Thomas and Babel, Wolfgang and Munger, J. William and Gr{\"{o}}nholm, Tiia and Vesala, Timo and Knohl, Alexander}, doi = {10.1080/16000889.2021.1915648}, file = {:Users/villekasurinen/Downloads/46-209-1-SM.pdf:pdf}, issn = {16000889}, journal = {Tellus, Series B: Chemical and Physical Meteorology}, keywords = {breakpoints,carbon uptake,climate change,eddy-covariance,forest}, number = {1}, pages = {1--12}, publisher = {Taylor & Francis}, title = {{Selected breakpoints of net forest carbon uptake at four eddy-covariance sites}}, url = {https://doi.org/10.1080/16000889.2021.1915648}, volume = {73}, year = {2021} } @article{essd-14-4811-2022, author = {Friedlingstein, P and O'Sullivan, M and Jones, M W and Andrew, R M and Gregor, L and Hauck, J and {Le Qu{\'{e}}r{\'{e}}}, C and Luijkx, I T and Olsen, A and Peters, G P and Peters, W and Pongratz, J and Schwingshackl, C and Sitch, S and Canadell, J G and Ciais, P and Jackson, R B and Alin, S R and Alkama, R and Arneth, A and Arora, V K and Bates, N R and Becker, M and Bellouin, N and Bittig, H C and Bopp, L and Chevallier, F and Chini, L P and Cronin, M and Evans, W and Falk, S and Feely, R A and Gasser, T and Gehlen, M and Gkritzalis, T and Gloege, L and Grassi, G and Gruber, N and G{\"{u}}rses, {\"{O}} and Harris, I and Hefner, M and Houghton, R A and Hurtt, G C and Iida, Y and Ilyina, T and Jain, A K and Jersild, A and Kadono, K and Kato, E and Kennedy, D and {Klein Goldewijk}, K and Knauer, J and Korsbakken, J I and Landsch{\"{u}}tzer, P and Lef{\`{e}}vre, N and Lindsay, K and Liu, J and Liu, Z and Marland, G and Mayot, N and McGrath, M J and Metzl, N and Monacci, N M and Munro, D R and Nakaoka, S.-I. and Niwa, Y and O'Brien, K and Ono, T and Palmer, P I and Pan, N and Pierrot, D and Pocock, K and Poulter, B and Resplandy, L and Robertson, E and R{\"{o}}denbeck, C and Rodriguez, C and Rosan, T M and Schwinger, J and S{\'{e}}f{\'{e}}rian, R and Shutler, J D and Skjelvan, I and Steinhoff, T and Sun, Q and Sutton, A J and Sweeney, C and Takao, S and Tanhua, T and Tans, P P and Tian, X and Tian, H and Tilbrook, B and Tsujino, H and Tubiello, F and van der Werf, G R and Walker, A P and Wanninkhof, R and Whitehead, C and {Willstrand Wranne}, A and Wright, R and Yuan, W and Yue, C and Yue, X and Zaehle, S and Zeng, J and Zheng, B}, doi = {10.5194/essd-14-4811-2022}, journal = {Earth System Science Data}, number = {11}, pages = {4811--4900}, title = {{Global Carbon Budget 2022}}, url = {https://essd.copernicus.org/articles/14/4811/2022/}, volume = {14}, year = {2022} } @article{Fu2022, abstract = {Abstract Understanding the critical soil moisture (SM) threshold (?crit) of plant water stress and land surface energy partitioning is a basis to evaluate drought impacts and improve models for predicting future ecosystem condition and climate. Quantifying the ?crit across biomes and climates is challenging because observations of surface energy fluxes and SM remain sparse. Here, we used the latest database of eddy covariance measurements to estimate ?crit across Europe by evaluating evaporative fraction (EF)-SM relationships and investigating the covariance between vapor pressure deficit (VPD) and gross primary production (GPP) during SM dry-down periods. We found that the ?crit and soil matric potential threshold in Europe are 16.5% and ?0.7 MPa, respectively. Surface energy partitioning characteristics varied among different vegetation types; EF in savannas had the highest sensitivities to SM in water-limited stage, and the lowest in forests. The sign of the covariance between daily VPD and GPP consistently changed from positive to negative during dry-down across all sites when EF shifted from relatively high to low values. This sign of the covariance changed after longer period of SM decline in forests than in grasslands and savannas. Estimated ?crit from the VPD?GPP covariance method match well with the EF?SM method, showing this covariance method can be used to detect the ?crit. We further found that soil texture dominates the spatial variability of ?crit while shortwave radiation and VPD are the major drivers in determining the spatial pattern of EF sensitivities. Our results highlight for the first time that the sign change of the covariance between daily VPD and GPP can be used as an indicator of how ecosystems transition from energy to SM limitation. We also characterized the corresponding ?crit and its drivers across diverse ecosystems in Europe, an essential variable to improve the representation of water stress in land surface models.}, annote = {https://doi.org/10.1111/gcb.16050}, author = {Fu, Zheng and Ciais, Philippe and Makowski, David and Bastos, Ana and Stoy, Paul C and Ibrom, Andreas and Knohl, Alexander and Migliavacca, Mirco and Cuntz, Matthias and {\v{S}}igut, Ladislav and Peichl, Matthias and Loustau, Denis and El-Madany, Tarek S and Buchmann, Nina and Gharun, Mana and Janssens, Ivan and Markwitz, Christian and Gr{\"{u}}nwald, Thomas and Rebmann, Corinna and M{\"{o}}lder, Meelis and Varlagin, Andrej and Mammarella, Ivan and Kolari, Pasi and Bernhofer, Christian and Heliasz, Michal and Vincke, Caroline and Pitacco, Andrea and Cremonese, Edoardo and Folt{\'{y}}nov{\'{a}}, Lenka and Wigneron, Jean-Pierre}, doi = {https://doi.org/10.1111/gcb.16050}, issn = {1354-1013}, journal = {Global Change Biology}, keywords = {Europe,critical soil moisture threshold,drought,evaporative fraction,gross primary production,surface energy partitioning,vapor pressure deficit}, month = {mar}, number = {6}, pages = {2111--2123}, publisher = {John Wiley & Sons, Ltd}, title = {{Uncovering the critical soil moisture thresholds of plant water stress for European ecosystems}}, url = {https://doi.org/10.1111/gcb.16050}, volume = {28}, year = {2022} } @article{Fu2022a, abstract = {Both low soil water content (SWC) and high atmospheric dryness (vapor pressure deficit, VPD) can negatively affect terrestrial gross primary production (GPP). The sensitivity of GPP to soil versus atmospheric dryness is difficult to disentangle, however, because of their covariation. Using global eddy-covariance observations, here we show that a decrease in SWC is not universally associated with GPP reduction. GPP increases in response to decreasing SWC when SWC is high and decreases only when SWC is below a threshold. By contrast, the sensitivity of GPP to an increase of VPD is always negative across the full SWC range. We further find canopy conductance decreases with increasing VPD (irrespective of SWC), and with decreasing SWC on drier soils. Maximum photosynthetic assimilation rate has negative sensitivity to VPD, and a positive sensitivity to decreasing SWC when SWC is high. Earth System Models underestimate the negative effect of VPD and the positive effect of SWC on GPP such that they should underestimate the GPP reduction due to increasing VPD in future climates.}, author = {Fu, Zheng and Ciais, Philippe and Prentice, I. Colin and Gentine, Pierre and Makowski, David and Bastos, Ana and Luo, Xiangzhong and Green, Julia K. and Stoy, Paul C. and Yang, Hui and Hajima, Tomohiro}, doi = {10.1038/s41467-022-28652-7}, file = {:Users/villekasurinen/Downloads/s41467-022-28652-7.pdf:pdf}, issn = {20411723}, journal = {Nature Communications}, number = {1}, pages = {1--10}, pmid = {35190562}, publisher = {Springer US}, title = {{Atmospheric dryness reduces photosynthesis along a large range of soil water deficits}}, volume = {13}, year = {2022} } @inproceedings{10.1117/12.2636335, author = {Ganeva, Dessislava and Chanev, Milen and Filchev, Lachezar and Jelev, Georgi and Valcheva, Darina}, booktitle = {Remote Sensing for Agriculture, Ecosystems, and Hydrology XXIV}, doi = {10.1117/12.2636335}, editor = {Neale, Christopher M U and Maltese, Antonino}, keywords = { In-situ phenophases, Land Surface Phenology, Phenocam, Phenological indicators, Time series analysis,Harmonized Landsat-8 and Sentinel-2}, organization = {International Society for Optics and Photonics}, pages = {1226208}, publisher = {SPIE}, title = {{Evaluation of PhenoCam phenology of barley}}, url = {https://doi.org/10.1117/12.2636335}, volume = {12262}, year = {2022} } @article{bg-19-5645-2022, author = {Guti{\'{e}}rrez-Loza, L and Nilsson, E and Wallin, M B and Sahl{\'{e}}e, E and Rutgersson, A}, doi = {10.5194/bg-19-5645-2022}, journal = {Biogeosciences}, number = {24}, pages = {5645--5665}, title = {{On physical mechanisms enhancing air--sea CO$_2$ exchange}}, url = {https://bg.copernicus.org/articles/19/5645/2022/}, volume = {19}, year = {2022} } @article{https://doi.org/10.1111/plb.13455, abstract = {Abstract The occurrence of hot drought, i.e. low water availability and simultaneous high air temperature, represents a severe threat to ecosystems. Here, we investigated how the 2018 hot drought in Central Europe caused a tipping point in tree and ecosystem functioning in a Scots pine (Pinus sylvestris L.) forest in southwest Germany. Measurements of stress indicators, such as needle water potential, carbon assimilation and volatile organic compound (VOC) emissions, of dominant P. sylvestris trees were deployed to evaluate tree functioning during hot drought. Ecosystem impact and recovery were assessed as ecosystem carbon exchange, normalized difference vegetation index (NDVI) from satellite data and tree mortality data. During summer 2018, needle water potentials of trees dropped to minimum values of −7.5 ± 0.2 MPa, which implied severe hydraulic impairment of P. sylvestris. Likewise, carbon assimilation and VOC emissions strongly declined after mid-July. Decreasing NDVI values from August 2018 onwards were detected, along with severe defoliation in P. sylvestris, impairing ecosystem carbon flux recovery in 2019, shifting the forest into a year-round carbon source. A total of 47\% of all monitored trees (n = 368) died by September 2020. NDVI recovered to pre-2018 levels in 2019, likely caused by emerging broadleaved understorey species. The 2018 hot drought had severe negative impacts on P. sylvestris. The co-occurrence of unfavourable site-specific conditions with recurrent severe droughts resulted in accelerated mortality. Thus, the 2018 hot drought pushed the P. sylvestris stand towards its tipping point, with a subsequent vegetation shift to a broadleaf-dominated forest.}, author = {Haberstroh, S and Werner, C and Gr{\"{u}}n, M and Kreuzwieser, J and Seifert, T and Schindler, D and Christen, A}, doi = {https://doi.org/10.1111/plb.13455}, journal = {Plant Biology}, keywords = { NDVI, Net ecosystem exchange, Pinus sylvestris, leaf water potential, recovery,BVOC}, number = {7}, pages = {1186--1197}, title = {{Central European 2018 hot drought shifts scots pine forest to its tipping point}}, url = {https://onlinelibrary.wiley.com/doi/abs/10.1111/plb.13455}, volume = {24}, year = {2022} } @article{wes-7-1183-2022, author = {Hallgren, C and Arnqvist, J and Nilsson, E and Ivanell, S and Shapkalijevski, M and Thomasson, A and Pettersson, H and Sahl{\'{e}}e, E}, doi = {10.5194/wes-7-1183-2022}, journal = {Wind Energy Science}, number = {3}, pages = {1183--1207}, title = {{Classification and properties of non-idealized coastal wind profiles -- an observational study}}, url = {https://wes.copernicus.org/articles/7/1183/2022/}, volume = {7}, year = {2022} } @article{Harris2022, abstract = {Anthropogenic nitrogen inputs cause major negative environmental impacts, including emissions of the important greenhouse gas N2O. Despite their importance, shifts in terrestrial N loss pathways driven by global change are highly uncertain. Here we present a coupled soil-atmosphere isotope model (IsoTONE) to quantify terrestrial N losses and N2O emission factors from 1850-2020. We find that N inputs from atmospheric deposition caused 51% of anthropogenic N2O emissions from soils in 2020. The mean effective global emission factor for N2O was 4.3 ± 0.3% in 2020 (weighted by N inputs), much higher than the surface area-weighted mean (1.1 ± 0.1%). Climate change and spatial redistribution of fertilisation N inputs have driven an increase in global emission factor over the past century, which accounts for 18% of the anthropogenic soil flux in 2020. Predicted increases in fertilisation in emerging economies will accelerate N2O-driven climate warming in coming decades, unless targeted mitigation measures are introduced.}, author = {Harris, E and Yu, L and Wang, Y-P. and Mohn, J and Henne, S and Bai, E and Barthel, M and Bauters, M and Boeckx, P and Dorich, C and Farrell, M and Krummel, P B and Loh, Z M and Reichstein, M and Six, J and Steinbacher, M and Wells, N S and Bahn, M and Rayner, P}, doi = {10.1038/s41467-022-32001-z}, issn = {2041-1723}, journal = {Nature Communications}, number = {1}, pages = {4310}, title = {{Warming and redistribution of nitrogen inputs drive an increase in terrestrial nitrous oxide emission factor}}, url = {https://doi.org/10.1038/s41467-022-32001-z}, volume = {13}, year = {2022} } @article{HARTMAN2021102508, abstract = {Until the 1980s, the deep sea was generally considered to be a particularly stable environment, free from major temporal variations (Sanders, 1968). Studies in the abyssal northeast Atlantic by Billett et al. (1983), and subsequently Lampitt (1985) discovered seasonal pulses of surface primary production-derived particulate organic matter (phytodetritus), and hence carbon, at abyssal depths. These early observations were subsequently extended to the central oceanic region of the NE Atlantic (Pfannkuche, 1993; Thiel et al., 1989), and prompted the establishment of more concerted time series studies in the Porcupine Abyssal Plain area. Today, the Porcupine Abyssal Plain Sustained Observatory (PAP–SO) is a multidisciplinary open-ocean time series site in the NE Atlantic (48°50′N 16°30′W, 4850 m water depth; Fig. 1), focused on the study of connections between the surface and deep ocean. In situ measurements of climatically and environmentally relevant variables have been made for more than 30 years. This represents an exceptionally long time series - a recent compilation of biological time series data, across terrestrial, freshwater, and marine realms, indicates an average duration of only 13-years (Dornelas et al., 2018). Long-term time series in the deep sea are rare, particularly those collecting data from surface to seabed. The PAP-SO is one of two abyssal long-term time series sites globally (Smith et al. 2015), the other being a thirty-year time series at Station M in the northeastern Pacific Ocean (34°50′N, 123°00′W, $\sim$4000 m water depth), maintained by the Monterey Bay Aquarium Research Institute (Smith et al., 2020). This ‘sibling' abyssal time series site also aims to understand the connections between the surface ocean and the seabed, using many similar techniques (Smith et al., 2017), facilitating comparisons between the two sites (e.g. Durden et al., 2019; Durden et al., 2020a; Laguionie-Marchais et al., 2013; Smith et al., 2009). Another source of extended comparison is the 21 year time series Long-Term Ecological Research Observatory HAUSGARTEN, Frontiers in Arctic Marine Monitoring (FRAM) in the Fram Strait between the North Atlantic and the central Arctic Ocean (78.5°N–80°N, 05°W–11°E, 250–5500 m water depth), maintained by the Alfred Wegener Institute for Polar and Marine Research (Soltwedel et al., 2016; Soltwedel et al., 2005). Much of our understanding of temporal variation in the deep sea, and connections between the surface ocean and the seabed have been derived from research conducted at these observatories.}, author = {Hartman, Susan E and Bett, Brian J and Durden, Jennifer M and Henson, Stephanie A and Iversen, Morten and Jeffreys, Rachel M and Horton, Tammy and Lampitt, Richard and Gates, Andrew R}, doi = {https://doi.org/10.1016/j.pocean.2020.102508}, issn = {0079-6611}, journal = {Progress in Oceanography}, keywords = { Essential climate variables, Northeast Atlantic, PAP-SO, Time series,Porcupine Abyssal Plain Sustained Observatory}, pages = {102508}, title = {{Enduring science: Three decades of observing the Northeast Atlantic from the Porcupine Abyssal Plain Sustained Observatory (PAP-SO)}}, url = {https://www.sciencedirect.com/science/article/pii/S0079661120302433}, volume = {191}, year = {2021} } @article{bg-19-2121-2022, author = {Havu, M and Kulmala, L and Kolari, P and Vesala, T and Riikonen, A and J{\"{a}}rvi, L}, doi = {10.5194/bg-19-2121-2022}, journal = {Biogeosciences}, number = {8}, pages = {2121--2143}, title = {{Carbon sequestration potential of street tree plantings in Helsinki}}, url = {https://bg.copernicus.org/articles/19/2121/2022/}, volume = {19}, year = {2022} } @article{essd-14-2501-2022, author = {Heistermann, M and Bogena, H and Francke, T and G{\"{u}}ntner, A and Jakobi, J and Rasche, D and Schr{\"{o}}n, M and D{\"{o}}pper, V and Fersch, B and Groh, J and Patil, A and P{\"{u}}tz, T and Reich, M and Zacharias, S and Zengerle, C and Oswald, S}, doi = {10.5194/essd-14-2501-2022}, journal = {Earth System Science Data}, number = {5}, pages = {2501--2519}, title = {{Soil moisture observation in a forested headwater catchment: combining a dense cosmic-ray neutron sensor network with roving and hydrogravimetry at the TERENO site W{\"{u}}stebach}}, url = {https://essd.copernicus.org/articles/14/2501/2022/}, volume = {14}, year = {2022} } @article{Helbig2022, abstract = {Peatlands have acted as net CO2 sinks over millennia, exerting a global climate cooling effect. Rapid warming at northern latitudes, where peatlands are abundant, can disturb their CO2 sink function. Here we show that sensitivity of peatland net CO2 exchange to warming changes in sign and magnitude across seasons, resulting in complex net CO2 sink responses. We use multiannual net CO2 exchange observations from 20 northern peatlands to show that warmer early summers are linked to increased net CO2 uptake, while warmer late summers lead to decreased net CO2 uptake. Thus, net CO2 sinks of peatlands in regions experiencing early summer warming, such as central Siberia, are more likely to persist under warmer climate conditions than are those in other regions. Our results will be useful to improve the design of future warming experiments and to better interpret large-scale trends in peatland net CO2 uptake over the coming few decades.}, author = {Helbig, M and {\v{Z}}ivkovi{\'{c}}, T and Alekseychik, P and Aurela, M and El-Madany, T S and Euskirchen, E S and Flanagan, L B and Griffis, T J and Hanson, P J and Hattakka, J and Helfter, C and Hirano, T and Humphreys, E R and Kiely, G and Kolka, R K and Laurila, T and Leahy, P G and Lohila, A and Mammarella, I and Nilsson, M B and Panov, A and Parmentier, F J W and Peichl, M and Rinne, J and Roman, D T and Sonnentag, O and Tuittila, E.-S and Ueyama, M and Vesala, T and Vestin, P and Weldon, S and Weslien, P and Zaehle, S}, doi = {10.1038/s41558-022-01428-z}, issn = {1758-6798}, journal = {Nature Climate Change}, number = {8}, pages = {743--749}, title = {{Warming response of peatland CO2 sink is sensitive to seasonality in warming trends}}, url = {https://doi.org/10.1038/s41558-022-01428-z}, volume = {12}, year = {2022} } @article{HOLLOS2022105556, abstract = {Application of process-based models at different spatial scales requires their proper parameterization. This task is typically executed using trial-and-error parameter adjustment or a probabilistic method. Practical application of the probabilistic methods is hampered by methodological complexity and lack of interpretability. Here we present a novel approach for the parameterization of process-based models that we call as conditional interval refinement method (CIRM). The method can be best described as the combination of a probabilistic approach and the advantages of the expert-based parameter adjustment. CIRM was demonstrated by optimizing the Biome-BGCMuSo biogeochemical model using maize yield observations. The proposed approach uses the General Likelihood Uncertainty Estimation (GLUE) method with additional expert knowledge, supplemented by the construction and interpretation of decision trees. It was demonstrated that the iterative, fully automatic method successfully constrained the parameter intervals meanwhile our confidence on the parameters increased. The algorithm can easily be implemented with other process-based models.}, author = {Holl{\'{o}}s, R and Fodor, N and Mergani{\v{c}}ov{\'{a}}, K and Hidy, D and {\'{A}}rend{\'{a}}s, T and Gr{\"{u}}nwald, T and Barcza, Z}, doi = {https://doi.org/10.1016/j.envsoft.2022.105556}, issn = {1364-8152}, journal = {Environmental Modelling & Software}, keywords = { Bayesian calibration, Decision tree, Parameter constraints,Model optimization}, pages = {105556}, title = {{Conditional interval reduction method: A possible new direction for the optimization of process based models}}, url = {https://www.sciencedirect.com/science/article/pii/S1364815222002560}, volume = {158}, year = {2022} } @article{Hough2022, abstract = {Abstract Permafrost thaw is a major potential feedback source to climate change as it can drive the increased release of greenhouse gases carbon dioxide (CO2) and methane (CH4). This carbon release from the decomposition of thawing soil organic material can be mitigated by increased net primary productivity (NPP) caused by warming, increasing atmospheric CO2, and plant community transition. However, the net effect on C storage also depends on how these plant community changes alter plant litter quantity, quality, and decomposition rates. Predicting decomposition rates based on litter quality remains challenging, but a promising new way forward is to incorporate measures of the energetic favorability to soil microbes of plant biomass decomposition. We asked how the variation in one such measure, the nominal oxidation state of carbon (NOSC), interacts with changing quantities of plant material inputs to influence the net C balance of a thawing permafrost peatland. We found: (1) Plant productivity (NPP) increased post-thaw, but instead of contributing to increased standing biomass, it increased plant biomass turnover via increased litter inputs to soil; (2) Plant litter thermodynamic favorability (NOSC) and decomposition rate both increased post-thaw, despite limited changes in bulk C:N ratios; (3) these increases caused the higher NPP to cycle more rapidly through both plants and soil, contributing to higher CO2 and CH4 fluxes from decomposition. Thus, the increased C-storage expected from higher productivity was limited and the high global warming potential of CH4 contributed a net positive warming effect. Although post-thaw peatlands are currently C sinks due to high NPP offsetting high CO2 release, this status is very sensitive to the plant community's litter input rate and quality. Integration of novel bioavailability metrics based on litter chemistry, including NOSC, into studies of ecosystem dynamics, is needed to improve the understanding of controls on arctic C stocks under continued ecosystem transition.