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277 results on '"Parmentier, Frans Jan W."'

1. Decadal increases in carbon uptake offset by respiratory losses across northern permafrost ecosystems

Author

See, Craig R, Virkkala, Anna-Maria, Natali, Susan M, Rogers, Brendan M, Mauritz, Marguerite, Biasi, Christina, Bokhorst, Stef, Boike, Julia, Bret-Harte, M Syndonia, Celis, Gerardo, Chae, Namyi, Christensen, Torben R, Murner (Connon), Sara June, Dengel, Sigrid, Dolman, Han, Edgar, Colin W, Elberling, Bo, Emmerton, Craig A, Euskirchen, Eugénie S, Göckede, Mathias, Grelle, Achim, Heffernan, Liam, Helbig, Manuel, Holl, David, Humphreys, Elyn, Iwata, Hiroki, Järveoja, Järvi, Kobayashi, Hideki, Kochendorfer, John, Kolari, Pasi, Kotani, Ayumi, Kutzbach, Lars, Kwon, Min Jung, Lathrop, Emma R, López-Blanco, Efrén, Mammarella, Ivan, Marushchak, Maija E, Mastepanov, Mikhail, Matsuura, Yojiro, Merbold, Lutz, Meyer, Gesa, Minions, Christina, Nilsson, Mats B, Nojeim, Julia, Oberbauer, Steven F, Olefeldt, David, Park, Sang-Jong, Parmentier, Frans-Jan W, Peichl, Matthias, Peter, Darcy, Petrov, Roman, Poyatos, Rafael, Prokushkin, Anatoly S, Quinton, William, Rodenhizer, Heidi, Sachs, Torsten, Savage, Kathleen, Schulze, Christopher, Sjögersten, Sofie, Sonnentag, Oliver, St. Louis, Vincent L, Torn, Margaret S, Tuittila, Eeva-Stiina, Ueyama, Masahito, Varlagin, Andrej, Voigt, Carolina, Watts, Jennifer D, Zona, Donatella, Zyryanov, Viacheslav I, and Schuur, Edward AG

Subjects
Agricultural, Veterinary and Food Sciences, Biological Sciences, Ecology, Forestry Sciences, Atmospheric Sciences, Physical Geography and Environmental Geoscience, Environmental Science and Management
Abstract

Tundra and boreal ecosystems encompass the northern circumpolar permafrost region and are experiencing rapid environmental change with important implications for the global carbon (C) budget. We analysed multi-decadal time series containing 302 annual estimates of carbon dioxide (CO2) flux across 70 permafrost and non-permafrost ecosystems, and 672 estimates of summer CO2 flux across 181 ecosystems. We find an increase in the annual CO2 sink across non-permafrost ecosystems but not permafrost ecosystems, despite similar increases in summer uptake. Thus, recent non-growing-season CO2 losses have substantially impacted the CO2 balance of permafrost ecosystems. Furthermore, analysis of interannual variability reveals warmer summers amplify the C cycle (increase productivity and respiration) at putatively nitrogen-limited sites and at sites less reliant on summer precipitation for water use. Our findings suggest that water and nutrient availability will be important predictors of the C-cycle response of these ecosystems to future warming.

Published
2024

2. Integration of a Frost Mortality Scheme Into the Demographic Vegetation Model FATES

Author

Lambert, Marius SA, Tang, Hui, S., Kjetil, Stordal, Frode, Fisher, Rosie A, Bjerke, Jarle W, Holm, Jennifer A, and Parmentier, Frans‐Jan W

Subjects
Earth Sciences, Atmospheric Sciences, Geoinformatics, Good Health and Well Being, Climate Action, frost, mortality, land surface, model, hardening, Atmospheric sciences
Abstract

Frost is damaging to plants when air temperature drops below their tolerance threshold. The set of mechanisms used by cold-tolerant plants to withstand freezing is called “hardening” and typically take place in autumn to protect against winter damage. The recent incorporation of a hardening scheme in the demographic vegetation model FATES opens up the possibility to investigate frost mortality to vegetation. Previously, the hardening scheme was used to improve hydraulic processes in cold-tolerant plants. In this study, we expand upon the existing hardening scheme by implementing hardiness-dependent frost mortality into CLM5.0-FATES to study the impacts of frost on vegetation in temperate and boreal sites from 1950 to 2015. Our results show that the original freezing mortality approach of FATES, where each plant type had a fixed freezing tolerance threshold—an approach common to many other dynamic vegetation models, was restricted to predicting plant type distribution. The main results emerging from the new scheme are a high autumn and spring frost mortality, especially at colder sites, and increasing mid-winter frost mortality due to global warming, especially at warmer sites. We demonstrate that the new frost scheme is a major step forward in dynamically representing vegetation in ESMs by for the first time including a level of frost tolerance that is responding to the environment and includes some level of cost (implicitly) and benefit. By linking hardening and frost mortality in a land surface model, we open new ways to explore the impact of frost events in the context of global warming.

Published
2023

3. The ABCflux database: Arctic–boreal CO2 flux observations and ancillary information aggregated to monthly time steps across terrestrial ecosystems

Author

Virkkala, Anna-Maria, Natali, Susan M, Rogers, Brendan M, Watts, Jennifer D, Savage, Kathleen, Connon, Sara June, Mauritz, Marguerite, Schuur, Edward AG, Peter, Darcy, Minions, Christina, Nojeim, Julia, Commane, Roisin, Emmerton, Craig A, Goeckede, Mathias, Helbig, Manuel, Holl, David, Iwata, Hiroki, Kobayashi, Hideki, Kolari, Pasi, López-Blanco, Efrén, Marushchak, Maija E, Mastepanov, Mikhail, Merbold, Lutz, Parmentier, Frans-Jan W, Peichl, Matthias, Sachs, Torsten, Sonnentag, Oliver, Ueyama, Masahito, Voigt, Carolina, Aurela, Mika, Boike, Julia, Celis, Gerardo, Chae, Namyi, Christensen, Torben R, Bret-Harte, M Syndonia, Dengel, Sigrid, Dolman, Han, Edgar, Colin W, Elberling, Bo, Euskirchen, Eugenie, Grelle, Achim, Hatakka, Juha, Humphreys, Elyn, Järveoja, Järvi, Kotani, Ayumi, Kutzbach, Lars, Laurila, Tuomas, Lohila, Annalea, Mammarella, Ivan, Matsuura, Yojiro, Meyer, Gesa, Nilsson, Mats B, Oberbauer, Steven F, Park, Sang-Jong, Petrov, Roman, Prokushkin, Anatoly S, Schulze, Christopher, St. Louis, Vincent L, Tuittila, Eeva-Stiina, Tuovinen, Juha-Pekka, Quinton, William, Varlagin, Andrej, Zona, Donatella, and Zyryanov, Viacheslav I

Subjects
Earth Sciences, Physical Geography and Environmental Geoscience, Atmospheric Sciences, Geoinformatics, Geochemistry, Atmospheric sciences, Physical geography and environmental geoscience
Abstract

Past efforts to synthesize and quantify the magnitude and change in carbon dioxide (CO2) fluxes in terrestrial ecosystems across the rapidly warming Arctic-boreal zone (ABZ) have provided valuable information but were limited in their geographical and temporal coverage. Furthermore, these efforts have been based on data aggregated over varying time periods, often with only minimal site ancillary data, thus limiting their potential to be used in large-scale carbon budget assessments. To bridge these gaps, we developed a standardized monthly database of Arctic-boreal CO2 fluxes (ABCflux) that aggregates in situ measurements of terrestrial net ecosystem CO2 exchange and its derived partitioned component fluxes: gross primary productivity and ecosystem respiration. The data span from 1989 to 2020 with over 70 supporting variables that describe key site conditions (e.g., vegetation and disturbance type), micrometeorological and environmental measurements (e.g., air and soil temperatures), and flux measurement techniques. Here, we describe these variables, the spatial and temporal distribution of observations, the main strengths and limitations of the database, and the potential research opportunities it enables. In total, ABCflux includes 244 sites and 6309 monthly observations; 136 sites and 2217 monthly observations represent tundra, and 108 sites and 4092 observations represent the boreal biome. The database includes fluxes estimated with chamber (19% of the monthly observations), snow diffusion (3%) and eddy covariance (78%) techniques. The largest number of observations were collected during the climatological summer (June-August; 32%), and fewer observations were available for autumn (September-October; 25%), winter (December-February; 18%), and spring (March-May; 25%). ABCflux can be used in a wide array of empirical, remote sensing and modeling studies to improve understanding of the regional and temporal variability in CO2 fluxes and to better estimate the terrestrial ABZ CO2 budget. ABCflux is openly and freely available online (Virkkala et al., 2021b, 10.3334/ORNLDAAC/1934). Copyright:

Published
2022

4. Large loss of CO2 in winter observed across the northern permafrost region

Author

Natali, Susan M, Watts, Jennifer D, Rogers, Brendan M, Potter, Stefano, Ludwig, Sarah M, Selbmann, Anne-Katrin, Sullivan, Patrick F, Abbott, Benjamin W, Arndt, Kyle A, Birch, Leah, Björkman, Mats P, Bloom, A Anthony, Celis, Gerardo, Christensen, Torben R, Christiansen, Casper T, Commane, Roisin, Cooper, Elisabeth J, Crill, Patrick, Czimczik, Claudia, Davydov, Sergey, Du, Jinyang, Egan, Jocelyn E, Elberling, Bo, Euskirchen, Eugenie S, Friborg, Thomas, Genet, Hélène, Göckede, Mathias, Goodrich, Jordan P, Grogan, Paul, Helbig, Manuel, Jafarov, Elchin E, Jastrow, Julie D, Kalhori, Aram AM, Kim, Yongwon, Kimball, John S, Kutzbach, Lars, Lara, Mark J, Larsen, Klaus S, Lee, Bang-Yong, Liu, Zhihua, Loranty, Michael M, Lund, Magnus, Lupascu, Massimo, Madani, Nima, Malhotra, Avni, Matamala, Roser, McFarland, Jack, McGuire, A David, Michelsen, Anders, Minions, Christina, Oechel, Walter C, Olefeldt, David, Parmentier, Frans-Jan W, Pirk, Norbert, Poulter, Ben, Quinton, William, Rezanezhad, Fereidoun, Risk, David, Sachs, Torsten, Schaefer, Kevin, Schmidt, Niels M, Schuur, Edward AG, Semenchuk, Philipp R, Shaver, Gaius, Sonnentag, Oliver, Starr, Gregory, Treat, Claire C, Waldrop, Mark P, Wang, Yihui, Welker, Jeffrey, Wille, Christian, Xu, Xiaofeng, Zhang, Zhen, Zhuang, Qianlai, and Zona, Donatella

Subjects
Agricultural, Veterinary and Food Sciences, Biological Sciences, Forestry Sciences, Climate Action, Atmospheric Sciences, Physical Geography and Environmental Geoscience, Environmental Science and Management
Abstract

Recent warming in the Arctic, which has been amplified during the winter1-3, greatly enhances microbial decomposition of soil organic matter and subsequent release of carbon dioxide (CO2)4. However, the amount of CO2 released in winter is highly uncertain and has not been well represented by ecosystem models or by empirically-based estimates5,6. Here we synthesize regional in situ observations of CO2 flux from arctic and boreal soils to assess current and future winter carbon losses from the northern permafrost domain. We estimate a contemporary loss of 1662 Tg C yr-1 from the permafrost region during the winter season (October through April). This loss is greater than the average growing season carbon uptake for this region estimated from process models (-1032 Tg C yr-1). Extending model predictions to warmer conditions in 2100 indicates that winter CO2 emissions will increase 17% under a moderate mitigation scenario-Representative Concentration Pathway (RCP) 4.5-and 41% under business-as-usual emissions scenario-RCP 8.5. Our results provide a new baseline for winter CO2 emissions from northern terrestrial regions and indicate that enhanced soil CO2 loss due to winter warming may offset growing season carbon uptake under future climatic conditions.

Published
2019

6. Vegetation type is an important predictor of the arctic summer land surface energy budget

Author

Oehri, Jacqueline, Schaepman-Strub, Gabriela, Kim, Jin-Soo, Grysko, Raleigh, Kropp, Heather, Grünberg, Inge, Zemlianskii, Vitalii, Sonnentag, Oliver, Euskirchen, Eugénie S., Reji Chacko, Merin, Muscari, Giovanni, Blanken, Peter D., Dean, Joshua F., di Sarra, Alcide, Harding, Richard J., Sobota, Ireneusz, Kutzbach, Lars, Plekhanova, Elena, Riihelä, Aku, Boike, Julia, Miller, Nathaniel B., Beringer, Jason, López-Blanco, Efrén, Stoy, Paul C., Sullivan, Ryan C., Kejna, Marek, Parmentier, Frans-Jan W., Gamon, John A., Mastepanov, Mikhail, Wille, Christian, Jackowicz-Korczynski, Marcin, Karger, Dirk N., Quinton, William L., Putkonen, Jaakko, van As, Dirk, Christensen, Torben R., Hakuba, Maria Z., Stone, Robert S., Metzger, Stefan, Vandecrux, Baptiste, Frost, Gerald V., Wild, Martin, Hansen, Birger, Meloni, Daniela, Domine, Florent, te Beest, Mariska, Sachs, Torsten, Kalhori, Aram, Rocha, Adrian V., Williamson, Scott N., Morris, Sara, Atchley, Adam L., Essery, Richard, Runkle, Benjamin R. K., Holl, David, Riihimaki, Laura D., Iwata, Hiroki, Schuur, Edward A. G., Cox, Christopher J., Grachev, Andrey A., McFadden, Joseph P., Fausto, Robert S., Göckede, Mathias, Ueyama, Masahito, Pirk, Norbert, de Boer, Gijs, Bret-Harte, M. Syndonia, Leppäranta, Matti, Steffen, Konrad, Friborg, Thomas, Ohmura, Atsumu, Edgar, Colin W., Olofsson, Johan, and Chambers, Scott D.

Published
2022
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7. ORCHIDEE-PEAT (revision 4596), a model for northern peatland CO2, water, and energy fluxes on daily to annual scales

Author

Qiu, Chunjing, Zhu, Dan, Ciais, Philippe, Guenet, Bertrand, Krinner, Gerhard, Peng, Shushi, Aurela, Mika, Bernhofer, Christian, Brümmer, Christian, Bret-Harte, Syndonia, Chu, Housen, Chen, Jiquan, Desai, Ankur R, Dušek, Jiří, Euskirchen, Eugénie S, Fortuniak, Krzysztof, Flanagan, Lawrence B, Friborg, Thomas, Grygoruk, Mateusz, Gogo, Sébastien, Grünwald, Thomas, Hansen, Birger U, Holl, David, Humphreys, Elyn, Hurkuck, Miriam, Kiely, Gerard, Klatt, Janina, Kutzbach, Lars, Largeron, Chloé, Laggoun-Défarge, Fatima, Lund, Magnus, Lafleur, Peter M, Li, Xuefei, Mammarella, Ivan, Merbold, Lutz, Nilsson, Mats B, Olejnik, Janusz, Ottosson-Löfvenius, Mikaell, Oechel, Walter, Parmentier, Frans-Jan W, Peichl, Matthias, Pirk, Norbert, Peltola, Olli, Pawlak, Włodzimierz, Rasse, Daniel, Rinne, Janne, Shaver, Gaius, Schmid, Hans Peter, Sottocornola, Matteo, Steinbrecher, Rainer, Sachs, Torsten, Urbaniak, Marek, Zona, Donatella, and Ziemblinska, Klaudia