}, annote = {https://doi.org/10.1111/gcb.15970}, author = {Hough, Moira and McCabe, Samantha and Vining, S Rose and {Pickering Pedersen}, Emily and Wilson, Rachel M and Lawrence, Ryan and Chang, Kuang-Yu and Bohrer, Gil and Coordinators, The IsoGenie and Riley, William J and Crill, Patrick M and Varner, Ruth K and Blazewicz, Steven J and Dorrepaal, Ellen and Tfaily, Malak M and Saleska, Scott R and Rich, Virginia I}, doi = {https://doi.org/10.1111/gcb.15970}, issn = {1354-1013}, journal = {Global Change Biology}, keywords = {C storage,NOSC,Stordalen Mire,decomposition,litter chemistry,peat,permafrost thaw,plant community change}, month = {feb}, number = {3}, pages = {950--968}, publisher = {John Wiley & Sons, Ltd}, title = {{Coupling plant litter quantity to a novel metric for litter quality explains C storage changes in a thawing permafrost peatland}}, url = {https://doi.org/10.1111/gcb.15970}, volume = {28}, year = {2022} } @article{HU2022113120, abstract = {Ecosystem primary productivity is a key ecological process influencing many ecosystem services, including carbon storage. Thus, clarifying how primary productivity in terrestrial ecosystems responds to climatic variability can reveal key mechanisms that will drive future changes in the global carbon budget. Satellite products of canopy greenness are widely used as proxies for vegetation productivity to evaluate how ecosystems respond to climate variability. However, to what degree inter-annual variations in productivity are consistent with greenness and how this relationship varies spatially remains unclear. Here we investigated the strength of the coupling between inter-annual variations in leaf area index (LAI, a measure of greenness) and ecosystem gross primary productivity (GPP) derived from eddy covariance towers, i.e., the r2 of the LAI-GPP relationship. Overall, inter-annual GPP and LAI were highly coupled (i.e., high r2) in arid grasslands, but were fully decoupled in mesic evergreen broadleaf forests, indicating that this relationship varies strongly along aridity gradients. A possible mechanism of the spatial variation in the LAI-GPP relationship is that the tradeoff between ecosystem structure (LAI) and physiology (photosynthesis per unit leaf area) becomes stronger in more humid climates. Land models overestimated the r2 of LAI-GPP correlation for most ecosystem types and failed to capture the spatial pattern along aridity gradients. We conclude that relying on greenness products for evaluating inter-annual changes in vegetation productivity may bias assessments, especially in tropical rainforest ecosystems. Our findings may also reconcile observed disparities between responses in greenness and GPP during drought in Amazon forests.}, author = {Hu, Zhongmin and Piao, Shilong and Knapp, Alan K and Wang, Xuhui and Peng, Shushi and Yuan, Wenping and Running, Steve and Mao, Jiafu and Shi, Xiaoying and Ciais, Philippe and Huntzinger, Deborah N and Yang, Jia and Yu, Guirui}, doi = {https://doi.org/10.1016/j.rse.2022.113120}, issn = {0034-4257}, journal = {Remote Sensing of Environment}, keywords = { Greenness, Inter-annual variability, Land models, Leaf area index, Light-use efficiency,Gross primary productivity}, pages = {113120}, title = {{Decoupling of greenness and gross primary productivity as aridity decreases}}, url = {https://www.sciencedirect.com/science/article/pii/S0034425722002346}, volume = {279}, year = {2022} } @article{rs14051133, abstract = {The study of anthropogenic carbon monoxide (CO) emissions is crucial to investigate anthropogenic activities. Assuming the anthropogenic CO emissions accounted for the super majority of the winter CO fluxes in western Europe, they could be roughly estimated by the inversion approach. The CO fluxes and concentrations of four consecutive winter seasons (i.e., December–February) in western Europe since 2017 were estimated by a regional CO flux inversion system based on the Weather Research and Forecasting model coupled with Chemistry (WRF-Chem) and the Data Assimilation Research Testbed (DART). The CO retrievals from the Measurements Of Pollution In The Troposphere instrument (MOPITT) version 8 level 2 multi-spectral Thermal InfraRed (TIR)/Near-InfraRed (NIR) CO retrieval data products were assimilated by the inversion system. The analyses of the MOPITT data used by the inversion system indicated that the mean averaging kernel row sums of the surface level was about 0.25, and the difference percentage of the surface-level retrievals relative to a priori CO-mixing ratios was 14.79%, which was similar to that of the other levels. These results suggested the MOPITT’s surface-level observations contained roughly the same amount of information as the other levels. The inverted CO fluxes of the four winter seasons were 6198.15 kilotons, 4939.72 kilotons, 4697.80 kilotons, and 5456.19 kilotons, respectively. Based on the assumption, the United Nations Framework Convention on Climate Change (UNFCCC) inventories were used to evaluate the accuracy of the inverted CO fluxes. The evaluation results indicated that the differences between the inverted CO fluxes and UNFCCC inventories of the three winter seasons of 2017–2019 were 13.36%, −4.59%, and −4.76%, respectively. Detailed surface-CO concentrations and XCO comparative analyses between the experimental results and the external Community Atmosphere Model with Chemistry (CAM-Chem) results and the MOPITT data were conducted. The comparative analysis results indicated that the experimental results of the winter season of 2017 were obviously affected by high boundary conditions. The CO concentrations results of the experiments were also evaluated by the CO observation data from Integrated Carbon Observation System (ICOS), the average Mean Bias Error (MBE), and the Root Mean Square Error (RMSE) between the CO concentrations results of the inversion system, and the ICOS observations were −22.43 ppb and 57.59 ppb, respectively. The MBE and RMSE of the inversion system were 17.53-ppb and 4.17-ppb better than those of the simulation-only parallel experiments, respectively.}, author = {Huang, Yongjian and Wei, Jianming and Jin, Jiupin and Zhou, Zhiwei and Gu, Qianrong}, doi = {10.3390/rs14051133}, issn = {2072-4292}, journal = {Remote Sensing}, number = {5}, title = {{CO Fluxes in Western Europe during 2017–2020 Winter Seasons Inverted by WRF-Chem/Data Assimilation Research Testbed with MOPITT Observations}}, url = {https://www.mdpi.com/2072-4292/14/5/1133}, volume = {14}, year = {2022} } @article{bg-2022-125, author = {Jaakkola, E and G{\"{a}}rtner, A and J{\"{o}}nsson, A M and Ljung, K and Olsson, P.-O. and Holst, T}, doi = {10.5194/bg-2022-125}, journal = {Biogeosciences Discussions}, pages = {1--32}, title = {{Spruce bark beetle (\textit{Ips typographus}) infestation cause up to 700 times higher bark BVOC emission rates from Norway spruce (\textit{Picea abies})}}, url = {https://bg.copernicus.org/preprints/bg-2022-125/}, volume = {2022}, year = {2022} } @article{https://doi.org/10.1029/2022WR031972, abstract = {Abstract Cosmic-ray neutron sensors (CRNS) enable noninvasive determination of field-scale soil moisture content by exploiting the dependence of the intensity of aboveground epithermal neutrons on the hydrogen contained in soil moisture. However, there are other hydrogen pools besides soil moisture (e.g., biomass). Therefore, these hydrogen pools should be considered for accurate soil moisture content measurements, especially when they are changing dynamically (e.g., arable crops, deforestation, and reforestation). In this study, we test four approaches for the correction of biomass effects on soil moisture content measurements with CRNS using experiments with three crops (sugar beet, winter wheat, and maize) based on high-quality reference soil moisture: (a) site-specific functions based on in-situ measured biomass, (b) a generic approach, (c) the thermal-to-epithermal neutron ratio (Nr), and (d) the thermal neutron intensity. Bare soil calibration of the CRNS resulted in high root mean square errors (RMSEs) of 0.097, 0.041, and 0.019 m³/m³ between estimated and reference soil moisture content for sugar beet, winter wheat, and maize, respectively. Considering in-situ measured biomass for correction reduced the RMSE to 0.015, 0.018, and 0.009 m³/m³. The consideration of thermal neutron intensity for correction was similarly accurate. We also explored the use of CRNS for biomass estimation and found that Nr only provided accurate biomass estimates for sugar beet. In contrast, we found significant site-specific relationships between biomass and thermal neutron intensity for all three crops, suggesting that thermal neutron intensity can be used both to improve CRNS-based soil moisture content measurements and to quantify crop biomass.}, annote = {e2022WR031972 2022WR031972}, author = {Jakobi, J and Huisman, J A and Fuchs, H and Vereecken, H and Bogena, H R}, doi = {https://doi.org/10.1029/2022WR031972}, journal = {Water Resources Research}, keywords = { biomass estimation, biomass influence, cosmic ray neutron sensing, thermal neutrons,soil moisture}, number = {8}, pages = {e2022WR031972}, title = {{Potential of Thermal Neutrons to Correct Cosmic-Ray Neutron Soil Moisture Content Measurements for Dynamic Biomass Effects}}, url = {https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2022WR031972}, volume = {58}, year = {2022} } @article{acp-22-6717-2022, author = {Jakobsson, J K F and Waman, D B and Phillips, V T J and {Bjerring Kristensen}, T}, doi = {10.5194/acp-22-6717-2022}, journal = {Atmospheric Chemistry and Physics}, number = {10}, pages = {6717--6748}, title = {{Time dependence of heterogeneous ice nucleation by ambient aerosols: laboratory observations and a formulation for models}}, url = {https://acp.copernicus.org/articles/22/6717/2022/}, volume = {22}, year = {2022} } @article{JIA2022100210, abstract = {Sudden mega natural gas leaks of two Nord Stream pipelines in the Baltic Sea (Denmark) occurred from late September to early October 2022, releasing large amounts of methane into the atmosphere. We inferred the methane emissions of this event based on surface in situ observations using two inversion methods and two meteorological reanalysis datasets, supplemented with satellite-based observations. We conclude that approximately 220 ± 30 Gg of methane was released from September 26 to October 1, 2022.}, author = {Jia, Mengwei and Li, Fei and Zhang, Yuzhong and Wu, Mousong and Li, Yingsong and Feng, Shuzhuang and Wang, Hengmao and Chen, Huilin and Ju, Weimin and Lin, Jun and Cai, Jianwei and Zhang, Yongguang and Jiang, Fei}, doi = {https://doi.org/10.1016/j.ese.2022.100210}, issn = {2666-4984}, journal = {Environmental Science and Ecotechnology}, pages = {100210}, title = {{The Nord Stream pipeline gas leaks released approximately 220,000 tonnes of methane into the atmosphere}}, url = {https://www.sciencedirect.com/science/article/pii/S2666498422000667}, volume = {12}, year = {2022} } @article{https://doi.org/10.1111/geb.13581, abstract = {Abstract Aim Initiation of autumnal leaf senescence is crucial for plant overwintering and ecosystem dynamics. Previous studies have focused on the advanced stages of autumnal leaf senescence and reported that climatic warming delayed senescence, despite the fundamental differences among the stages of senescence. However, the timing of onset of leaf coloration (DLCO), the earliest visual sign of senescence, has rarely been studied. Here, we assessed the response of DLCO to temperature. Location 30–75° N in the Northern Hemisphere. Time period 2000–2018. Major taxa studied Deciduous vegetation. Methods We retrieved DLCO from high-temporal-resolution satellite data, which were then validated by PhenoCam observations. We investigated the temporal changes in DLCO and the relationship between DLCO and temperature by using satellite and ground observations. Results DLCO was not significantly (p > .05) delayed between 2000 and 2018 in 94\% of the area. DLCO was positively (p < .05) correlated with pre-DLCO mean daily minimum temperature (Tmin) in only 9\% of the area, whereas the end of leaf coloration (DLCE) was positively correlated with pre-DLCE mean Tmin over a larger area (34\%). Further analyses showed that warming slowed the progress of leaf coloration. Interestingly, DLCO was less responsive to pre-DLCO mean Tmin in areas where daylength was longer across the Northern Hemisphere, particularly for woody vegetation. Main conclusions The rate of progress of coloration is more sensitive to temperature than its start date, resulting in an extension of the duration of leaf senescence under warming. The dependence of DLCO response to temperature on daylength indicates stronger photoperiodic control on initiation of leaf senescence in areas with longer daylength (i.e., shorter nights), possibly because plants respond to the length of uninterrupted darkness rather than daylength. This study indicates that the onset of leaf coloration was not responsive to climate warming and provides observational evidence of photoperiod control of autumnal leaf senescence at biome and continental scales.}, author = {Jiang, Nan and Shen, Miaogen and Ciais, Philippe and Campioli, Matteo and Pe{\~{n}}uelas, Josep and K{\"{o}}rner, Christian and Cao, Ruyin and Piao, Shilong and Liu, Licong and Wang, Shiping and Liang, Eryuan and Delpierre, Nicolas and Soudani, Kamel and Rao, Yuhan and Montagnani, Leonardo and H{\"{o}}rtnagl, Lukas and Paul-Limoges, Eug{\'{e}}nie and Myneni, Ranga and Wohlfahrt, Georg and Fu, Yongshuo and {\v{S}}igut, Ladislav and Varlagin, Andrej and Chen, Jin and Tang, Yanhong and Zhao, Wenwu}, doi = {https://doi.org/10.1111/geb.13581}, journal = {Global Ecology and Biogeography}, keywords = { Northern Hemisphere, global warming, leaf coloration onset, photoperiod,autumnal leaf senescence}, number = {11}, pages = {2297--2313}, title = {{Warming does not delay the start of autumnal leaf coloration but slows its progress rate}}, url = {https://onlinelibrary.wiley.com/doi/abs/10.1111/geb.13581}, volume = {31}, year = {2022} } @article{https://doi.org/10.1029/2021GL096069, abstract = {Abstract Water storage plays an important role in mitigating heat and flooding in urban areas. Assessment of the water storage capacity of cities remains challenging due to the inherent heterogeneity of the urban surface. Traditionally, effective storage has been estimated from runoff. Here, we present a novel approach to estimate effective water storage capacity from recession rates of observed evaporation during precipitation-free periods. We test this approach for cities at neighborhood scale with eddy-covariance based latent heat flux observations from 14 contrasting sites with different local climate zones, vegetation cover and characteristics, and climates. Based on analysis of 583 drydowns, we find storage capacities to vary between 1.3 and 28.4 mm, corresponding to e-folding timescales of 1.8–20.1 days. This makes the urban storage capacity at least five times smaller than all the observed values for natural ecosystems, reflecting an evaporation regime characterized by extreme water limitation.}, annote = {e2021GL096069 2021GL096069}, author = {Jongen, H J and Steeneveld, G J and Beringer, J and Christen, A and Chrysoulakis, N and Fortuniak, K and Hong, J and Hong, J W and Jacobs, C M J and J{\"{a}}rvi, L and Meier, F and Pawlak, W and Roth, M and Theeuwes, N E and Velasco, E and Vogt, R and Teuling, A J}, doi = {https://doi.org/10.1029/2021GL096069}, journal = {Geophysical Research Letters}, keywords = { recession analysis,urban climate}, number = {3}, pages = {e2021GL096069}, title = {{Urban Water Storage Capacity Inferred From Observed Evapotranspiration Recession}}, url = {https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2021GL096069}, volume = {49}, year = {2022} } @article{bg-19-3151-2022, author = {Juutinen, S and Aurela, M and Tuovinen, J.-P. and Ivakhov, V and Linkosalmi, M and R{\"{a}}s{\"{a}}nen, A and Virtanen, T and Mikola, J and Nyman, J and V{\"{a}}h{\"{a}}, E and Loskutova, M and Makshtas, A and Laurila, T}, doi = {10.5194/bg-19-3151-2022}, journal = {Biogeosciences}, number = {13}, pages = {3151--3167}, title = {{Variation in CO$_{2}$ and CH$_{4}$ fluxes among land cover types in heterogeneous Arctic tundra in northeastern Siberia}}, url = {https://bg.copernicus.org/articles/19/3151/2022/}, volume = {19}, year = {2022} } @article{bg-19-4067-2022, author = {Kohonen, K.-M. and Dewar, R and Tramontana, G and Mauranen, A and Kolari, P and Kooijmans, L M J and Papale, D and Vesala, T and Mammarella, I}, doi = {10.5194/bg-19-4067-2022}, journal = {Biogeosciences}, number = {17}, pages = {4067--4088}, title = {{Intercomparison of methods to estimate gross primary production based on \chem{CO_2} and COS flux measurements}}, url = {https://bg.copernicus.org/articles/19/4067/2022/}, volume = {19}, year = {2022} } @article{bg-19-2025-2022, author = {Korkiakoski, M and M{\"{a}}{\"{a}}tt{\"{a}}, T and Peltoniemi, K and Penttil{\"{a}}, T and Lohila, A}, doi = {10.5194/bg-19-2025-2022}, journal = {Biogeosciences}, number = {7}, pages = {2025--2041}, title = {{Excess soil moisture and fresh carbon input are prerequisites for methane production in podzolic soil}}, url = {https://bg.copernicus.org/articles/19/2025/2022/}, volume = {19}, year = {2022} } @article{https://doi.org/10.1029/2021JG006774, abstract = {Abstract Peatlands, with high spatial variability in ecotypes and microforms, constitute a significant part of the boreal landscape and play an important role in the global carbon (C) cycle. However, the effects of this peatland heterogeneity within the boreal landscape are rarely quantified. Here, we use field-based measurements, high-resolution land cover classification, and biogeochemical and atmospheric models to estimate the atmosphere-ecosystem C fluxes and the corresponding radiative effect (RE) for a boreal landscape (Kaamanen) in northern Finland. Our result shows that the Kaamanen catchment currently functioned as a sink of carbon dioxide (CO2) and a source of methane (CH4). Peatlands (26\% of the area) contributed 22\% of the total CO2 uptake and 89\% of CH4 emissions; forests (61\%) accounted for 78\% of CO2 uptake and offset 6\% of CH4 emissions; water bodies (13\%) offset 7\% of CO2 uptake and contributed 11\% of CH4 emissions. The heterogeneity of peatlands accounted for 11\%, 88\%, and 75\% of the area-weighted variability (deviation from the area-weighted mean among different land cover types (LCTs) within the catchment) in CO2 flux, CH4 flux, and the combined RE of CO2 and CH4 exchanges over the 25-year time horizon, respectively. Aggregating peatland LCTs or misclassifying them as nonpeatland LCTs can significantly (p < 0.05) bias the regional CH4 exchange and RE estimates, while differentiating between drier noninundated and wetter inundated peatlands can effectively reduce the bias. Current land cover products lack such details in peatland heterogeneity, which would be needed to better constrain boreal C budgets and global C-climate feedbacks.}, annote = {e2021JG006774 2021JG006774}, author = {Kou, Dan and Virtanen, Tarmo and Treat, Claire C and Tuovinen, Juha-Pekka and R{\"{a}}s{\"{a}}nen, Aleksi and Juutinen, Sari and Mikola, Juha and Aurela, Mika and Heiskanen, Lauri and Heikkil{\"{a}}, Maija and Weckstr{\"{o}}m, Jan and Juselius, Teemu and Piilo, Sanna R and Deng, Jia and Zhang, Yu and Chaudhary, Nitin and Huang, Conghong and V{\"{a}}liranta, Minna and Biasi, Christina and Liu, Xiangyu and Guo, Mingyang and Zhuang, Qianlai and Korhola, Atte and Shurpali, Narasinha J}, doi = {https://doi.org/10.1029/2021JG006774}, journal = {Journal of Geophysical Research: Biogeosciences}, keywords = { carbon, heterogeneity, landscape, peatland, radiative effect,boreal}, number = {9}, pages = {e2021JG006774}, title = {{Peatland Heterogeneity Impacts on Regional Carbon Flux and Its Radiative Effect Within a Boreal Landscape}}, url = {https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2021JG006774}, volume = {127}, year = {2022} } @article{KOVAC2022154681, abstract = {We used automated spectroradiometers to continuously monitor changes in the optical parameters of phenological and photosynthetic traits in beech and spruce forests. We examined seasonal variations in the normalized difference vegetation index (NDVI), photochemical reflectance index (PRI), and solar-induced fluorescence in the oxygen A band (SIFA) that was estimated using a 3-FLD discrimination method from radiance data. The optical parameters tracked the activation and cessation of photosynthesis in spring and autumn. Data at photon fluxes >1200 $\mu$mol m−2 s−1 during extended noon hours were used to link the seasonal PRI and SIFA variations to the dynamics of photosynthesis. Seasonal PRI was significantly correlated with photosynthetic light-use efficiency (LUE) with R2 values of 0.66 and 0.48 for the measurements in beech and spruce forests, respectively. SIFA emissions were significantly correlated with the gross primary production (GPP) of the evergreen spruce forest (R2 = 0.47), but R2 was only 0.13 when measured in the beech forest. The correlations between the optical parameters and GPP or LUE, however, tended to be lower when using a dataset with constant NDVI. Introducing an equation combining NDVI, PRI, and the quantum yield of SIFA emission increased R2 for LUE estimation to 0.77 in the spruce forest and 0.63 in the beech forest. GPP was estimated from the parametric equation with improved accuracy reaching R2 = 0.53 and RMSE = 5.95 $\mu$mol CO2 m−2 s−1 in spruce forest and R2 = 0.58 and RMSE = 5.23 $\mu$mol CO2 m−2 s−1 in beech forest. Parametric equations were more efficient in estimating photosynthesis in datasets that consisted of an entire season's data. By combining NDVI, PRI and the quantum yield of SIFA, we could thus substantially improve estimations of carbon fluxes in diverse deciduous and evergreen canopies.}, author = {Kov{\'{a}}{\v{c}}, Daniel and A{\v{c}}, Alexander and {\v{S}}igut, Ladislav and Pe{\~{n}}uelas, Josep and Grace, John and Urban, Otmar}, doi = {https://doi.org/10.1016/j.scitotenv.2022.154681}, issn = {0048-9697}, journal = {Science of The Total Environment}, keywords = { Chlorophyll fluorescence, Eddy covariance fluxes, NDVI, Photochemical reflectance index, Seasonal dynamics,3-FLD}, pages = {154681}, title = {{Combining NDVI, PRI and the quantum yield of solar-induced fluorescence improves estimations of carbon fluxes in deciduous and evergreen forests}}, url = {https://www.sciencedirect.com/science/article/pii/S0048969722017740}, volume = {829}, year = {2022} } @article{KRASNOVA2022109042, abstract = {In summer 2018, Europe experienced a heatwave that impacted the forest carbon cycle. We assessed the influence of elevated temperatures on the carbon exchange of three forest stands of different types (coniferous, deciduous, and conifer-broadleaved) and a clear-cut area located in the geographical vicinity within a hemiboreal zone. The carbon fluxes were calculated using the eddy-covariance technique. Over the period of anomaly high temperatures, the NEE of a deciduous (alder) forest was similar to the previous year due to the reduction of both GPP and ER of the same magnitude. Warm days in spring and autumn allowed for the GPP offset, and the total NEE of vegetation season 2018 was more negative than of 2017. Coniferous (pine and spruce) forest carbon uptake decreased during the temperature anomaly as a result of GPP reduction being higher than the decrease in ER. Spring warming had almost no effect on the carbon exchange, while ER and GPP increased in autumn warm days. As a result, annual ER was higher in 2018 than in 2017, and the NEE was smaller. The coniferous forest was most resistant to the heatwave, most probably because of its adaption to low soil water content. Contrary to our expectations, a mixed conifer-broadleaved forest (pine, spruce, birch, clear-cuts) was more affected by the heatwave than a pine-dominated forest. It switched from net carbon sink during the vegetation season of 2017 to net carbon source in 2018. Almost three times higher amount of carbon was released in 2018 as a result of GPP reduction. The clear-cut area carbon exchange was the most vulnerable to the heatwave influence out of all study sites. A more prominent reduction of GPP resulted in smaller NEE. Warm days in spring and autumn did not offset the temperature anomaly impact, as was observed for the forested ecosystems.}, author = {Krasnova, A and Mander, {\"{U}} and Noe, S M and Uri, V and Krasnov, D and Soosaar, K}, doi = {https://doi.org/10.1016/j.agrformet.2022.109042}, issn = {0168-1923}, journal = {Agricultural and Forest Meteorology}, keywords = { Clear-cut, Drought, Eddy-covariance, Mixed forest, Net ecosystem exchange,Carbon exchange}, pages = {109042}, title = {{Hemiboreal forests' CO2 fluxes response to the European 2018 heatwave}}, url = {https://www.sciencedirect.com/science/article/pii/S0168192322002313}, volume = {323}, year = {2022} } @article{KREJZA2022104787, abstract = {Although forests store significant amounts of carbon in tree stems, the extent to which stem growth depends on carbon assimilation and environmental factors is poorly understood. In this study, gross primary productivity (GPP) and net ecosystem productivity (NEP) are compared for the first time at daily resolution with stem carbon allocation (SCA) in a spruce forest. We found substantial differences in the seasonal patterns of all variables as a function of environmental conditions, leading to three important findings. First, carbon uptake was only marginally invested in wood growth during the first half of the growing season. This means that there were other priorities for carbon allocation than stem growth at this time of year. Second, our results show that SRI at the beginning of the stem growth period, which mainly involves cell division and expansion, is a process that requires less carbon than the process of xylem lignification and thickening that follows. And third, NEP was generally less sensitive to drought than SCA. This suggests that the carbon uptake balance is less sensitive to dry periods than growth, particularly because the carbon uptake period is much longer than the growth window. These results may change the way we perceive the effects of climate change on forests, as tree carbon dynamics are primarily explained by the seasonal timing of dry periods rather than the intensity of these events.}, author = {Krejza, Jan and Haeni, Matthias and Darenova, Eva and Folt{\'{y}}nov{\'{a}}, Lenka and Fajstavr, Marek and {Jan Sv{\v{e}}tl{\'{i}}k} and Nezval, Ondřej and Bedn{\'{a}}ř, Pavel and {\v{S}}igut, Ladislav and Hor{\'{a}}{\v{c}}ek, Petr and Zweifel, Roman}, doi = {https://doi.org/10.1016/j.envexpbot.2022.104787}, issn = {0098-8472}, journal = {Environmental and Experimental Botany}, keywords = { , Carbon flux, Dendrometer, Drought stress, Eddy covariance, Forest inventory, Partitioning, Stem radial increment, Tree ring, Wood formation, Xylogenesis,Carbon balance}, pages = {104787}, title = {{Disentangling carbon uptake and allocation in the stems of a spruce forest}}, url = {https://www.sciencedirect.com/science/article/pii/S0098847222000090}, volume = {196}, year = {2022} } @article{esd-13-633-2022, author = {Kuli{\'{n}}ski, K and Rehder, G and Asmala, E and Bartosova, A and Carstensen, J and Gustafsson, B and Hall, P O J and Humborg, C and Jilbert, T and J{\"{u}}rgens, K and Meier, H E M and M{\"{u}}ller-Karulis, B and Naumann, M and Olesen, J E and Savchuk, O and Schramm, A and Slomp, C P and Sofiev, M and Sobek, A and Szymczycha, B and Undeman, E}, doi = {10.5194/esd-13-633-2022}, journal = {Earth System Dynamics}, number = {1}, pages = {633--685}, title = {{Biogeochemical functioning of the Baltic Sea}}, url = {https://esd.copernicus.org/articles/13/633/2022/}, volume = {13}, year = {2022} } @article{LELANDAIS2022119020, abstract = {Since 2014, a 100 m tall tower measures continuously greenhouse gases at the Observatoire de haute Provence (OHP) located in the southeast of France (43° 55′ 51″ N, 5° 42′ 48″ E) as a monitoring station of the French National Greenhouse Gases Observation network (ICOS-Fr). This rural station allows to study the short, mid, and long terms variability of atmospheric CO2, CH4 and CO concentrations at the continental, regional and local scales in a region characterized by a Mediterranean climate. Measurements are performed using cavity ring-down spectroscopy at three levels above ground level (AGL); 10 m, 50 m and 100 m. Using the ICOS European Infrastructure procedure to calibrate and ensure the data quality control, the precision of our datasets matches the international WMO/GAW recommendations. Time series from July 2014 to February 2020 were analysed. We inferred a mean annual growth rate at 100 m AGL of 2.7 ppm/year for CO2 (7.8 ppb/year for CH4) over the period of study, whereas no significant annual growth rate was found for CO. These growth rates are comparable to other remote ICOS and WMO/GAW sites. A seasonal amplitude of 13 ppm, 30 ppb, 45 ppb was found for atmospheric CO2, CH4 and CO, respectively. As expected, the amplitude of the diurnal cycle of these three species varies in function of the season, from 2.6 (1.6) ppm in winter and 10.7 (6.6) ppm in summer for CO2, 3.7 (5.1) and 7.7 (7.1) ppb for CH4, and contrary to CO2 and CH4 smaller amplitude in summer with 2.15 (2.5) ppb and 9.3 (8.9) ppb in winter for CO at 10 m (100 m) AGL. Significant correlations (R2 between 0.67 and 0.91) between the three species have been detected, especially in the winter season. Using thresholds on wind speed and on the standard variation of hourly concentrations, more than 16% of the data were identified to be enriched either: 1/by regional anthropogenic plumes; 2/during stable synoptic conditions inducing the accumulation of anthropogenic emissions in the atmospheric boundary layer (13%); and 3/by local's sources inducing short pollution events (3%). On average, $\Delta$CO/$\Delta$ CO2 ratios of 3.72 ± 0.06 ppb/ppm and 0.8 ± 0.2 ppb/ppm for $\Delta$ CH4/$\Delta$CO were inferred during local pollution events in winter and are typical of traffic and residential heating as given by the local bottom-up emissions inventory delivered by the regional air quality agency ATMOSUD. Adding specific tracers or isotopic measurements would be very interesting to distinguish anthropogenic sources and monitor the evolution of their characteristics as emission ratios at the OHP station. Filtering out these conditions, about 84% of the data are not undergoing the influence of local and regional anthropogenic plumes, and are thus representative of “background” CO2, CO and CH4 concentrations at the local to the regional scales. These background conditions are shown to be dependent on wind speed and direction.}, author = {Lelandais, L and Xueref-Remy, I and Riandet, A and Blanc, P E and Armengaud, A and Oppo, S and Yohia, C and Ramonet, M and Delmotte, M}, doi = {https://doi.org/10.1016/j.atmosenv.2022.119020}, issn = {1352-2310}, journal = {Atmospheric Environment}, keywords = { Enhancement ratio, ICOS, Observations, South France,Atmospheric greenhouse gases}, pages = {119020}, title = {{Analysis of 5.5 years of atmospheric CO2, CH4, CO continuous observations (2014–2020) and their correlations, at the Observatoire de Haute Provence, a station of the ICOS-France national greenhouse gases observation network}}, url = {https://www.sciencedirect.com/science/article/pii/S1352231022000851}, volume = {277}, year = {2022} } @article{acp-21-17907-2021, author = {Levin, I and Karstens, U and Hammer, S and DellaColetta, J and Maier, F and Gachkivskyi, M}, doi = {10.5194/acp-21-17907-2021}, journal = {Atmospheric Chemistry and Physics}, number = {23}, pages = {17907--17926}, title = {{Limitations of the radon tracer method (RTM) to estimate regional greenhouse gas (GHG) emissions -- a case study for methane in Heidelberg}}, url = {https://acp.copernicus.org/articles/21/17907/2021/}, volume = {21}, year = {2021} } @article{https://doi.org/10.1111/pce.14326, abstract = {Abstract Increasing temperature and drought can result in leaf dehydration and defoliation even in drought-adapted tree species such as the Mediterranean evergreen Quercus ilex L. The stomatal regulation of leaf water potential plays a central role in avoiding this phenomenon and is constrained by a suite of leaf traits including hydraulic conductance and vulnerability, hydraulic capacitance, minimum conductance to water vapour, osmotic potential and cell wall elasticity. We investigated whether the plasticity in these traits may improve leaf tolerance to drought in two long-term rainfall exclusion experiments in Mediterranean forests. Osmotic adjustment was observed to lower the water potential at turgor loss in the rainfall-exclusion treatments, thus suggesting a stomatal closure at more negative water potentials and a more anisohydric behaviour in drier conditions. Conversely, leaf hydraulic conductance and vulnerability did not exhibit any plasticity between treatments so the hydraulic safety margins were narrower in the rainfall-exclusion treatments. The sequence of leaf responses to seasonal drought and dehydration was conserved among treatments and sites but trees were more likely to suffer losses of turgor and hydraulic functioning in the rainfall-exclusion treatments. We conclude that leaf plasticity might help the trees to tolerate moderate drought but not to resist severe water stress.}, author = {Limousin, Jean-Marc and Roussel, Am{\'{e}}lie and Rodr{\'{i}}guez-Calcerrada, Jes{\'{u}}s and Torres-Ruiz, Jos{\'{e}} M and Moreno, Myriam and de Jalon, Laura and Ourcival, Jean-Marc and Simioni, Guillaume and Cochard, Herv{\'{e}} and Martin-StPaul, Nicolas}, doi = {https://doi.org/10.1111/pce.14326}, journal = {Plant, Cell \& Environment}, keywords = { hydraulic vulnerability, osmotic adjustment, plasticity, rainfall exclusion, safety margin, stomatal regulation, turgor loss, water potential,evergreen broadleaf}, number = {7}, pages = {1967--1984}, title = {{Drought acclimation of Quercus ilex leaves improves tolerance to moderate drought but not resistance to severe water stress}}, url = {https://onlinelibrary.wiley.com/doi/abs/10.1111/pce.14326}, volume = {45}, year = {2022} } @article{LINDBERG2022124817, abstract = {The temporal correlation between different power generation sources is important for quantifying the reduction in variability when constructing co-located hybrid power parks (HPPs) that combine multiple power sources. This study investigates the physical mechanisms behind correlation on time scales relevant for the power system using frequency separated time scales. The methodology is universally applicable to any data set consisting of at least two power sources and could be adjusted accordingly. The methodology is demonstrated and validated in a case study across Sweden for wind and PV power generation, using the meteorological reanalysis dataset CosmoREA-6. All studied time-scales (seasonal, mid-term, synoptic and diurnal) showed anti-correlated characteristics, although the magnitude of temporal correlation is highly dependent on the time-scale considered. The highest potential for useful anti-correlation is found on the seasonal cycle, followed by the diurnal cycle where existing wind turbine sites, on average, have stronger anti-correlation than the average site. The validation showed good correspondence with measurements for all time-scales. However, an underestimations of the results were found for the diurnal and seasonal cycle while this was shown to have a minor effect when analyzing the correlation on different time scales. The methodology of the case study should be generally valid for all similar climates.}, author = {Lindberg, O and Lingfors, D and Arnqvist, J}, doi = {https://doi.org/10.1016/j.energy.2022.124817}, issn = {0360-5442}, journal = {Energy}, keywords = { PV power, Reanalysis product, Site assessment, Temporal correlation, Wind power,Hybrid power park}, pages = {124817}, title = {{Analyzing the mechanisms behind temporal correlation between power sources using frequency separated time scales: A Swedish case study on PV and wind}}, url = {https://www.sciencedirect.com/science/article/pii/S0360544222017200}, volume = {259}, year = {2022} } @article{bg-19-4747-2022, author = {Linkosalmi, M and Tuovinen, J.-P. and Nevalainen, O and Peltoniemi, M and Tani\cs, C M and Arslan, A N and Rainne, J and Lohila, A and Laurila, T and Aurela, M}, doi = {10.5194/bg-19-4747-2022}, journal = {Biogeosciences}, number = {19}, pages = {4747--4765}, title = {{Tracking vegetation phenology of pristine northern boreal peatlands by combining digital photography with CO$_{2}$ flux and remote sensing data}}, url = {https://bg.copernicus.org/articles/19/4747/2022/}, volume = {19}, year = {2022} } @article{LIU2022109095, abstract = {Vegetation phenology is a sensitive indicator of ecosystem responses to climate change, and thus the accurate estimation of vegetation phenology is critical to evaluate the impact of climate change on terrestrial ecosystems. Common structural vegetation indices (VIs) such as the Normalized Difference Vegetation Index (NDVI), Enhanced Vegetation Index (EVI), Near-infrared Reflectance of Vegetation (NIRv) and Plant Phenology Index (PPI), are the most widely used indicators of phenology, but they have limited potential in tracking autumn phenology, especially for evergreen species with low seasonal variability of canopy greenness. Given the important role of carotenoid pigments in regulating photosynthetic activity and plant phenology, we hypothesize that satellite-based indicators of leaf pigments derived from MODIS ocean bands could be useful for phenology modeling. Using 624 site-years of flux data at 84 FLUXNET sites and 9979 ground observations at 138 PEP725 sites, we first explored the potential of different forms of scaled photochemical reflectance index (sPRIref) in monitoring photosynthetic activity, and found that band 10 and band 13 were more suitable for tracking gross primary productivity (GPP) than other reference bands. By comparing with canopy photosynthetic phenology, sPRI10 and sPRI13 showed improved representation of phenological transitions (the start and end of growing season, SOS and EOS, respectively) than structural VIs. In spring, all VIs exhibited comparable performances for estimating SOS at deciduous broadleaf forests (DBF) and grasslands (GRA) sites; however, sPRI10 and sPRI13 were better predictors of SOS than structural VIs at evergreen needleleaf forests (ENF) and mixed forests (MF) sites. In autumn, sPRI10 and sPRI13 showed improved predictive strength of EOS than structural VIs for ENF, MF and GRA sites. Further investigations using the ground observed phenological records also confirmed the improved performances of sPRI10 and sPRI13 for both SOS and EOS estimation. We also investigated the spatial patterns of sPRI10-derived SOS and EOS over the Northern Hemisphere with respect to different plant functional types. We showed that sPRI10 reliably tracked plant phenology with 83.0% and 78.8% success in detecting SOS and EOS, respectively. Spatial patterns of SOS exhibited obvious latitudinal gradients, while EOS showed a strong regional heterogeneity. In addition, sPRI10 predicted an overall earlier SOS (61.8%) and later EOS (51.2%) than the MODIS phenology product (VNP22Q2 v001) estimated from structural VI, suggesting the latter underestimated the greening potential of the Northern Hemisphere. Our results suggest that MODIS PRI could be useful to monitor vegetation phenology, and further reveal the importance of underappreciated carotenoid pigments in tracking plant seasonal changes, particularly in autumn months.}, author = {Liu, Ying and Wu, Chaoyang and Tian, Feng and Wang, Xiaoyue and Gamon, John A and Wong, Christopher Y S and Zhang, Xiaoyang and Gonsamo, Alemu and Jassal, Rachhpal S}, doi = {https://doi.org/10.1016/j.agrformet.2022.109095}, issn = {0168-1923}, journal = {Agricultural and Forest Meteorology}, keywords = { EVI, Gross Primary Productivity, NDVI, Photochemical Reflectance Index,Phenology}, pages = {109095}, title = {{Modeling plant phenology by MODIS derived photochemical reflectance index (PRI)}}, url = {https://www.sciencedirect.com/science/article/pii/S0168192322002830}, volume = {324}, year = {2022} } @article{LUCASMOFFAT2022109114, abstract = {With novel developments in technology, eddy covariance flux measurements have become feasible for a variety of trace gases. While the statistical properties and gap-filling strategies have been well examined for carbon dioxide, these are much less understood for other gases. Here, we propose a universal methodology deploying multiple gap-filling techniques and artificial gap scenarios to evaluate the techniques' performances, infer the statistical flux properties, and fill the real gaps in eddy covariance datasets of any trace gas. The methodology was implemented in a gap-filling framework with techniques spanning from simple and diurnal interpolations, look-up tables, artificial neural networks, to an inferential model. For the new scheme of half-hourly and daily artificial gaps, each additional gap was superimposed one at a time (thus keeping the disturbance to a minimum) for the whole dataset and the scenarios were resampled by bootstrapping. The gap-filled sums were then estimated from the ensemble of well-performing gap-filling techniques. The gap-filling framework was applied to campaign data of three different trace gases (51 days of ammonia, 79 days of total reactive nitrogen, and 89 days of methane flux measurements). The aggregated fluxes are stated as ensemble ranges of multiple techniques plus the techniques' uncertainties. Additionally, the framework was used to gap-fill a full year of carbon dioxide flux measurements yielding similar performances as previously reported. Based on a review of gap-filling comparison studies and on our findings, we suggest reconsidering the standard procedure of using one gap-filling technique for multi-site studies. Deploying multiple gap-filling techniques and providing ensemble results of gap-filled sums will help to minimize the influence of a single technique and thus lead to a more robust flux aggregation. Furthermore, the estimated overall uncertainty will be more realistic by accounting for the ensemble range of multiple techniques.}, author = {Lucas-Moffat, Antje M and Schrader, Frederik and Herbst, Mathias and Br{\"{u}}mmer, Christian}, doi = {https://doi.org/10.1016/j.agrformet.2022.109114}, issn = {0168-1923}, journal = {Agricultural and Forest Meteorology}, keywords = { artificial gap scenarios, bootstrapping, ensemble results, multiple gap-filling, trace gases,Eddy covariance fluxes}, pages = {109114}, title = {{Multiple gap-filling for eddy covariance datasets}}, url = {https://www.sciencedirect.com/science/article/pii/S016819232200301X}, volume = {325}, year = {2022} } @article{MaLu2022, abstract = {Decomposition models of solar irradiance estimate the magnitude of diffuse horizontal irradiance from global horizontal irradiance. These two radiation components are well known to be essential for predicting the performance of solar photovoltaic systems. In open-field agrivoltaic systems (i.e., the dual use of land for both agricultural activities and solar power conversion), cultivated crops receive unequal amounts of direct, diffuse, and reflected photosynthetically active radiation (PAR). These uneven amounts depend on where the crops are growing due to the non-homogenous shadings caused by the presence of the installed solar panels (above the crops or vertically mounted). It is known that, per unit of total PAR, diffuse PAR is more efficient for canopy photosynthesis than is direct PAR. For this reason, it is essential to estimate the diffuse PAR component when agrivoltaic systems are being assessed, in order to properly predict the crop yield. Since PAR is the electromagnetic radiation in the 400–700 nm waveband that can be used for photosynthesis by the crops, several stand-alone decomposition models typically used to split global horizontal irradiance are selected in this study to decompose PAR into direct and diffuse. These models are applied and validated in three locations in Sweden (Lanna, Hyltemossa and Norunda) using the coefficients stated on the models' original publications and locally fitted coefficients. The results showed weaker performances in all stand-alone models for non-locally fitted coefficients (nRMSE ranging from 27% to 43%). However, performances improve with re-parameterization, with a highest nRMSE of 35.24% in Lanna. The Yang2 decomposition model is the best-performing one, with the lowest nRMSE of 23.75% in Norunda when applying re-estimated coefficients. Country level sets of coefficients for the best-performing models (Yang2 and Starke) are given after parameterization using combined data for all three locations in Sweden. These Sweden-fitted models are tested and show an nRMSE of 25.08% (Yang2) and 28.60% (Starke). These results can be used to perform estimations of the PAR diffuse component in Sweden wherever ground measurements are not available. The overall methodology can be similarly applied to other countries.}, author = {{Ma Lu}, S and Zainali, S and Stridh, B and Avelin, A and Amaducci, S and Colauzzi, M and Campana, P E}, doi = {https://doi.org/10.1016/j.solener.2022.05.046}, issn = {0038-092X}, journal = {Solar Energy}, keywords = {Agrivoltaic,Decomposition models,Diffuse fraction,Integrated Carbon Observation System,Photosynthetically active radiation}, pages = {536--549}, title = {{Photosynthetically active radiation decomposition models for agrivoltaic systems applications}}, url = {https://www.sciencedirect.com/science/article/pii/S0038092X22003917}, volume = {244}, year = {2022} } @article{MALU2022536, abstract = {Decomposition models of solar irradiance estimate the magnitude of diffuse horizontal irradiance from global horizontal irradiance. These two radiation components are well known to be essential for predicting the performance of solar photovoltaic systems. In open-field agrivoltaic systems (i.e., the dual use of land for both agricultural activities and solar power conversion), cultivated crops receive unequal amounts of direct, diffuse, and reflected photosynthetically active radiation (PAR). These uneven amounts depend on where the crops are growing due to the non-homogenous shadings caused by the presence of the installed solar panels (above the crops or vertically mounted). It is known that, per unit of total PAR, diffuse PAR is more efficient for canopy photosynthesis than is direct PAR. For this reason, it is essential to estimate the diffuse PAR component when agrivoltaic systems are being assessed, in order to properly predict the crop yield. Since PAR is the electromagnetic radiation in the 400–700 nm waveband that can be used for photosynthesis by the crops, several stand-alone decomposition models typically used to split global horizontal irradiance are selected in this study to decompose PAR into direct and diffuse. These models are applied and validated in three locations in Sweden (Lanna, Hyltemossa and Norunda) using the coefficients stated on the models' original publications and locally fitted coefficients. The results showed weaker performances in all stand-alone models for non-locally fitted coefficients (nRMSE ranging from 27% to 43%). However, performances improve with re-parameterization, with a highest nRMSE of 35.24% in Lanna. The Yang2 decomposition model is the best-performing one, with the lowest nRMSE of 23.75% in Norunda when applying re-estimated coefficients. Country level sets of coefficients for the best-performing models (Yang2 and Starke) are given after parameterization using combined data for all three locations in Sweden. These Sweden-fitted models are tested and show an nRMSE of 25.08% (Yang2) and 28.60% (Starke). These results can be used to perform estimations of the PAR diffuse component in Sweden wherever ground measurements are not available. The overall methodology can be similarly applied to other countries.