Subjects
Earth Sciences, Atmospheric Sciences, Earth sciences
Abstract

Peatlands store substantial amounts of carbon and are vulnerable to climate change. We present a modified version of the Organising Carbon and Hydrology In Dynamic Ecosystems (ORCHIDEE) land surface model for simulating the hydrology, surface energy, and CO2 fluxes of peatlands on daily to annual timescales. The model includes a separate soil tile in each 0.5° grid cell, defined from a global peatland map and identified with peat-specific soil hydraulic properties. Runoff from non-peat vegetation within a grid cell containing a fraction of peat is routed to this peat soil tile, which maintains shallow water tables. The water table position separates oxic from anoxic decomposition. The model was evaluated against eddy-covariance (EC) observations from 30 northern peatland sites, with the maximum rate of carboxylation (Vcmax) being optimized at each site. Regarding short-term day-to-day variations, the model performance was good for gross primary production (GPP) (r2 Combining double low line 0.76; Nash-Sutcliffe modeling efficiency, MEF Combining double low line 0.76) and ecosystem respiration (ER, r2 Combining double low line 0.78, MEF Combining double low line 0.75), with lesser accuracy for latent heat fluxes (LE, r2 Combining double low line 0.42, MEF Combining double low line 0.14) and and net ecosystem CO2 exchange (NEE, r2 Combining double low line 0.38, MEF Combining double low line 0.26). Seasonal variations in GPP, ER, NEE, and energy fluxes on monthly scales showed moderate to high r2 values (0.57-0.86). For spatial across-site gradients of annual mean GPP, ER, NEE, and LE, r2 values of 0.93, 0.89, 0.27, and 0.71 were achieved, respectively. Water table (WT) variation was not well predicted (r2

Published
2018

9. Contributors

Author

Ahlström, Anders, primary, Almeida, Mariana, additional, Andrew, Robbie, additional, Archibeque, Shawn, additional, Basso, Luana, additional, Bastos, Ana, additional, Bezerra, Francisco Gilney, additional, Birdsey, Richard, additional, Bowman, Kevin, additional, Bruhwiler, Lori M., additional, Brunner, Dominik, additional, Bun, Rostyslav, additional, Butman, David E., additional, Campbell, Donovan, additional, Canadell, Josep G., additional, Cardoso, Manoel, additional, Chatterjee, Abhishek, additional, Chevallier, Frédéric, additional, Ciais, Philippe, additional, Commane, Róisín, additional, Crippa, Monica, additional, Cunha-Zeri, Gisleine, additional, Domke, Grant M., additional, Euskirchen, Eugénie S., additional, Fisher, Joshua B., additional, Gilfillan, Dennis, additional, Hayes, Daniel J., additional, Holmquist, James R., additional, Houghton, Richard A., additional, Huntzinger, Deborah, additional, Ilyina, Tatiana, additional, Janardanan, Rajesh, additional, Janssens-Maenhout, Greet, additional, Jones, Matthew W., additional, Keppler, Lydia, additional, Kondo, Masayuki, additional, Kroeger, Kevin D., additional, Kurz, Werner, additional, Landschützer, Peter, additional, Lauerwald, Ronny, additional, Luyssaert, Sebastiaan, additional, MacBean, Natasha, additional, Maksyutov, Shamil, additional, Marland, Eric, additional, Marland, Gregg, additional, Miranda, Marcela, additional, Naipal, Victoria, additional, Naudts, Kim, additional, Neigh, Christopher S.R., additional, Neto, Eráclito Souza, additional, Nevison, Cynthia, additional, Niu, Shuli, additional, Oda, Tomohiro, additional, Ogle, Stephen M., additional, Ometto, Jean Pierre, additional, Ott, Lesley, additional, Pacheco, Felipe S., additional, Parmentier, Frans-Jan W., additional, Patra, Prabir K., additional, Petrescu, A.M. Roxana, additional, Pongratz, Julia, additional, Poulter, Benjamin, additional, Pugh, Thomas A.M., additional, Ramaswami, Anu, additional, Raymond, Peter A., additional, Rezende, Luiz Felipe, additional, Ribeiro, Kelly, additional, Roten, Dustin, additional, Schädel, Christina, additional, Schuur, Edward A.G., additional, Sitch, Stephen, additional, Smith, Pete, additional, Smith, William Kolby, additional, Taboada, Miguel, additional, Thompson, Rona L., additional, Tong, Kangkang, additional, Troxler, Tiffany G., additional, Tubiello, Francesco N., additional, Turner, Alexander J., additional, Villalobos, Yohanna, additional, von Randow, Celso, additional, Watts, Jennifer, additional, Welp, Lisa R., additional, Windham-Myers, Lisamarie, additional, and Zavala-Araiza, Daniel, additional

Published
2022
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10. Variability and quasi-decadal changes in the methane budget over the period 2000–2012

Author

Saunois, Marielle, Bousquet, Philippe, Poulter, Ben, Peregon, Anna, Ciais, Philippe, Canadell, Josep G, Dlugokencky, Edward J, Etiope, Giuseppe, Bastviken, David, Houweling, Sander, Janssens-Maenhout, Greet, Tubiello, Francesco N, Castaldi, Simona, Jackson, Robert B, Alexe, Mihai, Arora, Vivek K, Beerling, David J, Bergamaschi, Peter, Blake, Donald R, Brailsford, Gordon, Bruhwiler, Lori, Crevoisier, Cyril, Crill, Patrick, Covey, Kristofer, Frankenberg, Christian, Gedney, Nicola, Höglund-Isaksson, Lena, Ishizawa, Misa, Ito, Akihiko, Joos, Fortunat, Kim, Heon-Sook, Kleinen, Thomas, Krummel, Paul, Lamarque, Jean-François, Langenfelds, Ray, Locatelli, Robin, Machida, Toshinobu, Maksyutov, Shamil, Melton, Joe R, Morino, Isamu, Naik, Vaishali, O'Doherty, Simon, Parmentier, Frans-Jan W, Patra, Prabir K, Peng, Changhui, Peng, Shushi, Peters, Glen P, Pison, Isabelle, Prinn, Ronald, Ramonet, Michel, Riley, William J, Saito, Makoto, Santini, Monia, Schroeder, Ronny, Simpson, Isobel J, Spahni, Renato, Takizawa, Atsushi, Thornton, Brett F, Tian, Hanqin, Tohjima, Yasunori, Viovy, Nicolas, Voulgarakis, Apostolos, Weiss, Ray, Wilton, David J, Wiltshire, Andy, Worthy, Doug, Wunch, Debra, Xu, Xiyan, Yoshida, Yukio, Zhang, Bowen, Zhang, Zhen, and Zhu, Qiuan

Subjects
Earth Sciences, Atmospheric Sciences, Climate Action, Astronomical and Space Sciences, Meteorology & Atmospheric Sciences, Atmospheric sciences, Climate change science
Abstract

Following the recent Global Carbon Project (GCP) synthesis of the decadal methane (CH4) budget over 2000-2012 (Saunois et al., 2016), we analyse here the same dataset with a focus on quasi-decadal and inter-annual variability in CH4 emissions. The GCP dataset integrates results from top-down studies (exploiting atmospheric observations within an atmospheric inverse-modelling framework) and bottom-up models (including process-based models for estimating land surface emissions and atmospheric chemistry), inventories of anthropogenic emissions, and data-driven approaches. The annual global methane emissions from top-down studies, which by construction match the observed methane growth rate within their uncertainties, all show an increase in total methane emissions over the period 2000-2012, but this increase is not linear over the 13 years. Despite differences between individual studies, the mean emission anomaly of the top-down ensemble shows no significant trend in total methane emissions over the period 2000-2006, during the plateau of atmospheric methane mole fractions, and also over the period 2008-2012, during the renewed atmospheric methane increase. However, the top-down ensemble mean produces an emission shift between 2006 and 2008, leading to 22 [16-32]Tg CH4yr-1 higher methane emissions over the period 2008-2012 compared to 2002-2006. This emission increase mostly originated from the tropics, with a smaller contribution from mid-latitudes and no significant change from boreal regions. The regional contributions remain uncertain in top-down studies. Tropical South America and South and East Asia seem to contribute the most to the emission increase in the tropics. However, these two regions have only limited atmospheric measurements and remain therefore poorly constrained. The sectorial partitioning of this emission increase between the periods 2002-2006 and 2008-2012 differs from one atmospheric inversion study to another. However, all top-down studies suggest smaller changes in fossil fuel emissions (from oil, gas, and coal industries) compared to the mean of the bottom-up inventories included in this study. This difference is partly driven by a smaller emission change in China from the top-down studies compared to the estimate in the Emission Database for Global Atmospheric Research (EDGARv4.2) inventory, which should be revised to smaller values in a near future. We apply isotopic signatures to the emission changes estimated for individual studies based on five emission sectors and find that for six individual top-down studies (out of eight) the average isotopic signature of the emission changes is not consistent with the observed change in atmospheric 13CH4. However, the partitioning in emission change derived from the ensemble mean is consistent with this isotopic constraint. At the global scale, the top-down ensemble mean suggests that the dominant contribution to the resumed atmospheric CH4 growth after 2006 comes from microbial sources (more from agriculture and waste sectors than from natural wetlands), with an uncertain but smaller contribution from fossil CH4 emissions. In addition, a decrease in biomass burning emissions (in agreement with the biomass burning emission databases) makes the balance of sources consistent with atmospheric 13CH4 observations. In most of the top-down studies included here, OH concentrations are considered constant over the years (seasonal variations but without any inter-annual variability). As a result, the methane loss (in particular through OH oxidation) varies mainly through the change in methane concentrations and not its oxidants. For these reasons, changes in the methane loss could not be properly investigated in this study, although it may play a significant role in the recent atmospheric methane changes as briefly discussed at the end of the paper.

Published
2017

11. Permafrost Carbon : Progress on Understanding Stocks and Fluxes Across Northern Terrestrial Ecosystems

Author

Treat, Claire C., Virkkala, Anna-Maria, Burke, Eleanor, Bruhwiler, Lori, Chatterjee, Abhishek, Fisher, Joshua B., Hashemi, Josh, Parmentier, Frans-Jan W., Rogers, Brendan M., Westermann, Sebastian, Watts, Jennifer D., Blanc-Betes, Elena, Fuchs, Matthias, Kruse, Stefan, Malhotra, Avni, Miner, Kimberley, Strauss, Jens, Armstrong, Amanda, Epstein, Howard E., Gay, Bradley, Goeckede, Mathias, Kalhori, Aram, Kou, Dan, Miller, Charles E., Natali, Susan M., Oh, Youmi, Shakil, Sarah, Sonnentag, Oliver, Varner, Ruth K., Zolkos, Scott, Schuur, Edward A. G., Hugelius, Gustaf, Treat, Claire C., Virkkala, Anna-Maria, Burke, Eleanor, Bruhwiler, Lori, Chatterjee, Abhishek, Fisher, Joshua B., Hashemi, Josh, Parmentier, Frans-Jan W., Rogers, Brendan M., Westermann, Sebastian, Watts, Jennifer D., Blanc-Betes, Elena, Fuchs, Matthias, Kruse, Stefan, Malhotra, Avni, Miner, Kimberley, Strauss, Jens, Armstrong, Amanda, Epstein, Howard E., Gay, Bradley, Goeckede, Mathias, Kalhori, Aram, Kou, Dan, Miller, Charles E., Natali, Susan M., Oh, Youmi, Shakil, Sarah, Sonnentag, Oliver, Varner, Ruth K., Zolkos, Scott, Schuur, Edward A. G., and Hugelius, Gustaf

Abstract

Significant progress in permafrost carbon science made over the past decades include the identification of vast permafrost carbon stocks, the development of new pan-Arctic permafrost maps, an increase in terrestrial measurement sites for CO2 and methane fluxes, and important factors affecting carbon cycling, including vegetation changes, periods of soil freezing and thawing, wildfire, and other disturbance events. Process-based modeling studies now include key elements of permafrost carbon cycling and advances in statistical modeling and inverse modeling enhance understanding of permafrost region C budgets. By combining existing data syntheses and model outputs, the permafrost region is likely a wetland methane source and small terrestrial ecosystem CO2 sink with lower net CO2 uptake toward higher latitudes, excluding wildfire emissions. For 2002–2014, the strongest CO2 sink was located in western Canada (median: −52 g C m−2 y−1) and smallest sinks in Alaska, Canadian tundra, and Siberian tundra (medians: −5 to −9 g C m−2 y−1). Eurasian regions had the largest median wetland methane fluxes (16–18 g CH4 m−2 y−1). Quantifying the regional scale carbon balance remains challenging because of high spatial and temporal variability and relatively low density of observations. More accurate permafrost region carbon fluxes require: (a) the development of better maps characterizing wetlands and dynamics of vegetation and disturbances, including abrupt permafrost thaw; (b) the establishment of new year-round CO2 and methane flux sites in underrepresented areas; and (c) improved models that better represent important permafrost carbon cycle dynamics, including non-growing season emissions and disturbance effects.

Published
2024
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13. The Global Methane Budget: 2000–2012

Author

Saunois, Marielle, Bousquet, Philippe, Poulter, Ben, Peregon, Anna, Ciais, Philippe, Canadell, Josep G, Dlugokencky, Edward J, Etiope, Giuseppe, Bastviken, David, Houweling, Sander, Janssens-Maenhout, Greet, Tubiello, Francesco N, Castaldi, Simona, Jackson, Robert B, Alexe, Mihai, Arora, Vivek K, Beerling, David J, Bergamaschi, Peter, Blake, Donald R, Brailsford, Gordon, Brovkin, Victor, Bruhwiler, Lori, Crevoisier, Cyril, Crill, Patrick, Curry, Charles, Frankenberg, Christian, Gedney, Nicola, Höglund-Isaksson, Lena, Ishizawa, Misa, Ito, Akihiko, Joos, Fortunat, Kim, Heon-Sook, Kleinen, Thomas, Krummel, Paul, Lamarque, Jean-François, Langenfelds, Ray, Locatelli, Robin, Machida, Toshinobu, Maksyutov, Shamil, McDonald, Kyle C, Marshall, Julia, Melton, Joe R, Morino, Isamu, O'Doherty, Simon, Parmentier, Frans-Jan W, Patra, Prabir K, Peng, Changhui, Peng, Shushi, Peters, Glen P, Pison, Isabelle, Prigent, Catherine, Prinn, Ronald, Ramonet, Michel, Riley, William J, Saito, Makoto, Schroeder, Ronny, Simpson, Isobel J, Spahni, Renato, Steele, Paul, Takizawa, Atsushi, Thornton, Brett F, Tian, Hanqin, Tohjima, Yasunori, Viovy, Nicolas, Voulgarakis, Apostolos, van Weele, Michiel, van der Werf, Guido, Weiss, Ray, Wiedinmyer, Christine, Wilton, David J, Wiltshire, Andy, Worthy, Doug, Wunch, Debra B, Xu, Xiyan, Yoshida, Yukio, Zhang, Bowen, Zhang, Zhen, and Zhu, Qiuan

Abstract

Abstract. The global methane (CH4) budget is becoming an increasingly important component for managing realistic pathways to mitigate climate change. This relevance, due to a shorter atmospheric lifetime and a stronger warming potential than carbon dioxide, is challenged by the still unexplained changes of atmospheric CH4 over the past decade. Emissions and concentrations of CH4 are continuing to increase making CH4 the second most important human-induced greenhouse gas after carbon dioxide. Two major difficulties in reducing uncertainties come from the large variety of diffusive CH4 sources that overlap geographically, and from the destruction of CH4 by the very short-lived hydroxyl radical (OH). To address these difficulties, we have established a consortium of multi-disciplinary scientists under the umbrella of the Global Carbon Project to synthesize and stimulate research on the methane cycle, and producing regular (~biennial) updates of the global methane budget. This consortium includes atmospheric physicists and chemists, biogeochemists of surface and marine emissions, and socio-economists who study anthropogenic emissions. Following Kirschke et al. (2013), we propose here the first version of a living review paper that integrates results of top-down studies (T-D, exploiting atmospheric observations within an atmospheric inverse-modelling framework) and bottom-up models, inventories, and data-driven approaches (B-U, including process-based models for estimating land surface emissions and atmospheric chemistry, and inventories for anthropogenic emissions, data-driven extrapolations). For the 2003–2012 decade, global methane emissions are estimated by T-D inversions at 558 Tg CH4 yr−1 (range [540–568]). About 60 % of global emissions are anthropogenic (range [50–65 %]). B-U approaches suggest larger global emissions (736 Tg CH4 yr−1 [596–884]) mostly because of larger natural emissions from individual sources such as inland waters, natural wetlands and geological sources. Considering the atmospheric constraints on the T-D budget, it is likely that some of the individual emissions reported by the B-U approaches are overestimated, leading to too large global emissions. Latitudinal data from T-D emissions indicate a predominance of tropical emissions (~64 % of the global budget,