}, author = {{Ma Lu}, S and Zainali, S and Stridh, B and Avelin, A and Amaducci, S and Colauzzi, M and Campana, P E}, doi = {https://doi.org/10.1016/j.solener.2022.05.046}, issn = {0038-092X}, journal = {Solar Energy}, keywords = { Decomposition models, Diffuse fraction, Integrated Carbon Observation System, Photosynthetically active radiation,Agrivoltaic}, pages = {536--549}, title = {{Photosynthetically active radiation decomposition models for agrivoltaic systems applications}}, url = {https://www.sciencedirect.com/science/article/pii/S0038092X22003917}, volume = {244}, year = {2022} } @article{TheSeaSurfaceHeatFluxataCoastalSite, address = {Boston MA, USA}, author = {Mahrt, L and Nilsson, Erik and Rutgersson, Anna}, doi = {10.1175/JPO-D-22-0094.1}, journal = {Journal of Physical Oceanography}, number = {12}, pages = {3297--3307}, publisher = {American Meteorological Society}, title = {{The Sea Surface Heat Flux at a Coastal Site}}, url = {https://journals.ametsoc.org/view/journals/phoc/52/12/JPO-D-22-0094.1.xml}, volume = {52}, year = {2022} } @article{gmd-15-5391-2022, author = {Maier, F and Gerbig, C and Levin, I and Super, I and Marshall, J and Hammer, S}, doi = {10.5194/gmd-15-5391-2022}, journal = {Geoscientific Model Development}, number = {13}, pages = {5391--5406}, title = {{Effects of point source emission heights in WRF--STILT: a step towards exploiting nocturnal observations in models}}, url = {https://gmd.copernicus.org/articles/15/5391/2022/}, volume = {15}, year = {2022} } @article{MAIER2022157541, abstract = {Agriculture contributes considerably to the increase of global greenhouse gas (GHG) emissions. Hence, magnitude and drivers of temporal variations in carbon dioxide (CO2), nitrous oxide (N2O) and methane (CH4) fluxes in croplands are urgently needed to develop sustainable, climate-smart agricultural practices. However, our knowledge of GHG fluxes from croplands is still very limited. The eddy covariance technique was used to quantify GHG budgets and N2O emission factors (EF) for pea and maize in Switzerland. The random forest technique was applied for gap-filling N2O and CH4 fluxes as well as to determine the relevance of environmental, vegetation vs. management drivers of the GHG fluxes during two cropping seasons. Environmental (i.e., net radiation, soil water content, soil temperature) and vegetation drivers (i.e., vegetation height) were more important drivers for GHG fluxes at field scale than time since management for the two crop species. Both crops acted as GHG sinks between sowing and harvest, clearly dominated by net CO2 fluxes, while CH4 emissions were negligible. However, considerable N2O emissions occurred in both crop fields early in the season when crops were still establishing. N2O fluxes in both crops were small later in the season when vegetation was tall, despite high soil water contents and temperatures. Results clearly show a strong and highly dynamic microbial-plant competition for N driving N2O fluxes at the field scale. The total loss was 1.4 kg N2O-N ha−1 over 55 days for pea and 4.8 kg N2O-N ha−1 over 127 days for maize. EFs of N2O were 1.5 % (pea) and 4.4 % (maize) during the cropping seasons, clearly exceeding the IPCC Tier 1 EF for N2O. Thus, sustainable, climate-smart agriculture needs to consider crop phenology and better adapt N supply to crop N demand for growth, particularly during the early cropping season when competition for N between establishing crops and soil microorganisms modulates N2O losses.}, author = {Maier, Regine and H{\"{o}}rtnagl, Lukas and Buchmann, Nina}, doi = {https://doi.org/10.1016/j.scitotenv.2022.157541}, issn = {0048-9697}, journal = {Science of The Total Environment}, keywords = { Agriculture, Arable land, Eddy covariance, Legume, Management,Corn}, pages = {157541}, title = {{Greenhouse gas fluxes (CO2, N2O and CH4) of pea and maize during two cropping seasons: Drivers, budgets, and emission factors for nitrous oxide}}, url = {https://www.sciencedirect.com/science/article/pii/S0048969722046393}, volume = {849}, year = {2022} } @article{MAKI2022108876, abstract = {Northern forest soils are a major carbon (C) reservoir of global importance. To estimate how the C balance in these soils will change, the roles of tree roots and soil microbes in C balance should first be decoupled. This study determined how the activity of heterotrophs and tree roots together with root-associated microbes in the rhizosphere varies in coniferous forest soils in boreal, hemiboreal, and temperate climates along a latitudinal gradient using a trenching approach. We created experimental plots without living tree roots, measured soil respiration (CO2 efflux) from these and from unmanipulated plots using the chamber technique, and partitioned the efflux into root-rhizosphere (RR) and heterotrophic (RH) respiration. The share of RR in ecosystem gross primary production (GPP) decreased from north to south in the Scots pine (Pinus sylvestris L.) and the Norway spruce (Picea abies (L.) Karst.) forests, with the exception of a mixed site, where the share of RR in GPP varied strongly between the years. RR per ground area and per root biomass were mainly independent of climate within the gradient. RH per ground area increased from north to south with temperature, while RH per soil C did not change with temperature. Soil moisture did not significantly affect the respiration components in the northernmost site, whereas soil moisture was positively connected with RH and negatively with RR in other Scots pine sites and positively connected with RR in pure Norway spruce stands. The dynamic ecosystem model LPJ-GUESS was able to capture the seasonal dynamics of RH and RR at the sites, but overall accuracy varied markedly between the sites, as the model underestimated RH in the southern site and RR elsewhere. Our study provides knowledge about the nature of soil respiration components. The valuable insights can be used in more accurate land-ecosystem modelling of forest ecosystems.}, author = {M{\"{a}}ki, Mari and Ryhti, Kira and Fer, Istem and Ťupek, Boris and Vestin, Patrik and Roland, Marilyn and Lehner, Irene and K{\"{o}}ster, Egle and Lehtonen, Aleksi and B{\"{a}}ck, Jaana and Heinonsalo, Jussi and Pumpanen, Jukka and Kulmala, Liisa}, doi = {https://doi.org/10.1016/j.agrformet.2022.108876}, issn = {0168-1923}, journal = {Agricultural and Forest Meteorology}, keywords = { CO2 efflux, Carbon cycle, Forest soil, Land-surface modelling, Norway spruce, Scots pine, Soil carbon, Soil respiration, Trenching,Chamber measurements}, pages = {108876}, title = {{Heterotrophic and rhizospheric respiration in coniferous forest soils along a latitudinal gradient}}, url = {https://www.sciencedirect.com/science/article/pii/S0168192322000697}, volume = {317}, year = {2022} } @article{MARTINEZGARCIA2022108916, abstract = {The forest-floor represents an important interface for various carbon dioxide (CO2) fluxes, however, our knowledge of their variability and drivers across a managed boreal forest landscape is limited. Here, we used a three-year (2016−2018) data set of biometric- and chamber-based flux measurements to investigate the net forest-floor CO2 exchange (NEff) and its component fluxes across 50 forest stands spanning different soil types, tree species, and age classes within a 68 km2 boreal catchment in Sweden. We found that the forest-floor acted as a net CO2 source with the 10th–90th percentile (used hereafter for describing reported variations) ranging from 149 to 399 g C m−2 yr−1. Among the key landscape attributes, stand age strongly affected most NEff component fluxes, whereas tree species and soil type effects were weak and absent, respectively. Specifically, forest-floor net CO2 emissions increased with stand age due to declining understory gross and net primary production, ranging between 77–275 and 49–163 g C m−2 yr−1, respectively. Furthermore, we observed higher understory production rates in pine than in spruce stands. Across the 50 stands, the total forest-floor respiration ranged between 340 and 549 g C m−2 yr−1 and its spatial variation was primarily regulated by its autotrophic components, i.e., understory and tree root respiration, which displayed divergent increasing and decreasing age-related trends, respectively. Furthermore, heterotrophic soil respiration remained within a relatively narrow range (154–290 g C m−2 yr−1), possibly owing to compensating gradients in forest-floor properties. We further identified tree biomass as the major driver of the landscape-scale variations of CO2 fluxes, likely attributable to modulating effects on forest-floor resource availability and growing conditions. This implies that tree growth responses to forest management and global change will be particularly important for regulating magnitudes and spatial variations of forest-floor CO2 fluxes in boreal forests.}, author = {Mart{\'{i}}nez-Garc{\'{i}}a, Eduardo and Nilsson, Mats B and Laudon, Hjalmar and Lundmark, Tomas and Fransson, Johan E S and Wallerman, J{\"{o}}rgen and Peichl, Matthias}, doi = {https://doi.org/10.1016/j.agrformet.2022.108916}, issn = {0168-1923}, journal = {Agricultural and Forest Meteorology}, keywords = { Carbon dioxide exchange, Forest-floor, Landscape variability, Primary production, Respiration,Boreal forest}, pages = {108916}, title = {{Overstory dynamics regulate the spatial variability in forest-floor CO2 fluxes across a managed boreal forest landscape}}, url = {https://www.sciencedirect.com/science/article/pii/S0168192322001095}, volume = {318}, year = {2022} } @article{Martinez2021, abstract = {Continued developments in instrumentation and modeling have driven progress in monitoring methane (CH4 ) emissions at a range of spatial scales. The sites that emit CH4 such as landfills, oil and gas extraction or storage infrastructure, intensive livestock farms account for a large share of global emissions, and need to be monitored on a continuous basis to verify the effectiveness of reductions policies. Low cost sensors are valuable to monitor methane (CH4 ) around such facilities because they can be deployed in a large number to sample atmospheric plumes and retrieve emission rates using dispersion models. Here we present two tests of three different versions of Figaro{\textregistered} TGS tin-oxide sensors for estimating CH4 concentrations variations, at levels similar to current atmospheric values, with a sought accuracy of 0.1 to 0.2 ppm. In the first test, we characterize the variation of the resistance of the tin-oxide semi-conducting sensors to controlled levels of CH4, H2 O and CO in the laboratory, to analyze cross-sensitivities. In the second test, we reconstruct observed CH4 variations in a room, that ranged from 1.9 and 2.4 ppm during a three month experiment from observed time series of resistances and other variables. To do so, a machine learning model is trained against true CH4 recorded by a high precision instrument. The machine-learning model using 30% of the data for training reconstructs CH4 within the target accuracy of 0.1 ppm only if training variables are representative of conditions during the testing period. The model-derived sensitivities of the sensors resistance to H2 O compared to CH4 are larger than those observed under controlled conditions, which deserves further characterization of all the factors influencing the resistance of the sensors.}, author = {Martinez, Rodrigo Rivera and Santaren, Diego and Laurent, Olivier and Cropley, Ford and Mallet, C{\'{e}}cile and Ramonet, Michel and Caldow, Christopher and Rivier, Leonard and Broquet, Gregoire and Bouchet, Caroline and Juery, Catherine and Ciais, Philippe}, doi = {10.3390/atmos12010107}, file = {:Users/villekasurinen/Downloads/atmosphere-12-00107-v2.pdf:pdf}, issn = {20734433}, journal = {Atmosphere}, keywords = {Artificial neural networks,Calibration,Low-cost sensors,Methane}, number = {1}, pages = {1--22}, title = {{The potential of low-cost tin-oxide sensors combined with machine learning for estimating atmospheric ch4 variations around background concentration}}, volume = {12}, year = {2021} } @article{https://doi.org/10.1111/gcb.16189, abstract = {Abstract Reconstructions of past climate impact, that is, radiative forcing (RF), of peatland carbon (C) dynamics show that immediately after peatland initiation the climate warming effect of CH4 emissions exceeds the cooling effect of CO2 uptake, but thereafter the net effect of most peatlands will move toward cooling, when RF switches from positive to negative. Reconstructing peatland C dynamics necessarily involves uncertainties related to basic assumptions on past CO2 flux, CH4 emission and peatland expansion. We investigated the effect of these uncertainties on the RF of three peatlands, using either apparent C accumulation rates, net C balance (NCB) or NCB plus C loss during fires as basis for CO2 uptake estimate; applying a plausible range for CH4 emission; and assuming linearly interpolated expansion between basal dates or comparatively early or late expansion. When we factored that some C would only be stored temporarily (NCB and NCB+fire), the estimated past cooling effect of CO2 uptake increased, but the present-day RF was affected little. Altering the assumptions behind the reconstructed CO2 flux or expansion patterns caused the RF to peak earlier and advanced the switch from positive to negative RF by several thousand years. Compared with NCB, including fires had only small additional effect on RF lasting less than 1000 year. The largest uncertainty in reconstructing peatland RF was associated with CH4 emissions. As shown by the consistently positive RF modelled for one site, and in some cases for the other two, peatlands with high CH4 emissions and low C accumulation rates may have remained climate warming agents since their initiation. Although uncertainties in present-day RF were mainly due to the assumed CH4 emission rates, the uncertainty in lateral expansion still had a significant effect on the present-day RF, highlighting the importance to consider uncertainties in the past peatland C balance in RF reconstructions.}, author = {Mathijssen, Paul J H and Tuovinen, Juha-Pekka and Lohila, Annalea and V{\"{a}}liranta, Minna and Tuittila, Eeva-Stiina}, doi = {https://doi.org/10.1111/gcb.16189}, journal = {Global Change Biology}, keywords = { Holocene, lateral expansion, net carbon balance, peatland fires, peatland-climate feedback, radiative forcing,greenhouse gas balance}, number = {13}, pages = {4069--4084}, title = {{Identifying main uncertainties in estimating past and present radiative forcing of peatlands}}, url = {https://onlinelibrary.wiley.com/doi/abs/10.1111/gcb.16189}, volume = {28}, year = {2022} } @article{https://doi.org/10.1111/gcb.16332, abstract = {Abstract Central Europe has been experiencing unprecedented droughts during the last decades, stressing the decrease in tree water availability. However, the assessment of physiological drought stress is challenging, and feedback between soil and vegetation is often omitted because of scarce belowground data. Here we aimed to model Swiss forests' water availability during the 2015 and 2018 droughts by implementing the mechanistic soil-vegetation-atmosphere-transport (SVAT) model LWF-Brook90 taking advantage of regionalized depth-resolved soil information. We calibrated the model against soil matric potential data measured from 2014 to 2018 at 44 sites along a Swiss climatic and edaphic drought gradient. Swiss forest soils' storage capacity of plant-available water ranged from 53 mm to 341 mm, with a median of 137 ± 42 mm down to the mean potential rooting depth of 1.2 m. Topsoil was the primary water source. However, trees switched to deeper soil water sources during drought. This effect was less pronounced for coniferous trees with a shallower rooting system than for deciduous trees, which resulted in a higher reduction of actual transpiration (transpiration deficit) in coniferous trees. Across Switzerland, forest trees reduced the transpiration by 23\% (compared to potential transpiration) in 2015 and 2018, maintaining annual actual transpiration comparable to other years. Together with lower evaporative fluxes, the Swiss forests did not amplify the blue water deficit. The 2018 drought, characterized by a higher and more persistent transpiration deficit than in 2015, triggered widespread early wilting across Swiss forests that was better predicted by the SVAT-derived mean soil matric potential in the rooting zone than by climatic predictors. Such feedback-driven quantification of ecosystem water fluxes in the soil–plant-atmosphere continuum will be crucial to predicting physiological drought stress under future climate extremes.}, author = {Meusburger, Katrin and Trotsiuk, Volodymyr and Schmidt-Walter, Paul and Baltensweiler, Andri and Brun, Philipp and Bernhard, Fabian and Gharun, Mana and Habel, Raphael and Hagedorn, Frank and K{\"{o}}chli, Roger and Psomas, Achilleas and Puhlmann, Heike and Thimonier, Anne and Waldner, Peter and Zimmermann, Stephan and Walthert, Lorenz}, doi = {https://doi.org/10.1111/gcb.16332}, journal = {Global Change Biology}, keywords = { European summer drought, physiological drought, plant-available water storage capacity, root water uptake, water balance,climate impact}, number = {20}, pages = {5928--5944}, title = {{Soil–plant interactions modulated water availability of Swiss forests during the 2015 and 2018 droughts}}, url = {https://onlinelibrary.wiley.com/doi/abs/10.1111/gcb.16332}, volume = {28}, year = {2022} } @article{acp-2022-510, author = {Munassar, S and Monteil, G and Scholze, M and Karstens, U and R{\"{o}}denbeck, C and Koch, F.-T. and Totsche, K U and Gerbig, C}, doi = {10.5194/acp-2022-510}, journal = {Atmospheric Chemistry and Physics Discussions}, pages = {1--26}, title = {{Impact of atmospheric transport on CO$_2$ flux estimates derived from the atmospheric tracer inversions}}, url = {https://acp.copernicus.org/preprints/acp-2022-510/}, volume = {2022}, year = {2022} } @article{acp-22-7875-2022, author = {Munassar, S and R{\"{o}}denbeck, C and Koch, F.-T. and Totsche, K U and Ga{\l}kowski, M and Walther, S and Gerbig, C}, doi = {10.5194/acp-22-7875-2022}, journal = {Atmospheric Chemistry and Physics}, number = {12}, pages = {7875--7892}, title = {{Net ecosystem exchange (NEE) estimates 2006--2019 over Europe from a pre-operational ensemble-inversion system}}, url = {https://acp.copernicus.org/articles/22/7875/2022/}, volume = {22}, year = {2022} } @article{NICOLINI2022154662, abstract = {The measures taken to contain the spread of COVID-19 in 2020 included restrictions of people's mobility and reductions in economic activities. These drastic changes in daily life, enforced through national lockdowns, led to abrupt reductions of anthropogenic CO2 emissions in urbanized areas all over the world. To examine the effect of social restrictions on local emissions of CO2, we analysed district level CO2 fluxes measured by the eddy-covariance technique from 13 stations in 11 European cities. The data span several years before the pandemic until October 2020 (six months after the pandemic began in Europe). All sites showed a reduction in CO2 emissions during the national lockdowns. The magnitude of these reductions varies in time and space, from city to city as well as between different areas of the same city. We found that, during the first lockdowns, urban CO2 emissions were cut with respect to the same period in previous years by 5% to 87% across the analysed districts, mainly as a result of limitations on mobility. However, as the restrictions were lifted in the following months, emissions quickly rebounded to their pre-COVID levels in the majority of sites.}, author = {Nicolini, Giacomo and Antoniella, Gabriele and Carotenuto, Federico and Christen, Andreas and Ciais, Philippe and Feigenwinter, Christian and Gioli, Beniamino and Stagakis, Stavros and Velasco, Erik and Vogt, Roland and Ward, Helen C and Barlow, Janet and Chrysoulakis, Nektarios and Duce, Pierpaolo and Graus, Martin and Helfter, Carole and Heusinkveld, Bert and J{\"{a}}rvi, Leena and Karl, Thomas and Marras, Serena and Masson, Val{\'{e}}ry and Matthews, Bradley and Meier, Fred and Nemitz, Eiko and Sabbatini, Simone and Scherer, Dieter and Schume, Helmut and Sirca, Costantino and Steeneveld, Gert-Jan and Vagnoli, Carolina and Wang, Yilong and Zaldei, Alessandro and Zheng, Bo and Papale, Dario}, doi = {https://doi.org/10.1016/j.scitotenv.2022.154662}, issn = {0048-9697}, journal = {Science of The Total Environment}, keywords = { Corona virus pandemic, Social restrictions, Traffic emissions, Urban fluxes, Urban pollution,Eddy-covariance}, pages = {154662}, title = {{Direct observations of CO2 emission reductions due to COVID-19 lockdown across European urban districts}}, url = {https://www.sciencedirect.com/science/article/pii/S0048969722017557}, volume = {830}, year = {2022} } @article{Niu2021, abstract = {Warming-induced carbon loss through terrestrial ecosystem respiration (Re) is likely getting stronger in high latitudes and cold regions because of the more rapid warming and higher temperature sensitivity of Re (Q10). However, it is not known whether the spatial relationship between Q10 and temperature also holds temporally under a future warmer climate. Here, we analyzed apparent Q10 values derived from multiyear observations at 74 FLUXNET sites spanning diverse climates and biomes. We found warming-induced decline in Q10 is stronger at colder regions than other locations, which is consistent with a meta-analysis of 54 field warming experiments across the globe. We predict future warming will shrink the global variability of Q10 values to an average of 1.44 across the globe under a high emission trajectory (RCP 8.5) by the end of the century. Therefore, warming-induced carbon loss may be less than previously assumed because of Q10 homogenization in a warming world.