Published
2016

14. Complexity revealed in the greening of the Arctic

Author

Myers-Smith, Isla H., Kerby, Jeffrey T., Phoenix, Gareth K., Bjerke, Jarle W., Epstein, Howard E., Assmann, Jakob J., John, Christian, Andreu-Hayles, Laia, Angers-Blondin, Sandra, Beck, Pieter S. A., Berner, Logan T., Bhatt, Uma S., Bjorkman, Anne D., Blok, Daan, Bryn, Anders, Christiansen, Casper T., Cornelissen, J. Hans C., Cunliffe, Andrew M., Elmendorf, Sarah C., Forbes, Bruce C., Goetz, Scott J., Hollister, Robert D., de Jong, Rogier, Loranty, Michael M., Macias-Fauria, Marc, Maseyk, Kadmiel, Normand, Signe, Olofsson, Johan, Parker, Thomas C., Parmentier, Frans-Jan W., Post, Eric, Schaepman-Strub, Gabriela, Stordal, Frode, Sullivan, Patrick F., Thomas, Haydn J. D., Tømmervik, Hans, Treharne, Rachael, Tweedie, Craig E., Walker, Donald A., Wilmking, Martin, and Wipf, Sonja

Published
2020
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15. The uncertain climate footprint of wetlands under human pressure

Author

Petrescu, Ana Maria Roxana, Lohila, Annalea, Tuovinen, Juha-Pekka, Baldocchi, Dennis D, Desai, Ankur R, Roulet, Nigel T, Vesala, Timo, Dolman, Albertus Johannes, Oechel, Walter C, Marcolla, Barbara, Friborg, Thomas, Rinne, Janne, Matthes, Jaclyn Hatala, Merbold, Lutz, Meijide, Ana, Kiely, Gerard, Sottocornola, Matteo, Sachs, Torsten, Zona, Donatella, Varlagin, Andrej, Lai, Derrick YF, Veenendaal, Elmar, Parmentier, Frans-Jan W, Skiba, Ute, Lund, Magnus, Hensen, Arjan, van Huissteden, Jacobus, Flanagan, Lawrence B, Shurpali, Narasinha J, Grünwald, Thomas, Humphreys, Elyn R, Jackowicz-Korczyński, Marcin, Aurela, Mika A, Laurila, Tuomas, Grüning, Carsten, Corradi, Chiara AR, Schrier-Uijl, Arina P, Christensen, Torben R, Tamstorf, Mikkel P, Mastepanov, Mikhail, Martikainen, Pertti J, Verma, Shashi B, Bernhofer, Christian, and Cescatti, Alessandro

Subjects
Climate Action, Life on Land, Carbon Dioxide, Climate, Climate Change, Ecology, Ecosystem, Geography, Human Activities, Humans, Methane, Models, Theoretical, Nitrous Oxide, Plants, Temperature, Uncertainty, Wetlands, wetland conversion, methane, radiative forcing, carbon dioxide
Abstract

Significant climate risks are associated with a positive carbon-temperature feedback in northern latitude carbon-rich ecosystems, making an accurate analysis of human impacts on the net greenhouse gas balance of wetlands a priority. Here, we provide a coherent assessment of the climate footprint of a network of wetland sites based on simultaneous and quasi-continuous ecosystem observations of CO2 and CH4 fluxes. Experimental areas are located both in natural and in managed wetlands and cover a wide range of climatic regions, ecosystem types, and management practices. Based on direct observations we predict that sustained CH4 emissions in natural ecosystems are in the long term (i.e., several centuries) typically offset by CO2 uptake, although with large spatiotemporal variability. Using a space-for-time analogy across ecological and climatic gradients, we represent the chronosequence from natural to managed conditions to quantify the "cost" of CH4 emissions for the benefit of net carbon sequestration. With a sustained pulse-response radiative forcing model, we found a significant increase in atmospheric forcing due to land management, in particular for wetland converted to cropland. Our results quantify the role of human activities on the climate footprint of northern wetlands and call for development of active mitigation strategies for managed wetlands and new guidelines of the Intergovernmental Panel on Climate Change (IPCC) accounting for both sustained CH4 emissions and cumulative CO2 exchange.

Published
2015

18. Climate–ecosystem modelling made easy: The Land Sites Platform

Author

Keetz, Lasse T., primary, Lieungh, Eva, additional, Karimi‐Asli, Kaveh, additional, Geange, Sonya R., additional, Gelati, Emiliano, additional, Tang, Hui, additional, Yilmaz, Yeliz A., additional, Aas, Kjetil S., additional, Althuizen, Inge H. J., additional, Bryn, Anders, additional, Falk, Stefanie, additional, Fisher, Rosie, additional, Fouilloux, Anne, additional, Horvath, Peter, additional, Indrehus, Sunniva, additional, Lee, Hanna, additional, Lombardozzi, Danica, additional, Parmentier, Frans‐Jan W., additional, Pirk, Norbert, additional, Vandvik, Vigdis, additional, Vollsnes, Ane V., additional, Skarpaas, Olav, additional, Stordal, Frode, additional, and Tallaksen, Lena M., additional

Published
2023
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21. Carbon uptake in Eurasian boreal forests dominates the high‐latitude net ecosystem carbon budget

Author

Watts, Jennifer D., primary, Farina, Mary, additional, Kimball, John S., additional, Schiferl, Luke D., additional, Liu, Zhihua, additional, Arndt, Kyle A., additional, Zona, Donatella, additional, Ballantyne, Ashley, additional, Euskirchen, Eugénie S., additional, Parmentier, Frans‐Jan W., additional, Helbig, Manuel, additional, Sonnentag, Oliver, additional, Tagesson, Torbern, additional, Rinne, Janne, additional, Ikawa, Hiroki, additional, Ueyama, Masahito, additional, Kobayashi, Hideki, additional, Sachs, Torsten, additional, Nadeau, Daniel F., additional, Kochendorfer, John, additional, Jackowicz‐Korczynski, Marcin, additional, Virkkala, Anna, additional, Aurela, Mika, additional, Commane, Roisin, additional, Byrne, Brendan, additional, Birch, Leah, additional, Johnson, Matthew S., additional, Madani, Nima, additional, Rogers, Brendan, additional, Du, Jinyang, additional, Endsley, Arthur, additional, Savage, Kathleen, additional, Poulter, Ben, additional, Zhang, Zhen, additional, Bruhwiler, Lori M., additional, Miller, Charles E., additional, Goetz, Scott, additional, and Oechel, Walter C., additional

Published
2023
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23. The Northernmost Hyperspectral Flox Sensor Dataset for Monitoring of High-Arctic Tundra Vegetation Phenology and Sun-Induced Fluorescence (SIF)

Author

Tommervik, Hans, primary, Julitta, Tommaso, additional, Nilsen, Lennart, additional, Park, Taejin, additional, Burkart, Andreas, additional, Ostopowic, Katarzyna, additional, Karlsen, Stein Rune, additional, Parmentier, Frans-Jan W., additional, Pirk, Norbert, additional, and Bjerke, Jarle W., additional

Published
2023
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25. Author Correction: Large loss of CO2 in winter observed across the northern permafrost region