}, author = {Niu, Ben and Zhang, Xianzhou and Piao, Shilong and Janssens, Ivan A. and Fu, Gang and He, Yongtao and Zhang, Yangjian and Shi, Peili and Dai, Erfu and Yu, Chengqun and Zhang, Jing and Yu, Guirui and Xu, Ming and Wu, Jianshuang and Zhu, Liping and Desai, Ankur R. and Chen, Jiquan and Bohrer, Gil and Gough, Christopher M. and Mammarella, Ivan and Varlagin, Andrej and Fares, Silvano and Zhao, Xinquan and Li, Yingnian and Wang, Huiming and Ouyang, Zhu}, doi = {10.1126/SCIADV.ABC7358}, file = {:Users/villekasurinen/Downloads/eabc7358.full.pdf:pdf}, issn = {23752548}, journal = {Science Advances}, number = {15}, pmid = {33837072}, title = {{Warming homogenizes apparent temperature sensitivity of ecosystem respiration}}, volume = {7}, year = {2021} } @article{Oehri2022, abstract = {Despite the importance of high-latitude surface energy budgets (SEBs) for land-climate interactions in the rapidly changing Arctic, uncertainties in their prediction persist. Here, we harmonize SEB observations across a network of vegetated and glaciated sites at circumpolar scale (1994–2021). Our variance-partitioning analysis identifies vegetation type as an important predictor for SEB-components during Arctic summer (June-August), compared to other SEB-drivers including climate, latitude and permafrost characteristics. Differences among vegetation types can be of similar magnitude as between vegetation and glacier surfaces and are especially high for summer sensible and latent heat fluxes. The timing of SEB-flux summer-regimes (when daily mean values exceed 0 Wm−2) relative to snow-free and -onset dates varies substantially depending on vegetation type, implying vegetation controls on snow-cover and SEB-flux seasonality. Our results indicate complex shifts in surface energy fluxes with land-cover transitions and a lengthening summer season, and highlight the potential for improving future Earth system models via a refined representation of Arctic vegetation types.}, author = {Oehri, Jacqueline and Schaepman-Strub, Gabriela and Kim, Jin Soo and Grysko, Raleigh and Kropp, Heather and Gr{\"{u}}nberg, Inge and Zemlianskii, Vitalii and Sonnentag, Oliver and Euskirchen, Eug{\'{e}}nie S. and {Reji Chacko}, Merin and Muscari, Giovanni and Blanken, Peter D. and Dean, Joshua F. and di Sarra, Alcide and Harding, Richard J. and Sobota, Ireneusz and Kutzbach, Lars and Plekhanova, Elena and Riihel{\"{a}}, Aku and Boike, Julia and Miller, Nathaniel B. and Beringer, Jason and L{\'{o}}pez-Blanco, Efr{\'{e}}n and Stoy, Paul C. and Sullivan, Ryan C. and Kejna, Marek and Parmentier, Frans Jan W. and Gamon, John A. and Mastepanov, Mikhail and Wille, Christian and Jackowicz-Korczynski, Marcin and Karger, Dirk N. and Quinton, William L. and Putkonen, Jaakko and van As, Dirk and Christensen, Torben R. and Hakuba, Maria Z. and Stone, Robert S. and Metzger, Stefan and Vandecrux, Baptiste and Frost, Gerald V. and Wild, Martin and Hansen, Birger and Meloni, Daniela and Domine, Florent and te Beest, Mariska and Sachs, Torsten and Kalhori, Aram and Rocha, Adrian V. and Williamson, Scott N. and Morris, Sara and Atchley, Adam L. and Essery, Richard and Runkle, Benjamin R.K. and Holl, David and Riihimaki, Laura D. and Iwata, Hiroki and Schuur, Edward A.G. and Cox, Christopher J. and Grachev, Andrey A. and McFadden, Joseph P. and Fausto, Robert S. and G{\"{o}}ckede, Mathias and Ueyama, Masahito and Pirk, Norbert and de Boer, Gijs and Bret-Harte, M. Syndonia and Lepp{\"{a}}ranta, Matti and Steffen, Konrad and Friborg, Thomas and Ohmura, Atsumu and Edgar, Colin W. and Olofsson, Johan and Chambers, Scott D.}, doi = {10.1038/s41467-022-34049-3}, file = {:Users/villekasurinen/Downloads/s41467-022-34049-3.pdf:pdf}, isbn = {4146702234049}, issn = {20411723}, journal = {Nature Communications}, number = {1}, pages = {21--27}, pmid = {36316310}, title = {{Vegetation type is an important predictor of the arctic summer land surface energy budget}}, volume = {13}, year = {2022} } @article{acp-22-8097-2022, author = {Olin, M and Okuljar, M and Rissanen, M P and Kalliokoski, J and Shen, J and Dada, L and Lampim{\"{a}}ki, M and Wu, Y and Lohila, A and Duplissy, J and Sipil{\"{a}}, M and Pet{\"{a}}j{\"{a}}, T and Kulmala, M and {Dal Maso}, M}, doi = {10.5194/acp-22-8097-2022}, journal = {Atmospheric Chemistry and Physics}, number = {12}, pages = {8097--8115}, title = {{Measurement report: Atmospheric new particle formation in a coastal agricultural site explained with binPMF analysis of nitrate CI-APi-TOF spectra}}, url = {https://acp.copernicus.org/articles/22/8097/2022/}, volume = {22}, year = {2022} } @article{doi:10.1080/15481603.2022.2152303, author = {Pang, Yuwen and R{\"{a}}s{\"{a}}nen, Aleksi and Lindholm, Viivi and Aurela, Mika and Virtanen, Tarmo}, doi = {10.1080/15481603.2022.2152303}, journal = {GIScience \& Remote Sensing}, number = {1}, pages = {2111--2126}, publisher = {Taylor & Francis}, title = {{Detecting peatland vegetation patterns with multi-temporal field spectroscopy}}, url = {https://doi.org/10.1080/15481603.2022.2152303}, volume = {59}, year = {2022} } @article{Patzner2022, annote = {doi: 10.1021/acs.est.1c06937}, author = {Patzner, Monique S and Kainz, Nora and Lundin, Erik and Barczok, Maximilian and Smith, Chelsea and Herndon, Elizabeth and Kinsman-Costello, Lauren and Fischer, Stefan and Straub, Daniel and Kleindienst, Sara and Kappler, Andreas and Bryce, Casey}, doi = {10.1021/acs.est.1c06937}, issn = {0013-936X}, journal = {Environmental Science & Technology}, month = {apr}, number = {7}, pages = {4620--4631}, publisher = {American Chemical Society}, title = {{Seasonal Fluctuations in Iron Cycling in Thawing Permafrost Peatlands}}, url = {https://doi.org/10.1021/acs.est.1c06937}, volume = {56}, year = {2022} } @article{Paz2021, author = {Paz, La and City, Iloilo and Oducado, Ryan Michael F and Visayas, Assistant West and Paz, La and City, Iloilo}, file = {:Users/villekasurinen/Downloads/SSRN-id4231104.pdf:pdf}, keywords = {covid-19,e-learning,education,nursing,online learning,students}, number = {2}, pages = {1170--1177}, title = {{ot Pr ep rin pe er re vie we Pr ep rin t n ot pe er re vie we}}, volume = {14}, year = {2021} } @article{https://doi.org/10.1111/gcb.16534, abstract = {Abstract Boreal forests are important global carbon (C) sinks and, therefore, considered as a key element in climate change mitigation policies. However, their actual C sink strength is uncertain and under debate, particularly for the actively managed forests in the boreal regions of Fennoscandia. In this study, we use an extensive set of biometric- and chamber-based C flux data collected in 50 forest stands (ranging from 5 to 211 years) over 3 years (2016–2018) with the aim to explore the variations of the annual net ecosystem production (NEP; i.e., the ecosystem C balance) across a 68 km2 managed boreal forest landscape in northern Sweden. Our results demonstrate that net primary production rather than heterotrophic respiration regulated the spatio-temporal variations of NEP across the heterogeneous mosaic of the managed boreal forest landscape. We further find divergent successional patterns of NEP in our managed forests relative to naturally regenerating boreal forests, including (i) a fast recovery of the C sink function within the first decade after harvest due to the rapid establishment of a productive understory layer and (ii) a sustained C sink in old stands (131–211 years). We estimate that the rotation period for optimum C sequestration extends to 138 years, which over multiple rotations results in a long-term C sequestration rate of 86.5 t C ha−1 per rotation. Our study highlights the potential of forest management to maximize C sequestration of boreal forest landscapes and associate climate change mitigation effects by developing strategies that optimize tree biomass production rather than heterotrophic soil C emissions.}, author = {Peichl, Matthias and Mart{\'{i}}nez-Garc{\'{i}}a, Eduardo and Fransson, Johan E S and Wallerman, J{\"{o}}rgen and Laudon, Hjalmar and Lundmark, Tomas and Nilsson, Mats B}, doi = {https://doi.org/10.1111/gcb.16534}, journal = {Global Change Biology}, keywords = { carbon sequestration, climate change mitigation, forest management, heterotrophic respiration, net primary production, rotation-forestry,boreal forest landscape}, number = {n/a}, title = {{Landscape-variability of the carbon balance across managed boreal forests}}, url = {https://onlinelibrary.wiley.com/doi/abs/10.1111/gcb.16534}, volume = {n/a} } @article{https://doi.org/10.1002/qj.4386, abstract = {Stably stratified roughness sublayer flows are ubiquitous yet remain difficult to represent in models and to interpret using field experiments. Here, continuous high-frequency potential temperature profiles from the forest floor up to 6.5 times the canopy height observed with distributed temperature sensing (DTS) are used to link eddy topology to roughness sublayer stability correction functions and coupling between air layers within and above the canopy. The experiments are conducted at two forest stands classified as hydrodynamically sparse and dense. Near-continuous profiles of eddy sizes (length scales) and effective mixing lengths for heat are derived from the observed profiles using a novel conditional sampling approach. The approach utilizes potential temperature isoline fluctuations from a statically stable background state. The transport of potential temperature by an observed eddy is assumed to be conserved (adiabatic movement) and we assume that irreversible heat exchange between the eddy and the surrounding background occurs along the (vertical) periphery of the eddy. This assumption is analogous to Prandtl's mixing-length concept, where momentum is transported rapidly vertically and then equilibrated with the local mean velocity gradient. A distinct dependence of the derived length scales on background stratification, height above ground, and canopy characteristics emerges from the observed profiles. Implications of these findings for (1) the failure of Monin–Obukhov similarity in the roughness sublayer and (2) above-canopy flow coupling to the forest floor are examined. The findings have practical applications in terms of analysing similar DTS data sets with the proposed approach, modelling roughness sublayer flows, and interpreting nocturnal eddy covariance measurements above tall forested canopies.}, author = {Peltola, Olli and Aurela, Mika and Launiainen, Samuli and Katul, Gabriel}, doi = {https://doi.org/10.1002/qj.4386}, journal = {Quarterly Journal of the Royal Meteorological Society}, keywords = { DTS, length scale, mixing length, roughness sublayer, stable stratification, turbulence,canopy}, number = {749}, pages = {3756--3773}, title = {{Probing eddy size and its effective mixing length in stably stratified roughness sublayer flows}}, url = {https://rmets.onlinelibrary.wiley.com/doi/abs/10.1002/qj.4386}, volume = {148}, year = {2022} } @article{Peng2022, abstract = {Atmospheric methane growth reached an exceptionally high rate of 15.1 ± 0.4 parts per billion per year in 2020 despite a probable decrease in anthropogenic methane emissions during COVID-19 lockdowns1. Here we quantify changes in methane sources and in its atmospheric sink in 2020 compared with 2019. We find that, globally, total anthropogenic emissions decreased by 1.2 ± 0.1 teragrams of methane per year (Tg CH4 yr−1), fire emissions decreased by 6.5 ± 0.1 Tg CH4 yr−1 and wetland emissions increased by 6.0 ± 2.3 Tg CH4 yr−1. Tropospheric OH concentration decreased by 1.6 ± 0.2 per cent relative to 2019, mainly as a result of lower anthropogenic nitrogen oxide (NOx) emissions and associated lower free tropospheric ozone during pandemic lockdowns2. From atmospheric inversions, we also infer that global net emissions increased by 6.9 ± 2.1 Tg CH4 yr−1 in 2020 relative to 2019, and global methane removal from reaction with OH decreased by 7.5 ± 0.8 Tg CH4 yr−1. Therefore, we attribute the methane growth rate anomaly in 2020 relative to 2019 to lower OH sink (53 ± 10 per cent) and higher natural emissions (47 ± 16 per cent), mostly from wetlands. In line with previous findings3,4, our results imply that wetland methane emissions are sensitive to a warmer and wetter climate and could act as a positive feedback mechanism in the future. Our study also suggests that nitrogen oxide emission trends need to be taken into account when implementing the global anthropogenic methane emissions reduction pledge5.}, author = {Peng, Shushi and Lin, Xin and Thompson, Rona L and Xi, Yi and Liu, Gang and Hauglustaine, Didier and Lan, Xin and Poulter, Benjamin and Ramonet, Michel and Saunois, Marielle and Yin, Yi and Zhang, Zhen and Zheng, Bo and Ciais, Philippe}, doi = {10.1038/s41586-022-05447-w}, issn = {1476-4687}, journal = {Nature}, number = {7940}, pages = {477--482}, title = {{Wetland emission and atmospheric sink changes explain methane growth in 2020}}, url = {https://doi.org/10.1038/s41586-022-05447-w}, volume = {612}, year = {2022} } @article{egusphere-2022-952, author = {Petersen, R C and Holst, T and M{\"{o}}lder, M and Kljun, N and Rinne, J}, doi = {10.5194/egusphere-2022-952}, journal = {EGUsphere}, pages = {1--30}, title = {{Vertical distribution of sources and sinks of VOCs within a boreal forest canopy}}, url = {https://egusphere.copernicus.org/preprints/egusphere-2022-952/}, volume = {2022}, year = {2022} } @article{acp-2022-560, author = {{Petersson Sj{\"{o}}gren}, M and Alsved, M and {\v{S}}antl-Temkiv, T and {Bjerring Kristensen}, T and L{\"{o}}ndahl, J}, doi = {10.5194/acp-2022-560}, journal = {Atmospheric Chemistry and Physics Discussions}, pages = {1--26}, title = {{Measurement report: Atmospheric fluorescent bioaerosol concentrations measured during 18 months in a coniferous forest in the south of Sweden}}, url = {https://acp.copernicus.org/preprints/acp-2022-560/}, volume = {2022}, year = {2022} } @article{doi:10.1126/sciadv.abl9250, abstract = {It is not currently possible to quantify regional-scale fossil fuel carbon dioxide (ffCO2) emissions with high accuracy in near real time. Existing atmospheric methods for separating ffCO2 from large natural carbon dioxide variations are constrained by sampling limitations, so that estimates of regional changes in ffCO2 emissions, such as those occurring in response to coronavirus disease 2019 (COVID-19) lockdowns, rely on indirect activity data. We present a method for quantifying regional signals of ffCO2 based on continuous atmospheric measurements of oxygen and carbon dioxide combined into the tracer “atmospheric potential oxygen” (APO). We detect and quantify ffCO2 reductions during 2020–2021 caused by the two U.K. COVID-19 lockdowns individually using APO data from Weybourne Atmospheric Observatory in the United Kingdom and a machine learning algorithm. Our APO-based assessment has near–real-time potential and provides high-frequency information that is in good agreement with the spread of ffCO2 emissions reductions from three independent lower-frequency U.K. estimates. “Atmospheric potential oxygen” is used to quantify fossil fuel CO2 reductions from COVID-19 U.K. lockdowns in 2020–2021.}, author = {Pickers, Penelope A and Manning, Andrew C and Qu{\'{e}}r{\'{e}}, Corinne Le and Forster, Grant L and Luijkx, Ingrid T and Gerbig, Christoph and Fleming, Leigh S and Sturges, William T}, doi = {10.1126/sciadv.abl9250}, journal = {Science Advances}, number = {16}, pages = {eabl9250}, title = {{Novel quantification of regional fossil fuel CO2 reductions during COVID-19 lockdowns using atmospheric oxygen measurements}}, url = {https://www.science.org/doi/abs/10.1126/sciadv.abl9250}, volume = {8}, year = {2022} } @article{acp-22-10721-2022, author = {Pieber, S M and Tuzson, B and Henne, S and Karstens, U and Gerbig, C and Koch, F.-T. and Brunner, D and Steinbacher, M and Emmenegger, L}, doi = {10.5194/acp-22-10721-2022}, journal = {Atmospheric Chemistry and Physics}, number = {16}, pages = {10721--10749}, title = {{Analysis of regional CO$_{2}$ contributions at the high Alpine observatory Jungfraujoch by means of atmospheric transport simulations and $\delta^{13}$C}}, url = {https://acp.copernicus.org/articles/22/10721/2022/}, volume = {22}, year = {2022} } @article{s22093251, abstract = {High spatial resolution and geolocation accuracy canopy evapotranspiration (ET) maps are well suited tools for evaluation of small plot field trials. While creating such a map by use of an energy balance model is routinely performed, the acquisition of the necessary imagery at a suitable quality is still challenging. An UAV based thermal/RGB integrated imaging system was built using the RaspberryPi (RPi) microcomputer as a central unit. The imagery served as input to the two-source energy balance model pyTSEB to derive the ET map. The setup’s flexibility and modularity are based on the multiple interfaces provided by the RPi and the software development kit (SDK) provided for the thermal camera. The SDK was installed on the RPi and used to trigger cameras, retrieve and store images and geolocation information from an onboard GNSS rover for PPK processing. The system allows acquisition of 8 cm spatial resolution thermal imagery from a 60 m height of flight and less than 7 cm geolocation accuracy of the mosaicked RGB imagery. Modelled latent heat flux data have been validated against latent heat fluxes measured by eddy covariance stations at two locations with RMSE of 75 W/m2 over a two-year study period.}, author = {Pint{\'{e}}r, Krisztina and Nagy, Zolt{\'{a}}n}, doi = {10.3390/s22093251}, issn = {1424-8220}, journal = {Sensors}, number = {9}, title = {{Building a UAV Based System to Acquire High Spatial Resolution Thermal Imagery for Energy Balance Modelling}}, url = {https://www.mdpi.com/1424-8220/22/9/3251}, volume = {22}, year = {2022} } @article{acp-22-3321-2022, author = {Platt, S M and Hov, {\O} and Berg, T and Breivik, K and Eckhardt, S and Eleftheriadis, K and Evangeliou, N and Fiebig, M and Fisher, R and Hansen, G and Hansson, H.-C. and Heintzenberg, J and Hermansen, O and Heslin-Rees, D and Holm{\'{e}}n, K and Hudson, S and Kallenborn, R and Krejci, R and Krognes, T and Larssen, S and Lowry, D and {Lund Myhre}, C and Lunder, C and Nisbet, E and Nizzetto, P B and Park, K.-T. and Pedersen, C A and {Aspmo Pfaffhuber}, K and R{\"{o}}ckmann, T and Schmidbauer, N and Solberg, S and Stohl, A and Str{\"{o}}m, J and Svendby, T and Tunved, P and T{\o}rnkvist, K and van der Veen, C and Vratolis, S and Yoon, Y J and Yttri, K E and Zieger, P and Aas, W and T{\o}rseth, K}, doi = {10.5194/acp-22-3321-2022}, journal = {Atmospheric Chemistry and Physics}, number = {5}, pages = {3321--3369}, title = {{Atmospheric composition in the European Arctic and 30$\sim$years of the Zeppelin Observatory, Ny-{\AA}lesund}}, url = {https://acp.copernicus.org/articles/22/3321/2022/}, volume = {22}, year = {2022} } @article{Pluntke2023, abstract = {Water budgets and climate are related in many ways and at all scales. Therefore, we expect climate change to trigger changes in all water budget components at any scale. For Central Europe observed and projected climate change indicates higher variability of precipitation, while evapotranspiration (ET) should increase due to higher temperatures, yielding lower and more variable infiltration and runoff. However, evidence in ET records is limited, as long-term measurements of ET are methodologically challenging and as factors other than climate are changing in parallel, like vegetation and land use. In this study, we take advantage of long-term hydro-meteorological data from the small research catchment Wernersbach (4.6 km2, dominated by Norway spruce) in operation since 1967 and from two eddy-covariance (EC) flux towers, all located in the Tharandt Forest, Germany. The tower DE-Tha is located a few kilometres east of the catchment, is spruce dominated and in operation since 1996. After a wind break of a spruce stand (situated inside the catchment) and planting of deciduous oaks, the tower DE-Hzd was set up in 2009. For the first time, we report systematically about observation, correction methods and metadata of the long data series of the observatory, represented by the Wernersbach catchment and the EC flux towers. Climate change signals in the region are mirrored in the Tharandt Forest records. They show rising air temperature with a breakpoint around 1988 and complex changes in solar radiation associated to a regional peak in air pollution around the same time. The catchment and both towers did not show any systematic differences in climate or meteorological data, allowing us to address observed changes in the water budget components as related to (i) climate change, (ii) change in vegetation, and (iii) different responses due to different soil and hydrogeological characteristics as well as methodological aspects. The catchment term ET plus storage, derived from precipitation minus runoff, showed the expected high variability with a significant increase over the more than 50 years of operation. The flux-tower DE-Tha showed much lower inter-annual variability in ET with an average annual total of 486 mm (1997 to 2019), but no significant trend. For the same period, average catchment ET was 734 mm/yr. The younger flux-tower DE-Hzd showed ET values in between, closer to catchment ET at the very dry end of the ten-year record (2010 to 2019). An analysis of decadal trends in a Budyko framework at catchment level revealed the dominating response of ET to land use or vegetation change until around 1990. The climate induced change of ET increased in the last decades, on the one hand directly due to an increased atmospheric demand. On the other hand, extreme weather events exerted harmful effects on vegetation, especially triggered by two dry years at the end of the record. Furthermore, we found that the mean annual tower ET was about 250 mm lower than catchment ET despite the careful correction for energy balance closure. We attribute this difference to soil and to a lesser extend to vegetation characteristics, but also to methodological uncertainties. There is evidence from interception and transpiration measurements at the flux tower as well as from water budget modelling that a major contribution of this difference is related to an insufficient EC closure correction during interception events. A careful consideration of rain events and evaporation from interception is recommended when addressing ET of similar evergreen forests in a humid climate, as EC records might be generally too low. This illustrates the necessity of redundant and complementary measurements when dealing with large system complexity.}, author = {Pluntke, T and Bernhofer, C and Gr{\"{u}}nwald, T and Renner, M and Prasse, H}, doi = {https://doi.org/10.1016/j.jhydrol.2022.128873}, issn = {0022-1694}, journal = {Journal of Hydrology}, keywords = {Catchment water budget,Climate change,Eddy-covariance,Forest evapotranspiration,ICOS,Land surface change}, pages = {128873}, title = {{Long-term climatological and ecohydrological analysis of a paired catchment – flux tower observatory near Dresden (Germany). Is there evidence of climate change in local evapotranspiration?}}, url = {https://www.sciencedirect.com/science/article/pii/S0022169422014433}, volume = {617}, year = {2023} } @article{Poorter2022, abstract = {Summary Generalised dose?response curves are essential to understand how plants acclimate to atmospheric CO2. We carried out a meta-analysis of 630 experiments in which C3 plants were experimentally grown at different [CO2] under relatively benign conditions, and derived dose?response curves for 85 phenotypic traits. These curves were characterised by form, plasticity, consistency and reliability. Considered over a range of 200?1200 µmol mol?1 CO2, some traits more than doubled (e.g. area-based photosynthesis; intrinsic water-use efficiency), whereas others more than halved (area-based transpiration). At current atmospheric [CO2], 64% of the total stimulation in biomass over the 200?1200 µmol mol?1 range has already been realised. We also mapped the trait responses of plants to [CO2] against those we have quantified before for light intensity. For most traits, CO2 and light responses were of similar direction. However, some traits (such as reproductive effort) only responded to light, others (such as plant height) only to [CO2], and some traits (such as area-based transpiration) responded in opposite directions. This synthesis provides a comprehensive picture of plant responses to [CO2] at different integration levels and offers the quantitative dose?response curves that can be used to improve global change simulation models.