Author

Natali, Susan M., Watts, Jennifer D., Rogers, Brendan M., Potter, Stefano, Ludwig, Sarah M., Selbmann, Anne-Katrin, Sullivan, Patrick F., Abbott, Benjamin W., Arndt, Kyle A., Birch, Leah, Björkman, Mats P., Bloom, A. Anthony, Celis, Gerardo, Christensen, Torben R., Christiansen, Casper T., Commane, Roisin, Cooper, Elisabeth J., Crill, Patrick, Czimczik, Claudia, Davydov, Sergey, Du, Jinyang, Egan, Jocelyn E., Elberling, Bo, Euskirchen, Eugenie S., Friborg, Thomas, Genet, Hélène, Göckede, Mathias, Goodrich, Jordan P., Grogan, Paul, Helbig, Manuel, Jafarov, Elchin E., Jastrow, Julie D., Kalhori, Aram A. M., Kim, Yongwon, Kimball, John S., Kutzbach, Lars, Lara, Mark J., Larsen, Klaus S., Lee, Bang-Yong, Liu, Zhihua, Loranty, Michael M., Lund, Magnus, Lupascu, Massimo, Madani, Nima, Malhotra, Avni, Matamala, Roser, McFarland, Jack, McGuire, A. David, Michelsen, Anders, Minions, Christina, Oechel, Walter C., Olefeldt, David, Parmentier, Frans-Jan W., Pirk, Norbert, Poulter, Ben, Quinton, William, Rezanezhad, Fereidoun, Risk, David, Sachs, Torsten, Schaefer, Kevin, Schmidt, Niels M., Schuur, Edward A. G., Semenchuk, Philipp R., Shaver, Gaius, Sonnentag, Oliver, Starr, Gregory, Treat, Claire C., Waldrop, Mark P., Wang, Yihui, Welker, Jeffrey, Wille, Christian, Xu, Xiaofeng, Zhang, Zhen, Zhuang, Qianlai, and Zona, Donatella

Published
2019
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27. The ABCflux database: Arctic–boreal CO2 flux observations and ancillary information aggregated to monthly time steps across terrestrial ecosystems

Author

Virkkala​​​​​​​, Anna-Maria, Natali, Susan M., Rogers, Brendan M., Watts, Jennifer D., Savage, Kathleen, Connon, Sara June, Mauritz, Marguerite, Schuur, Edward A. G., Peter, Darcy, Minions, Christina, Nojeim, Julia, Commane, Roisin, Emmerton, Craig A., Goeckede, Mathias, Helbig, Manuel, Holl, David, Iwata, Hiroki, Kobayashi, Hideki, Kolari, Pasi, López-Blanco, Efrén, Marushchak, Maija E., Mastepanov, Mikhail, Merbold, Lutz, Parmentier, Frans-Jan W., Peichl, Matthias, Sachs, Torsten, Sonnentag, Oliver, Ueyama, Masahito, Voigt, Carolina, Aurela, Mika, Boike, Julia, Celis, Gerardo, Chae, Namyi, Christensen, Torben R., Bret-Harte, M. Syndonia, Dengel, Sigrid, Dolman, Han, Edgar, Colin W., Elberling, Bo, Euskirchen, Eugenie, Grelle, Achim, Hatakka, Juha, Humphreys, Elyn, Järveoja, Järvi, Kotani, Ayumi, Kutzbach, Lars, Laurila, Tuomas, Lohila, Annalea, Mammarella, Ivan, Matsuura, Yojiro, Meyer, Gesa, Nilsson, Mats B., Oberbauer, Steven F., Park, Sang-Jong, Petrov, Roman, Prokushkin, Anatoly S., Schulze, Christopher, St. Louis, Vincent L., Tuittila, Eeva-Stiina, Tuovinen, Juha-Pekka, Quinton, William, Varlagin, Andrej, Zona, Donatella, Zyryanov, Viacheslav I., Virkkala​​​​​​​, Anna-Maria, Natali, Susan M., Rogers, Brendan M., Watts, Jennifer D., Savage, Kathleen, Connon, Sara June, Mauritz, Marguerite, Schuur, Edward A. G., Peter, Darcy, Minions, Christina, Nojeim, Julia, Commane, Roisin, Emmerton, Craig A., Goeckede, Mathias, Helbig, Manuel, Holl, David, Iwata, Hiroki, Kobayashi, Hideki, Kolari, Pasi, López-Blanco, Efrén, Marushchak, Maija E., Mastepanov, Mikhail, Merbold, Lutz, Parmentier, Frans-Jan W., Peichl, Matthias, Sachs, Torsten, Sonnentag, Oliver, Ueyama, Masahito, Voigt, Carolina, Aurela, Mika, Boike, Julia, Celis, Gerardo, Chae, Namyi, Christensen, Torben R., Bret-Harte, M. Syndonia, Dengel, Sigrid, Dolman, Han, Edgar, Colin W., Elberling, Bo, Euskirchen, Eugenie, Grelle, Achim, Hatakka, Juha, Humphreys, Elyn, Järveoja, Järvi, Kotani, Ayumi, Kutzbach, Lars, Laurila, Tuomas, Lohila, Annalea, Mammarella, Ivan, Matsuura, Yojiro, Meyer, Gesa, Nilsson, Mats B., Oberbauer, Steven F., Park, Sang-Jong, Petrov, Roman, Prokushkin, Anatoly S., Schulze, Christopher, St. Louis, Vincent L., Tuittila, Eeva-Stiina, Tuovinen, Juha-Pekka, Quinton, William, Varlagin, Andrej, Zona, Donatella, and Zyryanov, Viacheslav I.

Abstract

Past efforts to synthesize and quantify the magnitude and change in carbon dioxide (CO2) fluxes in terrestrial ecosystems across the rapidly warming Arctic–boreal zone (ABZ) have provided valuable information but were limited in their geographical and temporal coverage. Furthermore, these efforts have been based on data aggregated over varying time periods, often with only minimal site ancillary data, thus limiting their potential to be used in large-scale carbon budget assessments. To bridge these gaps, we developed a standardized monthly database of Arctic–boreal CO2 fluxes (ABCflux) that aggregates in situ measurements of terrestrial net ecosystem CO2 exchange and its derived partitioned component fluxes: gross primary productivity and ecosystem respiration. The data span from 1989 to 2020 with over 70 supporting variables that describe key site conditions (e.g., vegetation and disturbance type), micrometeorological and environmental measurements (e.g., air and soil temperatures), and flux measurement techniques. Here, we describe these variables, the spatial and temporal distribution of observations, the main strengths and limitations of the database, and the potential research opportunities it enables. In total, ABCflux includes 244 sites and 6309 monthly observations; 136 sites and 2217 monthly observations represent tundra, and 108 sites and 4092 observations represent the boreal biome. The database includes fluxes estimated with chamber (19 % of the monthly observations), snow diffusion (3 %) and eddy covariance (78 %) techniques. The largest number of observations were collected during the climatological summer (June–August; 32 %), and fewer observations were available for autumn (September–October; 25 %), winter (December–February; 18 %), and spring (March–May; 25 %). ABCflux can be used in a wide array of empirical, remote sensing and modeling studies to improve understanding of the regional and temporal variability in CO2 fluxes and to better estimate th