}, annote = {https://doi.org/10.1111/nph.17802}, author = {Poorter, Hendrik and Knopf, Oliver and Wright, Ian J and Temme, Andries A and Hogewoning, Sander W and Graf, Alexander and Cernusak, Lucas A and Pons, Thijs L}, doi = {https://doi.org/10.1111/nph.17802}, issn = {0028-646X}, journal = {New Phytologist}, keywords = {acclimation,dose–response curve,global change,light intensity,meta-analysis,plasticity,reaction norm}, month = {feb}, number = {4}, pages = {1560--1596}, publisher = {John Wiley & Sons, Ltd}, title = {{A meta-analysis of responses of C3 plants to atmospheric CO2: dose–response curves for 85 traits ranging from the molecular to the whole-plant level}}, url = {https://doi.org/10.1111/nph.17802}, volume = {233}, year = {2022} } @article{Reitz2022, abstract = {Flux measurements over heterogeneous surfaces with growing vegetation and a limited fetch are a difficult task, as measurement heights that are too high or too low above the canopy adversely affect results. The aim of this study is to assess implications from measurement height in regard to low-pass filtering, footprint representativeness, and energy balance closure for a clear-cut site with regrowing vegetation of varying height. For this, measurements from two open-path eddy-covariance systems at different heights are compared over the course of one growing season. Particular attention is paid to low-pass-filtering corrections, for which five different methods are compared. Results indicate significant differences between fluxes from the upper and lower systems, which likely result from footprint differences and an insufficient spectral correction for the lower system. Different low-pass-filtering corrections add an uncertainty of 3.4% (7.0%) to CO2 fluxes and 1.4% (3.0%) to H2O fluxes for the upper (lower) system, also leading to considerable differences in cumulative fluxes. Despite limitations in the analysis, which include the difficulty of applying a footprint model at this study site and the likely influence of advection on the total exchange, the analysis confirms that information about the choice of spectral correction method and measurement-height changes are critical for interpreting data at complex sites.}, author = {Reitz, Oliver and Graf, Alexander and Schmidt, Marius and Ketzler, Gunnar and Leuchner, Michael}, doi = {10.1007/s10546-022-00700-1}, issn = {1573-1472}, journal = {Boundary-Layer Meteorology}, number = {2}, pages = {277--299}, title = {{Effects of Measurement Height and Low-Pass-Filtering Corrections on Eddy-Covariance Flux Measurements Over a Forest Clearing with Complex Vegetation}}, url = {https://doi.org/10.1007/s10546-022-00700-1}, volume = {184}, year = {2022} } @article{amt-14-153-2021, author = {Reuter, M and Bovensmann, H and Buchwitz, M and Borchardt, J and Krautwurst, S and Gerilowski, K and Lindauer, M and Kubistin, D and Burrows, J P}, doi = {10.5194/amt-14-153-2021}, journal = {Atmospheric Measurement Techniques}, number = {1}, pages = {153--172}, title = {{Development of a small unmanned aircraft system to derive \chem{CO_2} emissions of anthropogenic point sources}}, url = {https://amt.copernicus.org/articles/14/153/2021/}, volume = {14}, year = {2021} } @article{rs14163912, abstract = {Current endeavors to enhance the accuracy of in situ above-ground biomass (AGB) prediction for croplands rely on close-range monitoring surveys that use unstaffed aerial vehicles (UAVs) and mounted sensors. In precision agriculture, light detection and ranging (LiDAR) technologies are currently used to monitor crop growth, plant phenotyping, and biomass dynamics at the ecosystem scale. In this study, we utilized a UAV–LiDAR sensor to monitor two crop fields and a set of machine learning (ML) methods to predict real-time AGB over two consecutive years in the region of Mid-Jutland, Denmark. During each crop growing period, UAV surveys were conducted in parallel with AGB destructive sampling every 7–15 days, the AGB samples from which were used as the ground truth data. We evaluated the ability of the ML models to estimate the real-time values of AGB at a sub-meter resolution (0.17–0.52 m2). An extremely randomized trees (ERT) regressor was selected for the regression analysis, based on its predictive performance for the first year’s growing season. The model was retrained using previously identified hyperparameters to predict the AGB of the crops in the second year. The ERT performed AGB estimation using height and reflectance metrics from LiDAR-derived point cloud data and achieved a prediction performance of R2 = 0.48 at a spatial resolution of 0.35 m2. The prediction performance could be improved significantly by aggregating adjacent predictions (R2 = 0.71 and R2 = 0.93 at spatial resolutions of 1 m2 and 2 m2, respectively) as they ultimately converged to the reference biomass values because any individual errors averaged out. The AGB prediction results were examined as function of predictor type, training set size, sampling resolution, phenology, and canopy density. The results demonstrated that when combined with ML regression methods, the UAV–LiDAR method could be used to provide accurate real-time AGB prediction for crop fields at a high resolution, thereby providing a way to map their biochemical constituents.}, author = {Revenga, Jaime C and Trepekli, Katerina and Oehmcke, Stefan and Jensen, Rasmus and Li, Lei and Igel, Christian and Gieseke, Fabian Cristian and Friborg, Thomas}, doi = {10.3390/rs14163912}, issn = {2072-4292}, journal = {Remote Sensing}, number = {16}, title = {{Above-Ground Biomass Prediction for Croplands at a Sub-Meter Resolution Using UAV–LiDAR and Machine Learning Methods}}, url = {https://www.mdpi.com/2072-4292/14/16/3912}, volume = {14}, year = {2022} } @article{s22197410, abstract = {Methane (CH4), a powerful greenhouse gas (GHG), has been identified as a key target for emission reduction in the Paris agreement, but it is not currently clear where efforts should be focused to make the greatest impact. Currently, activity data and standard emission factors (EF) are used to generate GHG emission inventories. Many of the EFs are globally uniform and do not account for regional variability in industrial or agricultural practices and/or regulation. Regional EFs can be derived from top–down emissions measurements and used to make bespoke regional GHG emission inventories that account for geopolitical and social variability. However, most large-scale top–down approaches campaigns require significant investment. To address this, lower-cost driving surveys (DS) have been identified as a viable alternative to more established methods. DSs can take top–down measurements of many emission sources in a relatively short period of time, albeit with a higher uncertainty. To investigate the use of a portable measurement system, a 2260 km DS was conducted throughout the Denver–Julesburg Basin (DJB). The DJB covers an area of 8000 km2 north of Denver, CO and is densely populated with CH4 emission sources, including oil and gas (O and G) operations, agricultural operations (AGOs), lakes and reservoirs. During the DS, 157 individual CH4 emission sources were detected; 51%, 43% and 4% of sources were AGOs, O and G operations, and natural sources, respectively. Methane emissions from each source were quantified using downwind concentration and meteorological data and AGOs and O and G operations represented nearly all the CH4 emissions in the DJB, accounting for 54% and 37% of the total emission, respectively. Operations with similar emission sources were grouped together and average facility emission estimates were generated. For agricultural sources, emissions from feedlot cattle, dairy cows and sheep were estimated at 5, 31 and 1 g CH4 head−1 h−1, all of which agreed with published values taken from focused measurement campaigns. Similarly, for O and G average emissions for well pads, compressor stations and gas processing plants (0.5, 14 and 110 kg CH4 facility−1 h−1) were in reasonable agreement with emission estimates from intensive measurement campaigns. A comparison of our basin wide O and G emissions to measurements taken a decade ago show a decrease of a factor of three, which can feasibly be explained by changes to O and G regulation over the past 10 years, while emissions from AGOs have remained constant over the same time period. Our data suggest that DSs could be a low-cost alternative to traditional measurement campaigns and used to screen many emission sources within a region to derive representative regionally specific and time-sensitive EFs. The key benefit of the DS is that many regions can be screened and emission reduction targets identified where regional EFs are noticeably larger than the regional, national or global averages.}, author = {Riddick, Stuart N and Cheptonui, Fancy and Yuan, Kexin and Mbua, Mercy and Day, Rachel and Vaughn, Timothy L and Duggan, Aidan and Bennett, Kristine E and Zimmerle, Daniel J}, doi = {10.3390/s22197410}, issn = {1424-8220}, journal = {Sensors}, number = {19}, title = {{Estimating Regional Methane Emission Factors from Energy and Agricultural Sector Sources Using a Portable Measurement System: Case Study of the Denver–Julesburg Basin}}, url = {https://www.mdpi.com/1424-8220/22/19/7410}, volume = {22}, year = {2022} } @article{ROCHA2022104051, abstract = {As impervious surfaces have seized most areas in cities worldwide, urban heat island (UHI) has become a global concern. Urban green infrastructures (UGI) are crucial to providing microclimate regulation and thermal comfort through evapotranspiration (ET) and shading. High-spatiotemporal-resolution ET maps are required to plan and manage UGI to mitigate the UHI and droughts. We propose a method using open-access data, including hourly meteorological data and remote sensing vegetation parameters, to predict heat fluxes using a soil-vegetation-atmosphere model. The ET prediction accuracy was assessed using eddy covariance towers, showing an R2 of 0.84 for the residential-vegetated site and 0.57 for the built-up site during 2019. A greening cooling service index (GCoS), divided into evapotranspirative (ECoS) and radiative (RCoS) cooling effects were mapped for Berlin, Germany. Almost half of the population and 21% of the city area are located in low GCoS (<0.25). Based upon climate change scenarios, a rise in temperature increases the annual ET, while plant stress and droughts considerably decrease overall cooling services. Simulation of climatological scenarios and plant traits can help to define more suitable species adapted for urban environments. The presented method provides an effective decision-making tool for urban planning to reduce heat risk for urban residents.}, author = {Rocha, Alby Duarte and Vulova, Stenka and Meier, Fred and F{\"{o}}rster, Michael and Kleinschmit, Birgit}, doi = {https://doi.org/10.1016/j.scs.2022.104051}, issn = {2210-6707}, journal = {Sustainable Cities and Society}, keywords = { Ecosystem services, Nature-based solutions (NBS), SCOPE model, Sustainable cities, Urban green infrastructure (UGI), Urban heat island (UHI),Evapotranspiration (ET)}, pages = {104051}, title = {{Mapping evapotranspirative and radiative cooling services in an urban environment}}, url = {https://www.sciencedirect.com/science/article/pii/S2210670722003699}, volume = {85}, year = {2022} } @article{acp-22-2447-2022, author = {Rust, D and Katharopoulos, I and Vollmer, M K and Henne, S and O'Doherty, S and Say, D and Emmenegger, L and Zenobi, R and Reimann, S}, doi = {10.5194/acp-22-2447-2022}, journal = {Atmospheric Chemistry and Physics}, number = {4}, pages = {2447--2466}, title = {{Swiss halocarbon emissions for 2019 to 2020 assessed from regional atmospheric observations}}, url = {https://acp.copernicus.org/articles/22/2447/2022/}, volume = {22}, year = {2022} } @article{gmd-15-2813-2022, author = {Salmon, E and J{\'{e}}gou, F and Guenet, B and Jourdain, L and Qiu, C and Bastrikov, V and Guimbaud, C and Zhu, D and Ciais, P and Peylin, P and Gogo, S and Laggoun-D{\'{e}}farge, F and Aurela, M and Bret-Harte, M S and Chen, J and Chojnicki, B H and Chu, H and Edgar, C W and Euskirchen, E S and Flanagan, L B and Fortuniak, K and Holl, D and Klatt, J and Kolle, O and Kowalska, N and Kutzbach, L and Lohila, A and Merbold, L and Pawlak, W and Sachs, T and Ziembli{\'{n}}ska, K}, doi = {10.5194/gmd-15-2813-2022}, journal = {Geoscientific Model Development}, number = {7}, pages = {2813--2838}, title = {{Assessing methane emissions for northern peatlands in ORCHIDEE-PEAT revision 7020}}, url = {https://gmd.copernicus.org/articles/15/2813/2022/}, volume = {15}, year = {2022} } @article{Salmon2022, abstract = {In the global methane budget, the largest natural source is attributed to wetlands, which encompass all ecosystems composed of waterlogged or inundated ground, capable of methane production. Among them, northern peatlands that store large amounts of soil organic carbon have been functioning, since the end of the last glaciation period, as long-term sources of methane (CH4) and are one of the most significant methane sources among wetlands. To reduce uncertainty of quantifying methane flux in the global methane budget, it is of significance to understand the underlying processes for methane production and fluxes in northern peatlands. A methane model that features methane production and transport by plants, ebullition process and diffusion in soil, oxidation to CO2, and CH4 fluxes to the atmosphere has been embedded in the ORCHIDEE-PEAT land surface model that includes an explicit representation of northern peatlands. ORCHIDEE-PCH4 was calibrated and evaluated on 14 peatland sites distributed on both the Eurasian and American continents in the northern boreal and temperate regions. Data assimilation approaches were employed to optimized parameters at each site and at all sites simultaneously. Results show that methanogenesis is sensitive to temperature and substrate availability over the top 75cm of soil depth. Methane emissions estimated using single site optimization (SSO) of model parameters are underestimated by 9gCH4m-2 yr-1 on average (i.e., 50% higher than the site average of yearly methane emissions). While using the multi-site optimization (MSO), methane emissions are overestimated by 5gCH4m-2 yr-1 on average across all investigated sites (i.e., 37% lower than the site average of yearly methane emissions).}, author = {Salmon, Elodie and J{\'{e}}gou, Fabrice and Guenet, Bertrand and Jourdain, Line and Qiu, Chunjing and Bastrikov, Vladislav and Guimbaud, Christophe and Zhu, Dan and Ciais, Philippe and Peylin, Philippe and Gogo, S{\'{e}}bastien and Laggoun-D{\'{e}}farge, Fatima and Aurela, Mika and Bret-Harte, M. Syndonia and Chen, Jiquan and Chojnicki, Bogdan H. and Chu, Housen and Edgar, Colin W. and Euskirchen, Eugenie S. and Flanagan, Lawrence B. and Fortuniak, Krzysztof and Holl, David and Klatt, Janina and Kolle, Olaf and Kowalska, Natalia and Kutzbach, Lars and Lohila, Annalea and Merbold, Lutz and Pawlak, W{\l}odzimierz and Sachs, Torsten and Ziembli{\'{n}}ska, Klaudia}, doi = {10.5194/gmd-15-2813-2022}, file = {:Users/villekasurinen/Downloads/gmd-2021-280.pdf:pdf}, issn = {19919603}, journal = {Geoscientific Model Development}, number = {7}, pages = {2813--2838}, title = {{Assessing methane emissions for northern peatlands in ORCHIDEE-PEAT revision 7020}}, volume = {15}, year = {2022} } @article{Salomon2022, abstract = {Heatwaves exert disproportionately strong and sometimes irreversible impacts on forest ecosystems. These impacts remain poorly understood at the tree and species level and across large spatial scales. Here, we investigate the effects of the record-breaking 2018 European heatwave on tree growth and tree water status using a collection of high-temporal resolution dendrometer data from 21 species across 53 sites. Relative to the two preceding years, annual stem growth was not consistently reduced by the 2018 heatwave but stems experienced twice the temporary shrinkage due to depletion of water reserves. Conifer species were less capable of rehydrating overnight than broadleaves across gradients of soil and atmospheric drought, suggesting less resilience toward transient stress. In particular, Norway spruce and Scots pine experienced extensive stem dehydration. Our high-resolution dendrometer network was suitable to disentangle the effects of a severe heatwave on tree growth and desiccation at large-spatial scales in situ, and provided insights on which species may be more vulnerable to climate extremes.}, author = {Salom{\'{o}}n, Roberto L and Peters, Richard L and Zweifel, Roman and Sass-Klaassen, Ute G W and Stegehuis, Annemiek I and Smiljanic, Marko and Poyatos, Rafael and Babst, Flurin and Cienciala, Emil and Fonti, Patrick and Lerink, Bas J W and Lindner, Marcus and Martinez-Vilalta, Jordi and Mencuccini, Maurizio and Nabuurs, Gert-Jan and van der Maaten, Ernst and von Arx, Georg and B{\"{a}}r, Andreas and Akhmetzyanov, Linar and Balanzategui, Daniel and Bellan, Michal and Bendix, J{\"{o}}rg and Berveiller, Daniel and Bla{\v{z}}enec, Miroslav and {\v{C}}ada, Vojt{\v{e}}ch and Carraro, Vinicio and Cecchini, S{\'{e}}bastien and Chan, Tommy and Conedera, Marco and Delpierre, Nicolas and Delzon, Sylvain and Ditmarov{\'{a}}, Ľubica and Dolezal, Jiri and Dufr{\^{e}}ne, Eric and Edvardsson, Johannes and Ehekircher, Stefan and Forner, Alicia and Frouz, Jan and Ganthaler, Andrea and Gryc, Vladim{\'{i}}r and G{\"{u}}ney, Aylin and Heinrich, Ingo and Hentschel, Rainer and Janda, Pavel and Je{\v{z}}{\'{i}}k, Marek and Kahle, Hans-Peter and Kn{\"{u}}sel, Simon and Krejza, Jan and Kuberski, {\L}ukasz and Ku{\v{c}}era, Jiř{\'{i}} and Lebourgeois, Fran{\c{c}}ois and Mikol{\'{a}}{\v{s}}, Martin and Matula, Radim and Mayr, Stefan and Oberhuber, Walter and Obojes, Nikolaus and Osborne, Bruce and Paljakka, Teemu and Plichta, Roman and Rabbel, Inken and Rathgeber, Cyrille B K and Salmon, Yann and Saunders, Matthew and Scharnweber, Tobias and Sitkov{\'{a}}, Zuzana and Stangler, Dominik Florian and Stere{\'{n}}czak, Krzysztof and Stojanovi{\'{c}}, Marko and Střelcov{\'{a}}, Katar{\'{i}}na and Sv{\v{e}}tl{\'{i}}k, Jan and Svoboda, Miroslav and Tobin, Brian and Trotsiuk, Volodymyr and Urban, Josef and Valladares, Fernando and Vavr{\v{c}}{\'{i}}k, Hanu{\v{s}} and Vejpustkov{\'{a}}, Monika and Walthert, Lorenz and Wilmking, Martin and Zin, Ewa and Zou, Junliang and Steppe, Kathy}, doi = {10.1038/s41467-021-27579-9}, issn = {2041-1723}, journal = {Nature Communications}, number = {1}, pages = {28}, title = {{The 2018 European heatwave led to stem dehydration but not to consistent growth reductions in forests}}, url = {https://doi.org/10.1038/s41467-021-27579-9}, volume = {13}, year = {2022} } @article{amt-15-4339-2022, author = {Schneider, M and Ertl, B and Tu, Q and Diekmann, C J and Khosrawi, F and R{\"{o}}hling, A N and Hase, F and Dubravica, D and Garc\'\ia, O E and Sep{\'{u}}lveda, E and Borsdorff, T and Landgraf, J and Lorente, A and Butz, A and Chen, H and Kivi, R and Laemmel, T and Ramonet, M and Crevoisier, C and Pernin, J and Steinbacher, M and Meinhardt, F and Strong, K and Wunch, D and Warneke, T and Roehl, C and Wennberg, P O and Morino, I and Iraci, L T and Shiomi, K and Deutscher, N M and Griffith, D W T and Velazco, V A and Pollard, D F}, doi = {10.5194/amt-15-4339-2022}, journal = {Atmospheric Measurement Techniques}, number = {14}, pages = {4339--4371}, title = {{Synergetic use of IASI profile and TROPOMI total-column level 2 methane retrieval products}}, url = {https://amt.copernicus.org/articles/15/4339/2022/}, volume = {15}, year = {2022} } @article{Seiler2022, abstract = {The Global Carbon Project estimates that the terrestrial biosphere has absorbed about one-third of anthropogenic CO2 emissions during the 1959–2019 period. This sink-estimate is produced by an ensemble of terrestrial biosphere models and is consistent with the land uptake inferred from the residual of emissions and ocean uptake. The purpose of our study is to understand how well terrestrial biosphere models reproduce the processes that drive the terrestrial carbon sink. One challenge is to decide what level of agreement between model output and observation-based reference data is adequate considering that reference data are prone to uncertainties. To define such a level of agreement, we compute benchmark scores that quantify the similarity between independently derived reference data sets using multiple statistical metrics. Models are considered to perform well if their model scores reach benchmark scores. Our results show that reference data can differ considerably, causing benchmark scores to be low. Model scores are often of similar magnitude as benchmark scores, implying that model performance is reasonable given how different reference data are. While model performance is encouraging, ample potential for improvements remains, including a reduction in a positive leaf area index bias, improved representations of processes that govern soil organic carbon in high latitudes, and an assessment of causes that drive the inter-model spread of gross primary productivity in boreal regions and humid tropics. The success of future model development will increasingly depend on our capacity to reduce and account for observational uncertainties.}, author = {Seiler, Christian and Melton, Joe R. and Arora, Vivek K. and Sitch, Stephen and Friedlingstein, Pierre and Anthoni, Peter and Goll, Daniel and Jain, Atul K. and Joetzjer, Emilie and Lienert, Sebastian and Lombardozzi, Danica and Luyssaert, Sebastiaan and Nabel, Julia E.M.S. and Tian, Hanqin and Vuichard, Nicolas and Walker, Anthony P. and Yuan, Wenping and Zaehle, S{\"{o}}nke}, doi = {10.1029/2021MS002946}, file = {:Users/villekasurinen/Downloads/J Adv Model Earth Syst - 2022 - Seiler - Are Terrestrial Biosphere Models Fit for Simulating the Global Land Carbon Sink.pdf:pdf}, issn = {19422466}, journal = {Journal of Advances in Modeling Earth Systems}, keywords = {biogeochemical cycles, processes, and modeling,biosphere/atmosphere interactions,carbon cycling}, number = {5}, title = {{Are Terrestrial Biosphere Models Fit for Simulating the Global Land Carbon Sink?}}, volume = {14}, year = {2022} } @article{Serk2022, annote = {doi: 10.1021/acs.est.2c03513}, author = {Serk, Henrik and Nilsson, Mats B and Figueira, Jo{\~{a}}o and Kr{\"{u}}ger, Jan Paul and Leifeld, Jens and Alewell, Christine and Schleucher, J{\"{u}}rgen}, doi = {10.1021/acs.est.2c03513}, issn = {0013-936X}, journal = {Environmental Science & Technology}, month = {dec}, number = {23}, pages = {17410--17419}, publisher = {American Chemical Society}, title = {{Organochemical Characterization of Peat Reveals Decomposition of Specific Hemicellulose Structures as the Main Cause of Organic Matter Loss in the Acrotelm}}, url = {https://doi.org/10.1021/acs.est.2c03513}, volume = {56}, year = {2022} } @article{SHAHBAZ2022154876, abstract = {Boreal forests have a large impact on the global greenhouse gas balance and their soils constitute an important carbon (C) reservoir. Mature boreal forests are typically a net CO2 sink, but there are also examples of boreal forests that are persistent CO2 sources. The reasons remain often unknown, presumably due to a lack of understanding of how biotic and abiotic drivers interact to determine the microbial respiration of soil organic matter (SOM). This study aimed at identifying the main drivers of microbial SOM respiration and CO2 and CH4 soil chamber-fluxes within dry and wet sampling areas at the mature boreal forest of Norunda, Sweden, a persistent net CO2 source. The spatial heterogeneity of the drivers was assessed with a geostatistical approach combined with stepwise multiple regression. We found that heterotrophic soil respiration increased with SOM content and nitrogen (N) availability, while the SOM reactivity, i.e., SOM specific respiration, was determined by soil moisture and N availability. The latter suggests that microbial activity was N rather than C limited and that microbial N mining might be driving old-SOM decomposition, which was observed through a positive correlation between soil respiration and its $\delta$13C values. SOM specific heterotrophic respiration was lower in wet than in dry areas, while no such dependencies were found for chamber-based soil CO2 fluxes, implying that oxygen depletion resulted in lower SOM reactivity. The chamber-based soil CH4 flux differed significantly between the wet and dry areas. In the wet area, we observed net CH4 emission that was positively related to soil moisture and NH4+-N content. Taken together, our findings suggest that N availability has a strong regulatory effect on soil CO2 and CH4 emissions at Norunda, and that microbial decomposition of old-SOM to release bioavailable N might be partly responsible for the net CO2 emission at the site.}, author = {Shahbaz, Muhammad and Bengtson, Per and Mertes, Jordan R and Kulessa, Bernd and Kljun, Natascha}, doi = {https://doi.org/10.1016/j.scitotenv.2022.154876}, issn = {0048-9697}, journal = {Science of The Total Environment}, keywords = { Geostatistics, Microbial respiration, Nutrients, Soil organic matter, Spatial heterogeneity,Carbon dioxide and methane flux}, pages = {154876}, title = {{Spatial heterogeneity of soil carbon exchanges and their drivers in a boreal forest}}, url = {https://www.sciencedirect.com/science/article/pii/S0048969722019696}, volume = {831}, year = {2022} } @article{Shapkalijevski2020, author = {Shapkalijevski, Metodija M and Viana, Samuel and Boone, Aaron and Rodier, Quentin and Moigne, Patrick Le}, file = {:Users/villekasurinen/Downloads/ACCORD-NL2_Viana.pdf:pdf}, number = {Harman 2012}, pages = {82--90}, title = {{Introducing a roughness-sublayer in the vegetation-atmosphere coupling of HARMONIE-AROME}}, year = {2020} } @article{SHEKHAR2022113282, abstract = {The collection of various long-term reconstructed solar-induced fluorescence (SIF) datasets derived at a range of spatio-temporal scales provides new opportunities for modelling vegetation dynamics, in particular, gross primary productivity (GPP). Information about the proximity of the reconstructed SIF (SIFr) datasets to GPP across land cover types and climatic conditions provides important support for a better application of these products for modelling applications. We conducted a multiscale analysis of four different long-term (12 years, 2007–2018) high-resolution global SIFr datasets (0.05° × 0.05°), namely – CSIF (Contiguous SIF), GOSIF (Global OCO-2 SIF), LUE-SIF (Light Use Efficiency SIF), and HSIF (Harmonized SIF) - at 4-day, 8-day, and monthly time scales and found that for the majority of sites, the SIFr is linearly related to ground-based GPP measurements with the eddy covariance method. While the relationship between SIFr and GPP (i.e., the slope - GPP/SIFr) varied significantly across the SIFr datasets, sites, and land cover types, all four SIFr datasets were unequivocally a better predictor of GPP compared to remotely sensed vegetation indices – NDVI (normalized difference vegetation index) and EVI (enhanced vegetation index), sensed by the MODIS satellite. Furthermore, we also analyzed SIF-GPP relationships during drought vs non-drought conditions and found that for about 30% of the sites, comprising mostly non-forests site, the SIF-GPP relationship became weaker (decreased R2) with a lower slope during drought conditions compared to non-drought conditions. Among the four different products, the CSIF (at 4-day timescale) and GOSIF (at 8-day timescale) predicted GPP better compared to LUE-SIF and HSIF across all land cover types. Owing to their long-term availability (since 2000 for CSIF and GOSIF), these SIFr datasets combined with proxies of ecosystem properties can be used to appropriately capture vegetation dynamics and the interannual variabilities across a wide range of climatic conditions.}, author = {Shekhar, Ankit and Buchmann, Nina and Gharun, Mana}, doi = {https://doi.org/10.1016/j.rse.2022.113282}, issn = {0034-4257}, journal = {Remote Sensing of Environment}, keywords = { Eddy-covariance, GOME-2, GOSIF, HSIF, MODIS, OCO-2,CSIF}, pages = {113282}, title = {{How well do recently reconstructed solar-induced fluorescence datasets model gross primary productivity?}}, url = {https://www.sciencedirect.com/science/article/pii/S0034425722003881}, volume = {283}, year = {2022} } @article{gmd-15-3603-2022, author = {Smith, N D and Burke, E J and {Schanke Aas}, K and Althuizen, I H J and Boike, J and Christiansen, C T and Etzelm{\"{u}}ller, B and Friborg, T and Lee, H and Rumbold, H and Turton, R H and Westermann, S and Chadburn, S E}, doi = {10.5194/gmd-15-3603-2022}, journal = {Geoscientific Model Development}, number = {9}, pages = {3603--3639}, title = {{Explicitly modelling microtopography in permafrost landscapes in a land surface model (JULES vn5.4\_microtopography)}}, url = {https://gmd.copernicus.org/articles/15/3603/2022/}, volume = {15}, year = {2022} } @article{Smith2022, abstract = {Microtopography can be a key driver of heterogeneity in the ground thermal and hydrological regime of permafrost landscapes. In turn, this heterogeneity can influence plant communities, methane fluxes, and the initiation of abrupt thaw processes. Here we have implemented a two-tile representation of microtopography in JULES (the Joint UK Land Environment Simulator), where tiles are representative of repeating patterns of elevation difference. Tiles are coupled by lateral flows of water, heat, and redistribution of snow, and a surface water store is added to represent ponding. Simulations are performed of two Siberian polygon sites, (Samoylov and Kytalyk) and two Scandinavian palsa sites (Stordalen and I{\v{s}}koras). The model represents the observed differences between greater snow depth in hollows vs. raised areas well. The model also improves soil moisture for hollows vs. the non-tiled configuration ("standard JULES") though the raised tile remains drier than observed. The modelled differences in snow depths and soil moisture between tiles result in the lower tile soil temperatures being warmer for palsa sites, as in reality. However, when comparing the soil temperatures for July at 20ĝ€¯cm depth, the difference in temperature between tiles, or "temperature splitting", is smaller than observed (3.2 vs. 5.5ĝ€¯ĝ C). Polygons display small (0.2ĝ€¯ĝ C) to zero temperature splitting, in agreement with observations. Consequently, methane fluxes are near identical (+0ĝ€¯% to 9ĝ€¯%) to those for standard JULES for polygons, although they can be greater than standard JULES for palsa sites (+10ĝ€¯% to 49ĝ€¯%). Through a sensitivity analysis we quantify the relative importance of model processes with respect to soil moisture and temperatures, identifying which parameters result in the greatest uncertainty in modelled temperature. Varying the palsa elevation between 0.5 and 3ĝ€¯m has little effect on modelled soil temperatures, showing that using only two tiles can still be a valid representation of sites with a range of palsa elevations. Mire saturation is heavily dependent on landscape-scale drainage. Lateral conductive fluxes, while small, reduce the temperature splitting by ĝ1/4ĝ€¯1ĝ€¯ĝ C and correspond to the order of observed lateral degradation rates in peat plateau regions, indicating possible application in an area-based thaw model. Copyright:}, author = {Smith, Noah D. and Burke, Eleanor J. and Aas, Kjetil Schanke and Althuizen, Inge H.J. and Boike, Julia and Christiansen, Casper Tai and Etzelm{\"{u}}ller, Bernd and Friborg, Thomas and Lee, Hanna and Rumbold, Heather and Turton, Rachael H. and Westermann, Sebastian and Chadburn, Sarah E.}, doi = {10.5194/gmd-15-3603-2022}, file = {:Users/villekasurinen/Downloads/gmd-15-3603-2022.pdf:pdf}, issn = {19919603}, journal = {Geoscientific Model Development}, number = {9}, pages = {3603--3639}, title = {{Explicitly modelling microtopography in permafrost landscapes in a land surface model (JULES vn5.4_microtopography)}}, volume = {15}, year = {2022} } @article{gmd-15-395-2022, author = {Strebel, L and Bogena, H R and Vereecken, H and {Hendricks Franssen}, H.-J.}, doi = {10.5194/gmd-15-395-2022}, journal = {Geoscientific Model Development}, number = {2}, pages = {395--411}, title = {{Coupling the Community Land Model version 5.0 to the parallel data assimilation framework PDAF: description and applications}}, url = {https://gmd.copernicus.org/articles/15/395/2022/}, volume = {15}, year = {2022} } @article{Sungmin2022, abstract = {Droughts cause serious environmental and societal impacts, often aggravated by simultaneously occurring heat waves. Climate and vegetation play key roles in the evolution of drought-associated temperature anomalies, but their relative importance is largely unknown. Here, we present the hottest temperature anomalies during drought in subhumid and tree-dominated regions using observation-based, global data over 2001-15. These anomalies are mainly driven by a drought-related net radiation surplus and further amplified by forests' water-saving strategies that result in diminished evaporative cooling. By contrast, in semiarid and short-vegetation regions, drought-related temperature increases are smaller. The reduction of evaporative cooling is weak and net radiation increases only marginally due to high albedo over drought-stressed vegetation. Our findings highlight the importance of considering all interacting factors in understanding diverse mechanisms of concurrent drought-heat extremes across different climate regimes.}, author = {Sungmin, O. and Bastos, Ana and Reichstein, Markus and Li, Wantong and Denissen, Jasper and Graefen, Hanna and Orth, Rene}, doi = {10.1175/JCLI-D-21-0675.1}, file = {:Users/villekasurinen/Downloads/1520-0442-JCLI-D-21-0675.1.pdf:pdf}, issn = {15200442}, journal = {Journal of Climate}, keywords = {Atmosphere-land interaction,Drought,Extreme events,Hydrometeorology}, number = {17}, pages = {5677--5685}, title = {{The Role of Climate and Vegetation in Regulating Drought-Heat Extremes}}, volume = {35}, year = {2022} } @article{SZATNIEWSKA2022120248, abstract = {Recent changes in the floodplain forests of Central Europe, caused mainly by changes in hydrological management and the increased frequency of droughts due to climate change, have led to severe degradation of floodplain ecosystems. Our main objective was to determine the sensitivity of trees to drought by observing the response of the tree phenology, stem radial growth, and physiology (sap flow) of three predominant tree species, namely English oak, narrow-leaved ash, and common hornbeam, to the environmental variables (climate). Stem radial growth began before bud break in ring-porous oak and ash, whereas in diffuse-porous hornbeam, growth onset occurred after leaf formation. The early onset with intense growth during favorable months (April–May) observed in ring-porous species was a major prerequisite for the successful growth of oak and ash at this site. Tree water deficit (TWD), an indicator of stem hydration, was triggered by decreasing soil moisture in all species, and was most prominent in ash, followed by oak. Intriguingly, sap flow was decoupled from TWD in all species and was driven primarily by evaporative demand from the atmosphere. Oak was the least conservative in regulating sap flow under atmospheric drought followed by hornbeam, whereas ash was most restricted and reduced its transpiration during dry periods. In contrast, ash was characterized by the highest radial growth and growth-based water-use efficiency. The lower water storage capacity of oak and ash is likely compensated by deep rooting and drought avoidance strategies, respectively. Tree species that tend to use surface soil water could be severely limited by more extractive species such as hornbeam. Despite the contrasting leaf and wood phenology, stomatal control, and rooting depth among the studied floodplain tree species, they exhibited analogous sap flow and water storage dynamics responses to drier conditions that enabled them to co-exist in the South Moravian Region. Nevertheless, our results suggest that the severe droughts and human-induced alterations in groundwater pose serious threats to floodplain forests in Central Europe, with certain tree species being unable to adapt to these altered conditions.}, author = {Szatniewska, Justyna and Zavadilova, Ina and Nezval, Ondřej and Krejza, Jan and Petrik, Peter and {\v{C}}ater, Matja{\v{z}} and Stojanovi{\'{c}}, Marko}, doi = {https://doi.org/10.1016/j.foreco.2022.120248}, issn = {0378-1127}, journal = {Forest Ecology and Management}, keywords = { Diffuse‑porous species, Drought stress, Growth-based water use efficiency, Ring-porous species, Stem radial growth, Tree water deficit,Sap flow}, pages = {120248}, title = {{Species-specific growth and transpiration response to changing environmental conditions in floodplain forest}}, url = {https://www.sciencedirect.com/science/article/pii/S0378112722002420}, volume = {516}, year = {2022} } @article{egusphere-2022-213, author = {Thompson, R and Pisso, I}, doi = {10.5194/egusphere-2022-213}, journal = {EGUsphere}, pages = {1--18}, title = {{A Flexible Algorithm for Network Design Based on Information Theory}}, url = {https://egusphere.copernicus.org/preprints/egusphere-2022-213/}, volume = {2022}, year = {2022} } @article{Thompson2022, abstract = {The effect of the 2018 extreme meteorological conditions in Europe on methane (CH 4) emissions is examined using estimates from four atmospheric inversions calculated for the period 2005-2018. For most of Europe, we find no anomaly in 2018 compared to the 2005-2018 mean. However, we find a positive anomaly for the Netherlands in April, which coincided with positive temperature and soil moisture anomalies suggesting an increase in biogenic sources. We also find a negative anomaly for the Netherlands for September-October, which coincided with a negative anomaly in soil moisture, suggesting a decrease in soil sources. In addition, we find a positive anomaly for Serbia in spring, summer and autumn, which coincided with increases in temperature and soil moisture, again suggestive of changes in biogenic sources, and the annual emission for 2018 was 33 ± 38% higher than the 2005-2017 mean. These results indicate that CH 4 emissions from areas where the natural source is thought to be relatively small can still vary due to meteorological conditions. At the European scale though, the degree of variability over 2005-2018 was small, and there was negligible impact on the annual CH 4 emissions in 2018 despite the extreme meteorological conditions. This article is part of a discussion meeting issue 'Rising methane: is warming feeding warming? (part 2)'.}, author = {Thompson, R. L. and {Groot Zwaaftink}, C. D. and Brunner, D. and Tsuruta, A. and Aalto, T. and Raivonen, M. and Crippa, M. and Solazzo, E. and Guizzardi, D. and Regnier, P. and Maisonnier, M.}, doi = {10.1098/rsta.2020.0443}, file = {:Users/villekasurinen/Downloads/rsta.2020.0443.pdf:pdf}, issn = {1364503X}, journal = {Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences}, keywords = {CH 4,Europe,anomaly,atmospheric inversion,emissions,methane}, number = {2215}, pmid = {34865527}, title = {{Effects of extreme meteorological conditions in 2018 on European methane emissions estimated using atmospheric inversions}}, volume = {380}, year = {2022} } @article{atmos12020246, abstract = {We describe and implement a data selection algorithm aimed at identifying background atmospheric CO2 observations from in situ continuous measurements. Several selection criteria for detecting the background data have been developed and are currently used: the main objective of this work was to define a common methodology to extract the atmospheric background signal minimizing heterogeneities due to the use of different selection algorithms. The algorithm used in this study, (BaDS, Background Data Selection) was tested and optimized using data (from 2014 to 2018) from four Italian stations characterized by markedly different environmental conditions (i.e., mountain, coastal and marine): Plateau Rosa (PRS), Mt. Cimone (CMN), Capo Granitola (CGR) and Lampedusa (LMP). Their locations extend from the Alps to the central Mediterranean. The adopted algorithm proved to be effective in separating the local/regional from the background signal in the CO2 time series. About 6% of the data at LMP, 11% at PRS, 20–38% at CMN and 65% at CGR were identified as non-background. LMP and PRS can be used as reference sites for the central Mediterranean, while CMN and CGR were more impacted by regional sources and sinks. Finally, we discuss a possible application of BaDS screened data.}, author = {Trisolino, Pamela and di Sarra, Alcide and Sferlazzo, Damiano and Piacentino, Salvatore and Monteleone, Francesco and {Di Iorio}, Tatiana and Apadula, Francesco and Heltai, Daniela and Lanza, Andrea and Vocino, Antonio and di Torchiarolo, Luigi and Bonasoni, Paolo and Calzolari, Francescopiero and Busetto, Maurizio and Cristofanelli, Paolo}, doi = {10.3390/atmos12020246}, issn = {2073-4433}, journal = {Atmosphere}, number = {2}, title = {{Application of a Common Methodology to Select in Situ CO2 Observations Representative of the Atmospheric Background to an Italian Collaborative Network}}, url = {https://www.mdpi.com/2073-4433/12/2/246}, volume = {12}, year = {2021} } @article{f13101679, abstract = {A shift in management to improve the ecological function of mature plantations of exotic species can have important effects on the ecosystem climate mitigation potential. This study investigated the effect of two common forest management strategies for Scots pine (Pinus sylvestris L.) stands on the C storage after 15 years of management. Two pairs of forest stands on poor sandy soil and under the maritime influence in Brasschaat, Belgium, were observed as case studies. The observed forest management strategies were (i) thinning and group planting of oak saplings (Quercus robur L.) and (ii) clear cut, followed by replanting of young oak. For each stand, all forest C pools (aboveground biomass, belowground biomass, litter, and mineral soil) were determined. Results showed, surprisingly, no significant difference in the whole ecosystem C stock for both forest management strategies after 15 years of management. However, after the clear cut and the new plantation, the C in the top 30 cm layer of the mineral soil increased, while it decreased on the forest floor. For thinning with group planting, the C stocks reduced within the 10–30 cm soil layer without impact on the total soil C. Therefore, the shift in management did result in a different allocation of the belowground C, particularly after a clear cut. The results are not only relevant for the study region but also for managed Scots pine forests in neighboring regions of the Atlantic zone of Western Europe.}, author = {{Van Damme}, Freke and Mertens, Hana and Heinecke, Thilo and Lefevre, Lodewijk and {De Meulder}, Tim and Portillo-Estrada, Miguel and Roland, Marilyn and Gielen, Bert and Janssens, Ivan A and Verheyen, Kris and Campioli, Matteo}, doi = {10.3390/f13101679}, issn = {1999-4907}, journal = {Forests}, number = {10}, title = {{The Impact of Thinning and Clear Cut on the Ecosystem Carbon Storage of Scots Pine Stands under Maritime Influence in Flanders, Belgium}}, url = {https://www.mdpi.com/1999-4907/13/10/1679}, volume = {13}, year = {2022} } @article{essd-2022-175, author = {van der Woude, A M and de Kok, R and Smith, N and Luijkx, I T and Botia, S and Karstens, U and Kooijmans, L M J and Koren, G and Meijer, H and Steeneveld, G.-J. and Storm, I and Super, I and Scheeren, B A and Vermeulen, A and Peters, W}, doi = {10.5194/essd-2022-175}, journal = {Earth System Science Data Discussions}, pages = {1--38}, title = {{Near real-time CO$_2$ fluxes from CarbonTracker Europe for high resolution atmospheric modeling}}, url = {https://essd.copernicus.org/preprints/essd-2022-175/}, volume = {2022}, year = {2022} } @article{acp-22-2569-2022, author = {Vesala, T and Kohonen, K.-M. and Kooijmans, L M J and Praplan, A P and Folt{\'{y}}nov{\'{a}}, L and Kolari, P and Kulmala, M and B{\"{a}}ck, J and Nelson, D and Yakir, D and Zahniser, M and Mammarella, I}, doi = {10.5194/acp-22-2569-2022}, journal = {Atmospheric Chemistry and Physics}, number = {4}, pages = {2569--2584}, title = {{Long-term fluxes of carbonyl sulfide and their seasonality and interannual variability in a boreal forest}}, url = {https://acp.copernicus.org/articles/22/2569/2022/}, volume = {22}, year = {2022} } @article{VESTIN20224086015, abstract = {During 2010-2013, we investigated the effects of stump harvesting on greenhouse gas (GHG) fluxes of carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O) with the flux-gradient technique at four experimental plots in a hemiboreal forest in Sweden. All plots were clear-cut and soil scarified and two of the plots were additionally stump harvested. The two clear-cut plots served as control plots. Due to differences in topography, we had one wetter and one drier plot of each treatment. All plots exhibited substantial emissions of GHGs and we noted significant effects of wetness on CO2, CH4 and N2O fluxes within treatments and significant effects of stump harvesting on CO2 and N2O fluxes at the dry plots. The CO2 emissions were lower at the dry stump harvested plot than at the dry control, but when estimated emissions from the removed stumps were added, total CO2 emissions were higher at the stump harvested plot, indicating a small enhancement of soil respiration. In addition, we noted significant emissions of N2O at this plot. At the wet plots, CO2 emissions were higher at the stump harvested plot, also suggesting a treatment effect but differences in wetness and vegetation cover at these plots make this effect more uncertain. At the wet plots, we noted sustained periods (weeks to months) of net N2O uptake. During the year with simultaneous measurements of the abovementioned GHGs, GHG budgets were 1.224�103 and 1.442�103 gm-2 of CO2-equivalents at the wet and dry stump harvested plots, respectively, and 1.070�103 and 1.696�103 gm-2 of CO2-equivalents at the wet and dry control plots, respectively. CO2 fluxes dominated GHG budgets at all plots but N2O contributed with 17% at the dry stump harvested plot. For the full period 2010-2013, total carbon (CO2+CH4) budgets were 4.301�103 and 4.114�103 g m-2 of CO2-eqvivalents at the wet and dry stump harvest plots, respectively and 4.107�103 and 5.274�103 gm-2 of CO2-equivalents at the wet and dry control plots, respectively. Our results support recent studies suggesting that stump harvesting does not result in substantial increase in CO2 emissions but uncertainties regarding GHG fluxes (especially N2O) remain and more long-term measurements are needed before robust conclusions can be drawn.