Published
2022

28. Vegetation type is an important predictor of the arctic summer land surface energy budget

Author

Environmental Sciences, Afd Marine and Atmospheric Research, Spatial Ecology and Global Change, Sub Algemeen Marine & Atmospheric Res, Oehri, Jacqueline, Schaepman-Strub, Gabriela, Kim, Jin-Soo, Grysko, Raleigh, Kropp, Heather, Grünberg, Inge, Zemlianskii, Vitalii, Sonnentag, Oliver, Euskirchen, Eugénie S., Reji Chacko, Merin, Muscari, Giovanni, Blanken, Peter D., Dean, Joshua F., di Sarra, Alcide, Harding, Richard J., Sobota, Ireneusz, Kutzbach, Lars, Plekhanova, Elena, Riihelä, Aku, Boike, Julia, Miller, Nathaniel B., Beringer, Jason, López-Blanco, Efrén, Stoy, Paul C., Sullivan, Ryan C., Kejna, Marek, Parmentier, Frans-Jan W., Gamon, John A., Mastepanov, Mikhail, Wille, Christian, Jackowicz-Korczynski, Marcin, Karger, Dirk N., Quinton, William L., Putkonen, Jaakko, van As, Dirk, Christensen, Torben R., Hakuba, Maria Z., Stone, Robert S., Metzger, Stefan, Vandecrux, Baptiste, Frost, Gerald V., Wild, Martin, Hansen, Birger, Meloni, Daniela, Domine, Florent, te Beest, Mariska, Sachs, Torsten, Kalhori, Aram, Rocha, Adrian V., Williamson, Scott N., Morris, Sara, Atchley, Adam L., Essery, Richard, Runkle, Benjamin R. K., Holl, David, Riihimaki, Laura D., Iwata, Hiroki, Schuur, Edward A. G., Cox, Christopher J., Grachev, Andrey A., McFadden, Joseph P., Fausto, Robert S., Göckede, Mathias, Ueyama, Masahito, Pirk, Norbert, de Boer, Gijs, Bret-Harte, M. Syndonia, Leppäranta, Matti, Steffen, Konrad, Friborg, Thomas, Ohmura, Atsumu, Edgar, Colin W., Olofsson, Johan, Chambers, Scott D., Environmental Sciences, Afd Marine and Atmospheric Research, Spatial Ecology and Global Change, Sub Algemeen Marine & Atmospheric Res, Oehri, Jacqueline, Schaepman-Strub, Gabriela, Kim, Jin-Soo, Grysko, Raleigh, Kropp, Heather, Grünberg, Inge, Zemlianskii, Vitalii, Sonnentag, Oliver, Euskirchen, Eugénie S., Reji Chacko, Merin, Muscari, Giovanni, Blanken, Peter D., Dean, Joshua F., di Sarra, Alcide, Harding, Richard J., Sobota, Ireneusz, Kutzbach, Lars, Plekhanova, Elena, Riihelä, Aku, Boike, Julia, Miller, Nathaniel B., Beringer, Jason, López-Blanco, Efrén, Stoy, Paul C., Sullivan, Ryan C., Kejna, Marek, Parmentier, Frans-Jan W., Gamon, John A., Mastepanov, Mikhail, Wille, Christian, Jackowicz-Korczynski, Marcin, Karger, Dirk N., Quinton, William L., Putkonen, Jaakko, van As, Dirk, Christensen, Torben R., Hakuba, Maria Z., Stone, Robert S., Metzger, Stefan, Vandecrux, Baptiste, Frost, Gerald V., Wild, Martin, Hansen, Birger, Meloni, Daniela, Domine, Florent, te Beest, Mariska, Sachs, Torsten, Kalhori, Aram, Rocha, Adrian V., Williamson, Scott N., Morris, Sara, Atchley, Adam L., Essery, Richard, Runkle, Benjamin R. K., Holl, David, Riihimaki, Laura D., Iwata, Hiroki, Schuur, Edward A. G., Cox, Christopher J., Grachev, Andrey A., McFadden, Joseph P., Fausto, Robert S., Göckede, Mathias, Ueyama, Masahito, Pirk, Norbert, de Boer, Gijs, Bret-Harte, M. Syndonia, Leppäranta, Matti, Steffen, Konrad, Friborg, Thomas, Ohmura, Atsumu, Edgar, Colin W., Olofsson, Johan, and Chambers, Scott D.

Published
2022

29. The ABCflux database:Arctic-boreal CO2flux observations and ancillary information aggregated to monthly time steps across terrestrial ecosystems

Author

Virkkala, Anna Maria, Natali, Susan M., Rogers, Brendan M., Watts, Jennifer D., Savage, Kathleen, Connon, Sara June, Mauritz, Marguerite, Schuur, Edward A.G., Peter, Darcy, Minions, Christina, Nojeim, Julia, Commane, Roisin, Emmerton, Craig A., Goeckede, Mathias, Helbig, Manuel, Holl, David, Iwata, Hiroki, Kobayashi, Hideki, Kolari, Pasi, López-Blanco, Efrén, Marushchak, Maija E., Mastepanov, Mikhail, Merbold, Lutz, Parmentier, Frans Jan W., Peichl, Matthias, Sachs, Torsten, Sonnentag, Oliver, Ueyama, Masahito, Voigt, Carolina, Aurela, Mika, Boike, Julia, Celis, Gerardo, Chae, Namyi, Christensen, Torben R., Bret-Harte, M. Syndonia, Dengel, Sigrid, Dolman, Han, Edgar, Colin W., Elberling, Bo, Euskirchen, Eugenie, Grelle, Achim, Hatakka, Juha, Humphreys, Elyn, Järveoja, Järvi, Kotani, Ayumi, Kutzbach, Lars, Laurila, Tuomas, Lohila, Annalea, Mammarella, Ivan, Matsuura, Yojiro, Meyer, Gesa, Nilsson, Mats B., Oberbauer, Steven F., Park, Sang Jong, Petrov, Roman, Prokushkin, Anatoly S., Schulze, Christopher, St. Louis, Vincent L., Tuittila, Eeva Stiina, Tuovinen, Juha Pekka, Quinton, William, Varlagin, Andrej, Zona, Donatella, Zyryanov, Viacheslav I., Virkkala, Anna Maria, Natali, Susan M., Rogers, Brendan M., Watts, Jennifer D., Savage, Kathleen, Connon, Sara June, Mauritz, Marguerite, Schuur, Edward A.G., Peter, Darcy, Minions, Christina, Nojeim, Julia, Commane, Roisin, Emmerton, Craig A., Goeckede, Mathias, Helbig, Manuel, Holl, David, Iwata, Hiroki, Kobayashi, Hideki, Kolari, Pasi, López-Blanco, Efrén, Marushchak, Maija E., Mastepanov, Mikhail, Merbold, Lutz, Parmentier, Frans Jan W., Peichl, Matthias, Sachs, Torsten, Sonnentag, Oliver, Ueyama, Masahito, Voigt, Carolina, Aurela, Mika, Boike, Julia, Celis, Gerardo, Chae, Namyi, Christensen, Torben R., Bret-Harte, M. Syndonia, Dengel, Sigrid, Dolman, Han, Edgar, Colin W., Elberling, Bo, Euskirchen, Eugenie, Grelle, Achim, Hatakka, Juha, Humphreys, Elyn, Järveoja, Järvi, Kotani, Ayumi, Kutzbach, Lars, Laurila, Tuomas, Lohila, Annalea, Mammarella, Ivan, Matsuura, Yojiro, Meyer, Gesa, Nilsson, Mats B., Oberbauer, Steven F., Park, Sang Jong, Petrov, Roman, Prokushkin, Anatoly S., Schulze, Christopher, St. Louis, Vincent L., Tuittila, Eeva Stiina, Tuovinen, Juha Pekka, Quinton, William, Varlagin, Andrej, Zona, Donatella, and Zyryanov, Viacheslav I.