}, author = {Vestin, P and Molder, M and Kljun, N and Cai, Z and Hasan, A and Holst, J and Klemedtsson, L and Lindroth, A}, doi = {10.3832/ifor4086-015}, journal = {iForest - Biogeosciences and Forestry}, keywords = { CH4, Climate Change Mitigation, Forest Management, Greenhouse Gas Budget, Hemiboreal Forest, N2O, Stump Harvesting,CO2}, number = {3}, pages = {148--162}, title = {{Impacts of stump harvesting on carbon dioxide, methane and nitrous oxide fluxes}}, url = {https://iforest.sisef.org/contents/?id=ifor4086-015}, year = {2022} } @article{bg-19-2805-2022, author = {Walther, S and Besnard, S and Nelson, J A and El-Madany, T S and Migliavacca, M and Weber, U and Carvalhais, N and Ermida, S L and Br{\"{u}}mmer, C and Schrader, F and Prokushkin, A S and Panov, A V and Jung, M}, doi = {10.5194/bg-19-2805-2022}, journal = {Biogeosciences}, number = {11}, pages = {2805--2840}, title = {{Technical note: A view from space on global flux towers by MODIS and Landsat: the FluxnetEO data set}}, url = {https://bg.copernicus.org/articles/19/2805/2022/}, volume = {19}, year = {2022} } @article{Wang2022, abstract = { Deforestation has a wide range of effects on hydrological and geochemical processes. Dissolved organic carbon (DOC) dynamics, a sensitive environmental change indicator, is expected to be affected by deforestation, with changes in atmospheric sulfur (S) deposition compounding this. However, how precisely anthropogenic disturbance (deforestation) under a declining atmospheric S input scenario affects the underlying spatiotemporal dynamics and relationships of river DOC and sulfate with hydro-climatological variables e.g., stream water temperature, runoff, pH, total dissolved iron (Fe tot ), and calcium (Ca 2+ ) remains unclear. We, therefore, examined this issue within the TERENO W{\"{u}}stebach catchment (Eifel, Germany), where partial deforestation had taken place in 2013. Wavelet transform coherence (WTC) analysis was applied based on a 10-year time series (2010–2020) from three sampling stations, whose (sub) catchment areas have different proportions of deforested area (W10: 31%, W14: 25%, W17: 3%). We found that water temperature and DOC, sulfate, and Fe tot concentrations showed distinct seasonal patterns, with DOC averaging concentrations ranging from 2.23 (W17) to 4.56 (W10) mg L –1 and sulfate concentration ranging from 8.04 (W10) to 10.58 (W17) mg L –1 . After clear-cut, DOC significantly increased by 59, 58% in the mainstream (W10, W14), but only 26% in the reference stream. WTC results indicated that DOC was negatively correlated with runoff and sulfate, but positively correlated with temperature, Ca 2+ , and Fe tot . The negative correlation between DOC with runoff and sulfate was apparent over the whole examined 10-year period in W17 but did end in W10 and W14 after the deforestation. Sulfate (SO 4 ) was highly correlated with stream water temperature, runoff, and Fe tot in W10 and W14 and with a longer lag time than W17. Additionally, pH was stronger correlated (higher R 2 ) with sulfate and DOC in W17 than in W10 and W14. In conclusion, WTC analysis indicates that within this low mountainous forest catchment deforestation levels over 25% (W10 and W14) affected the coupling of S and C cycling substantially more strongly than “natural” environmental changes as observed in W17. }, author = {Wang, Qiqi and Qu, Yuquan and Robinson, Kerri-Leigh and Bogena, Heye and Graf, Alexander and Vereecken, Harry and Tietema, Albert and Bol, Roland}, doi = {10.3389/ffgc.2022.1044447}, file = {:Users/villekasurinen/Downloads/ffgc-05-1044447.pdf:pdf}, issn = {2624893X}, journal = {Frontiers in Forests and Global Change}, keywords = {dissolved organic carbon, sulfate, runoff, deforestation, wavelet transform coherence}, number = {November}, pages = {1--14}, title = {{Deforestation alters dissolved organic carbon and sulfate dynamics in a mountainous headwater catchment—A wavelet analysis}}, volume = {5}, year = {2022} } @article{WANG2022156326, abstract = {Net Ecosystem Production (NEP) of forests is the net carbon dioxide (CO2) fluxes between land and the atmosphere due to forests' biogeochemical processes. NEP varies with natural drivers such as precipitation, air temperature, solar radiation, plant functional type (PFT), and soil texture, which affect the gross primary production and ecosystem respiration, and thus the net C sequestration. It is also known that deposition of sulphur and nitrogen influences NEP in forest ecosystems. These drivers' respective, unique effects on NEP, however, are often difficult to be individually identified by conventional bivariate analysis. Here we show that by analyzing 22 forest sites with 231 site-year data acquired from FLUXNET database across Europe for the years 2000–2014, the individual, unique effects of these drivers on annual forest CO2 fluxes can be disentangled using Generalized Additive Models (GAM) for nonlinear regression analysis. We show that S and N deposition have substantial impacts on NEP, where S deposition above 5 kg S ha−1 yr−1 can significantly reduce NEP, and N deposition around 22 kg N ha−1 yr−1 has the highest positive effect on NEP. Our results suggest that air quality management of S and N is crucial for maintaining healthy biogeochemical functions of forests to mitigate climate change. Furthermore, the empirical models we developed for estimating NEP of forests can serve as a forest management tool in the context of climate change mitigation. Potential applications include the assessment of forest carbon fluxes in the REDD+ framework of the UNFCCC.}, author = {Wang, You-Ren and Buchmann, Nina and Hessen, Dag O and Stordal, Frode and Erisman, Jan Willem and Vollsnes, Ane Victoria and Andersen, Tom and Dolman, Han}, doi = {https://doi.org/10.1016/j.scitotenv.2022.156326}, issn = {0048-9697}, journal = {Science of The Total Environment}, keywords = { Empirical biogeochemical models, GAM, GPP, NEE, RECO,Forest carbon uptake}, pages = {156326}, title = {{Disentangling effects of natural and anthropogenic drivers on forest net ecosystem production}}, url = {https://www.sciencedirect.com/science/article/pii/S0048969722034234}, volume = {839}, year = {2022} } @article{bg-19-5287-2022, author = {Wintjen, P and Schrader, F and Schaap, M and Beudert, B and Kranenburg, R and Br{\"{u}}mmer, C}, doi = {10.5194/bg-19-5287-2022}, journal = {Biogeosciences}, number = {22}, pages = {5287--5311}, title = {{Forest--atmosphere exchange of reactive nitrogen in a remote region -- Part II: Modeling annual budgets}}, url = {https://bg.copernicus.org/articles/19/5287/2022/}, volume = {19}, year = {2022} } @article{bg-19-4315-2022, author = {Yu, X and Orth, R and Reichstein, M and Bahn, M and Klosterhalfen, A and Knohl, A and Koebsch, F and Migliavacca, M and Mund, M and Nelson, J A and Stocker, B D and Walther, S and Bastos, A}, doi = {10.5194/bg-19-4315-2022}, journal = {Biogeosciences}, number = {17}, pages = {4315--4329}, title = {{Contrasting drought legacy effects on gross primary productivity in a mixed versus pure beech forest}}, url = {https://bg.copernicus.org/articles/19/4315/2022/}, volume = {19}, year = {2022} } @article{YUAN2022109115, abstract = {Wetland CH4 emissions are among the most uncertain components of the global CH4 budget. The complex nature of wetland CH4 processes makes it challenging to identify causal relationships for improving our understanding and predictability of CH4 emissions. In this study, we used the flux measurements of CH4 from eddy covariance towers (30 sites from 4 wetlands types: bog, fen, marsh, and wet tundra) to construct a causality-constrained machine learning (ML) framework to explain the regulative factors and to capture CH4 emissions at sub-seasonal scale. We found that soil temperature is the dominant factor for CH4 emissions in all studied wetland types. Ecosystem respiration (CO2) and gross primary productivity exert controls at bog, fen, and marsh sites with lagged responses of days to weeks. Integrating these asynchronous environmental and biological causal relationships in predictive models significantly improved model performance. More importantly, modeled CH4 emissions differed by up to a factor of 4 under a +1°C warming scenario when causality constraints were considered. These results highlight the significant role of causality in modeling wetland CH4 emissions especially under future warming conditions, while traditional data-driven ML models may reproduce observations for the wrong reasons. Our proposed causality-guided model could benefit predictive modeling, large-scale upscaling, data gap-filling, and surrogate modeling of wetland CH4 emissions within earth system land models.}, author = {Yuan, Kunxiaojia and Zhu, Qing and Li, Fa and Riley, William J and Torn, Margaret and Chu, Housen and McNicol, Gavin and Chen, Min and Knox, Sara and Delwiche, Kyle and Wu, Huayi and Baldocchi, Dennis and Ma, Hongxu and Desai, Ankur R and Chen, Jiquan and Sachs, Torsten and Ueyama, Masahito and Sonnentag, Oliver and Helbig, Manuel and Tuittila, Eeva-Stiina and Jurasinski, Gerald and Koebsch, Franziska and Campbell, David and Schmid, Hans Peter and Lohila, Annalea and Goeckede, Mathias and Nilsson, Mats B and Friborg, Thomas and Jansen, Joachim and Zona, Donatella and Euskirchen, Eugenie and Ward, Eric J and Bohrer, Gil and Jin, Zhenong and Liu, Licheng and Iwata, Hiroki and Goodrich, Jordan and Jackson, Robert}, doi = {https://doi.org/10.1016/j.agrformet.2022.109115}, issn = {0168-1923}, journal = {Agricultural and Forest Meteorology}, keywords = { Causal inference, Machine learning, Wetlands,Eddy covariance CH emission}, pages = {109115}, title = {{Causality guided machine learning model on wetland CH4 emissions across global wetlands}}, url = {https://www.sciencedirect.com/science/article/pii/S0168192322003021}, volume = {324}, year = {2022} } @article{gi-11-223-2022, author = {Zawilski, B M}, doi = {10.5194/gi-11-223-2022}, journal = {Geoscientific Instrumentation, Methods and Data Systems}, number = {2}, pages = {223--234}, title = {{The soil heat flux sensor functioning checks, imbalances' origins, and forgotten energies}}, url = {https://gi.copernicus.org/articles/11/223/2022/}, volume = {11}, year = {2022} } @article{gi-11-163-2022, author = {Zawilski, B M}, doi = {10.5194/gi-11-163-2022}, journal = {Geoscientific Instrumentation, Methods and Data Systems}, number = {1}, pages = {163--182}, title = {{Wind speed influences corrected Autocalibrated Soil Evapo-respiration Chamber (ASERC) evaporation measures}}, url = {https://gi.copernicus.org/articles/11/163/2022/}, volume = {11}, year = {2022} } @article{Zenone2022, abstract = {Background: The evaporative fraction (EF) represents an important biophysical parameter reflecting the distribution of surface available energy. In this study, we investigated the daily and seasonal patterns of EF in a multi-year corn cultivation located in southern Italy and evaluated the performance of five machine learning (ML) classes of algorithms: the linear regression (LR), regression tree (RT), support vector machine (SVM), ensembles of tree (ETs) and Gaussian process regression (GPR) to predict the EF at daily time step. The adopted methodology consisted of three main steps that include: (i) selection of the EF predictors; (ii) comparison of the different classes of ML; (iii) application, cross-validation of the selected ML algorithms and comparison with the observed data. Results: Our results indicate that SVM and GPR were the best classes of ML at predicting the EF, with a total of four different algorithms: cubic SVM, medium Gaussian SVM, the Matern 5/2 GPR, and the rational quadratic GPR. The comparison between observed and predicted EF in all four algorithms, during the training phase, were within the 95% confidence interval: the R2 value between observed and predicted EF was 0.76 (RMSE 0.05) for the medium Gaussian SVM, 0.99 (RMSE 0.01) for the rational quadratic GPR, 0.94 (RMSE 0.02) for the Matern 5/2 GPR, and 0.83 (RMSE 0.05) for the cubic SVM algorithms. Similar results were obtained during the testing phase. The results of the cross-validation analysis indicate that the R2 values obtained between all iterations for each of the four adopted ML algorithms were basically constant, confirming the ability of ML as a tool to predict EF. Conclusion: ML algorithms represent a valid alternative able to predict the EF especially when remote sensing data are not available, or the sky conditions are not suitable. The application to different geographical areas, or crops, requires further development of the model based on different data sources of soils, climate, and cropping systems.}, author = {Zenone, Terenzio and Vitale, Luca and Famulari, Daniela and Magliulo, Vincenzo}, doi = {10.1186/s13717-022-00400-1}, file = {:Users/villekasurinen/Downloads/s13717-022-00400-1.pdf:pdf}, issn = {21921709}, journal = {Ecological Processes}, keywords = {Artificial intelligence,Eddy covariance,Energy flux,Evapotranspiration}, number = {1}, pages = {1--14}, publisher = {Springer Berlin Heidelberg}, title = {{Application of machine learning techniques to simulate the evaporative fraction and its relationship with environmental variables in corn crops}}, url = {https://doi.org/10.1186/s13717-022-00400-1}, volume = {11}, year = {2022} } @article{ZHANG2022157856, abstract = {Annual gross primary productivity (AGPP) of terrestrial ecosystems is the largest carbon flux component in ecosystems; however, it's unclear whether photosynthetic capacity or phenology dominates interannual variation of AGPP, and a better understanding of this could contribute to estimation of carbon sinks and their interactions with climate change. In this study, observed GPP data of 494 site-years from 39 eddy covariance sites in Northern Hemisphere were used to investigate mechanisms of interannual variation of AGPP. This study first decomposed AGPP into three seasonal dynamic attribute parameters (growing season length (CUP), maximum daily GPP (GPPmax), and the ratio of mean daily GPP to GPPmax ($\alpha$GPP)), and then decomposed AGPP into mean leaf area index (LAIm) and annual photosynthetic capacity per leaf area (AGPPlm). Furthermore, GPPmax was decomposed into leaf area index of DOYmax (the day when GPPmax appeared) (LAImax) and photosynthesis per leaf area of DOYmax (GPPlmax). Relative contributions of parameters to AGPP and GPPmax were then calculated. Finally, environmental variables of DOYmax were extracted to analyze factors influencing interannual variation of GPPlmax. Trends of AGPP in 39 ecosystems varied from −65.23 to 53.05 g C m−2 yr−2, with the mean value of 6.32 g C m−2 yr−2. Photosynthetic capacity (GPPmax and AGPPlm), not CUP or LAI, was the main factor dominating interannual variation of AGPP. GPPlmax determined the interannual variation of GPPmax, and temperature, water, and radiation conditions of DOYmax affected the interannual variation of GPPlmax. This study used the cascade relationship of “environmental variables-GPPlmax-GPPmax-AGPP” to explain the mechanism of interannual variation of AGPP, which can provide new ideas for the AGPP estimation based on seasonal dynamic of GPP.}, author = {Zhang, Weikang and Yu, Guirui and Chen, Zhi and Zhu, Xianjin and Han, Lang and Liu, Zhaogang and Lin, Yong and Han, Shijie and Sha, Liqing and Wang, Huimin and Wang, Yanfen and Yan, Junhua and Zhang, Yiping and Gharun, Mana}, doi = {https://doi.org/10.1016/j.scitotenv.2022.157856}, issn = {0048-9697}, journal = {Science of The Total Environment}, keywords = { Environmental variables, Interannual variation, Maximum daily GPP, Photosynthesis per leaf area,Annual gross primary productivity}, pages = {157856}, title = {{Photosynthetic capacity dominates the interannual variation of annual gross primary productivity in the Northern Hemisphere}}, url = {https://www.sciencedirect.com/science/article/pii/S0048969722049555}, volume = {849}, year = {2022} } @article{f13101721, abstract = {Forests sequester atmospheric carbon dioxide (CO2) which is important for climate mitigation. Net ecosystem production (NEP) varies significantly across forests in different regions depending on the dominant tree species, stand age, and environmental factors. Therefore, it is important to evaluate forest NEP and its potential changes under climate change in different regions to inform forestry policy making. Norway spruce (Picea abies) is the most prevalent species in conifer forests throughout Europe. Here, we focused on Norway spruce forests and used eddy covariance-based observations of CO2 fluxes and other variables from eight sites to build a XGBoost machine learning model for NEP estimation. The NEP values from the study sites varied between −296 (source) and 1253 (sink) g C m−2 yr−1. Overall, among the tested variables, air temperature was the most important factor driving NEP variations, followed by global radiation and stand age, while precipitation had a very limited contribution to the model. The model was used to predict the NEP of mature Norway spruce forests in different regions within Europe. The NEP median value was 494 g C m−2 yr−1 across the study areas, with higher NEP values, up to >800 g C m−2 yr−1, in lower latitude regions. Under the “middle-of-the-road” SSP2-4.5 scenario, the NEP values tended to be greater in almost all the studied regions by 2060 with the estimated median of NEP changes in 2041–2060 to be +45 g C m−2 yr−1. Our results indicate that Norway spruce forests show high productivity in a wide area of Europe with potentially future NEP enhancement. However, due to the limitations of the data, the potential decrease in NEP induced by temperature increases beyond the photosynthesis optima and frequent ecosystem disturbances (e.g., drought, bark beetle infestation, etc.) still needs to be evaluated.}, author = {Zhao, Junbin and Lange, Holger and Meissner, Helge}, doi = {10.3390/f13101721}, issn = {1999-4907}, journal = {Forests}, number = {10}, title = {{Estimating Carbon Sink Strength of Norway Spruce Forests Using Machine Learning}}, url = {https://www.mdpi.com/1999-4907/13/10/1721}, volume = {13}, year = {2022} } @article{ZHAO2022109112, abstract = {The boreal forest is an important global carbon (C) sink. Since low soil nitrogen (N) availability is commonly a key constraint on forest productivity, the prevalent view is that increased N input enhances its C sink-strength. This understanding however relies primarily on observations of increased aboveground tree biomass and soil C stock following N fertilization, whereas empirical data evaluating the effects on the whole ecosystem-scale C balance are lacking. Here we use a unique long-term experiment consisting of paired forest stands with eddy covariance measurements to explore the effect of ecosystem-scale N fertilization on the C balance of a managed boreal pine forest. We find that the annual C uptake (i.e. net ecosystem production, NEP) at the fertilized stand was 16 ± 2% greater relative to the control stand by the end of the first decade of N addition. Subsequently, the ratio of NEP between the fertilized and control stand remained at a stable level during the following five years with an average NEP to N response of 7 ± 1 g C per g N. Our study reveals that this non-linear response of NEP to long-term N fertilization was the result of a cross-seasonal feedback between the N-induced increases in both growing-season C uptake and subsequent winter C emission. We further find that one decade of N addition altered the sensitivity of ecosystem C fluxes to key environmental drivers resulting in divergent responses to weather patterns. Thus, our study highlights the need to account for ecosystem-scale responses to perturbations to improve our understanding of nitrogen-carbon-climate feedbacks in boreal forests.}, author = {Zhao, Peng and Chi, Jinshu and Nilsson, Mats B and L{\"{o}}fvenius, Mikaell Ottosson and H{\"{o}}gberg, Peter and Jocher, Georg and Lim, Hyungwoo and M{\"{a}}kel{\"{a}}, Annikki and Marshall, John and Ratcliffe, Joshua and Tian, Xianglin and N{\"{a}}sholm, Torgny and Lundmark, Tomas and Linder, Sune and Peichl, Matthias}, doi = {https://doi.org/10.1016/j.agrformet.2022.109112}, issn = {0168-1923}, journal = {Agricultural and Forest Meteorology}, keywords = { Carbon sequestration, Climate change, Eddy covariance, Forest management, Nitrogen fertilization,Boreal forest}, pages = {109112}, title = {{Long-term nitrogen addition raises the annual carbon sink of a boreal forest to a new steady-state}}, url = {https://www.sciencedirect.com/science/article/pii/S0168192322002994}, volume = {324}, year = {2022} } @article{https://doi.org/10.1111/gcb.16094, abstract = {Abstract The past decades have witnessed an increase in dissolved organic carbon (DOC) concentrations in the catchments of the Northern Hemisphere. Increasing terrestrial productivity and changing hydrology may be reasons for the increases in DOC concentration. The aim of this study is to investigate the impacts of increased terrestrial productivity and changed hydrology following climate change on DOC concentrations. We tested and quantified the effects of gross primary production (GPP), ecosystem respiration (RE) and discharge on DOC concentrations in boreal catchments over 3 years. As catchment characteristics can regulate the extent of rising DOC concentrations caused by the regional or global environmental changes, we selected four catchments with different sizes (small, medium and large) and landscapes (forest, mire and forest-mire mixed). We applied multiple models: Wavelet coherence analysis detected the delay-effects of terrestrial productivity and discharge on aquatic DOC variations of boreal catchments; thereafter, the distributed-lag linear models quantified the contributions of each factor on DOC variations. Our results showed that the combined impacts of terrestrial productivity and discharge explained 62\% of aquatic DOC variations on average across all sites, whereas discharge, gross primary production (GPP) and RE accounted for 26\%, 22\% and 3\%, respectively. The impact of GPP and discharge on DOC changes was directly related to catchment size: GPP dominated DOC fluctuations in small catchments (<1 km2), whereas discharge controlled DOC variations in big catchments (>1 km2). The direction of the relation between GPP and discharge on DOC varied. Increasing RE always made a positive contribution to DOC concentration. This study reveals that climate change-induced terrestrial greening and shifting hydrology change the DOC export from terrestrial to aquatic ecosystems. The work improves our mechanistic understanding of surface water DOC regulation in boreal catchments and confirms the importance of DOC fluxes in regulating ecosystem C budgets.}, author = {Zhu, Xudan and Chen, Liang and Pumpanen, Jukka and Ojala, Anne and Zobitz, John and Zhou, Xuan and Laudon, Hjalmar and Palviainen, Marjo and Neitola, Kimmo and Berninger, Frank}, doi = {https://doi.org/10.1111/gcb.16094}, journal = {Global Change Biology}, keywords = { DOC, GPP, RE, catchment size, discharge, landscape, terrestrial productivity,boreal catchments}, number = {8}, pages = {2764--2778}, title = {{The role of terrestrial productivity and hydrology in regulating aquatic dissolved organic carbon concentrations in boreal catchments}}, url = {https://onlinelibrary.wiley.com/doi/abs/10.1111/gcb.16094}, volume = {28}, year = {2022} }