Abstract

Past efforts to synthesize and quantify the magnitude and change in carbon dioxide (CO2) fluxes in terrestrial ecosystems across the rapidly warming Arctic-boreal zone (ABZ) have provided valuable information but were limited in their geographical and temporal coverage. Furthermore, these efforts have been based on data aggregated over varying time periods, often with only minimal site ancillary data, thus limiting their potential to be used in large-scale carbon budget assessments. To bridge these gaps, we developed a standardized monthly database of Arctic-boreal CO2 fluxes (ABCflux) that aggregates in situ measurements of terrestrial net ecosystem CO2 exchange and its derived partitioned component fluxes: gross primary productivity and ecosystem respiration. The data span from 1989 to 2020 with over 70 supporting variables that describe key site conditions (e.g., vegetation and disturbance type), micrometeorological and environmental measurements (e.g., air and soil temperatures), and flux measurement techniques. Here, we describe these variables, the spatial and temporal distribution of observations, the main strengths and limitations of the database, and the potential research opportunities it enables. In total, ABCflux includes 244 sites and 6309 monthly observations; 136 sites and 2217 monthly observations represent tundra, and 108 sites and 4092 observations represent the boreal biome. The database includes fluxes estimated with chamber (19% of the monthly observations), snow diffusion (3%) and eddy covariance (78%) techniques. The largest number of observations were collected during the climatological summer (June-August; 32%), and fewer observations were available for autumn (September-October; 25%), winter (December-February; 18%), and spring (March-May; 25%). ABCflux can be used in a wide array of empirical, remote sensing and modeling studies to improve understanding of the regional and temporal variability in CO2 fluxes and to better estimate the te

Published
2022

35. The Boreal–Arctic Wetland and Lake Dataset (BAWLD)

Author

Olefeldt, David, primary, Hovemyr, Mikael, additional, Kuhn, McKenzie A., additional, Bastviken, David, additional, Bohn, Theodore J., additional, Connolly, John, additional, Crill, Patrick, additional, Euskirchen, Eugénie S., additional, Finkelstein, Sarah A., additional, Genet, Hélène, additional, Grosse, Guido, additional, Harris, Lorna I., additional, Heffernan, Liam, additional, Helbig, Manuel, additional, Hugelius, Gustaf, additional, Hutchins, Ryan, additional, Juutinen, Sari, additional, Lara, Mark J., additional, Malhotra, Avni, additional, Manies, Kristen, additional, McGuire, A. David, additional, Natali, Susan M., additional, O'Donnell, Jonathan A., additional, Parmentier, Frans-Jan W., additional, Räsänen, Aleksi, additional, Schädel, Christina, additional, Sonnentag, Oliver, additional, Strack, Maria, additional, Tank, Suzanne E., additional, Treat, Claire, additional, Varner, Ruth K., additional, Virtanen, Tarmo, additional, Warren, Rebecca K., additional, and Watts, Jennifer D., additional

Published
2021
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36. Model simulations of arctic biogeochemistry and permafrost extent are highly sensitive to the implemented snow scheme in LPJ-GUESS

Author

Pongracz, Alexandra, Wårlind, David, Miller, Paul A., and Parmentier, Frans-Jan W.

Abstract

The Arctic is warming rapidly, especially in winter, which is causing large-scale reductions in snow cover. Snow is one of the main controls on soil thermodynamics, and changes in its thickness and extent affect both permafrost thaw and soil biogeochemistry. Since soil respiration during the cold season potentially offsets carbon uptake during the growing season, it is essential to achieve a realistic simulation of the effect of snow cover on soil conditions to more accurately project the direction of arctic carbon–climate feedbacks under continued winter warming. The Lund–Potsdam–Jena General Ecosystem Simulator (LPJ-GUESS) dynamic vegetation model has used – up until now – a single layer snow scheme, which underestimated the insulation effect of snow, leading to a cold bias in soil temperature. To address this shortcoming, we developed and integrated a dynamic, multi-layer snow scheme in LPJ-GUESS. The new snow scheme performs well in simulating the insulation of snow at hundreds of locations across Russia compared to observations. We show that improving this single physical factor enhanced simulations of permafrost extent compared to an advanced permafrost product, where the overestimation of permafrost cover decreased from 10 % to 5 % using the new snow scheme. Besides soil thermodynamics, the new snow scheme resulted in a doubled winter respiration and an overall higher vegetation carbon content. This study highlights the importance of a correct representation of snow in ecosystem models to project biogeochemical processes that govern climate feedbacks. The new dynamic snow scheme is an essential improvement in the simulation of cold season processes, which reduces the uncertainty of model projections. These developments contribute to a more realistic simulation of arctic carbon–climate feedbacks.

Published
2021

38. The ABCflux database: Arctic-Boreal CO2 flux observations and ancillary information aggregated to monthly time steps across terrestrial ecosystems

Author

Virkkala, Anna-Maria, primary, Natali, Susan M., additional, Rogers, Brendan M., additional, Watts, Jennifer D., additional, Savage, Kathleen, additional, Connon, Sara June, additional, Mauritz, Marguerite, additional, Schuur, Edward A. G., additional, Peter, Darcy, additional, Minions, Christina, additional, Nojeim, Julia, additional, Commane, Roisin, additional, Emmerton, Craig A., additional, Goeckede, Mathias, additional, Helbig, Manuel, additional, Holl, David, additional, Iwata, Hiroki, additional, Kobayashi, Hideki, additional, Kolari, Pasi, additional, López-Blanco, Efrén, additional, Marushchak, Maija E., additional, Mastepanov, Mikhail, additional, Merbold, Lutz, additional, Parmentier, Frans-Jan W., additional, Peichl, Matthias, additional, Sachs, Torsten, additional, Sonnentag, Oliver, additional, Ueyama, Masahito, additional, Voigt, Carolina, additional, Aurela, Mika, additional, Boike, Julia, additional, Celis, Gerardo, additional, Chae, Namyi, additional, Christensen, Torben R., additional, Bret-Harte, M. Syndonia, additional, Dengel, Sigrid, additional, Dolman, Han, additional, Edgar, Colin W., additional, Elberling, Bo, additional, Euskirchen, Eugenie, additional, Grelle, Achim, additional, Hatakka, Juha, additional, Humphreys, Elyn, additional, Järveoja, Järvi, additional, Kotani, Ayumi, additional, Kutzbach, Lars, additional, Laurila, Tuomas, additional, Lohila, Annalea, additional, Mammarella, Ivan, additional, Matsuura, Yojiro, additional, Meyer, Gesa, additional, Nilsson, Mats B., additional, Oberbauer, Steven F., additional, Park, Sang-Jong, additional, Petrov, Roman, additional, Prokushkin, Anatoly S., additional, Schulze, Christopher, additional, St.Louis, Vincent L., additional, Tuittila, Eeva-Stiina, additional, Tuovinen, Juha-Pekka, additional, Quinton, William, additional, Varlagin, Andrej, additional, Zona, Donatella, additional, and Zyryanov, Viacheslav I., additional

Published
2021
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39. Statistical upscaling of ecosystem CO 2 fluxes across the terrestrial tundra and boreal domain: Regional patterns and uncertainties

Author

Virkkala, Anna‐Maria, primary, Aalto, Juha, additional, Rogers, Brendan M., additional, Tagesson, Torbern, additional, Treat, Claire C., additional, Natali, Susan M., additional, Watts, Jennifer D., additional, Potter, Stefano, additional, Lehtonen, Aleksi, additional, Mauritz, Marguerite, additional, Schuur, Edward A. G., additional, Kochendorfer, John, additional, Zona, Donatella, additional, Oechel, Walter, additional, Kobayashi, Hideki, additional, Humphreys, Elyn, additional, Goeckede, Mathias, additional, Iwata, Hiroki, additional, Lafleur, Peter M., additional, Euskirchen, Eugenie S., additional, Bokhorst, Stef, additional, Marushchak, Maija, additional, Martikainen, Pertti J., additional, Elberling, Bo, additional, Voigt, Carolina, additional, Biasi, Christina, additional, Sonnentag, Oliver, additional, Parmentier, Frans‐Jan W., additional, Ueyama, Masahito, additional, Celis, Gerardo, additional, St.Louis, Vincent L., additional, Emmerton, Craig A., additional, Peichl, Matthias, additional, Chi, Jinshu, additional, Järveoja, Järvi, additional, Nilsson, Mats B., additional, Oberbauer, Steven F., additional, Torn, Margaret S., additional, Park, Sang‐Jong, additional, Dolman, Han, additional, Mammarella, Ivan, additional, Chae, Namyi, additional, Poyatos, Rafael, additional, López‐Blanco, Efrén, additional, Christensen, Torben Røjle, additional, Kwon, Min Jung, additional, Sachs, Torsten, additional, Holl, David, additional, and Luoto, Miska, additional

Published
2021
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43. Supplementary material to "The Boreal-Arctic Wetland and Lake Dataset (BAWLD)"

Author

Olefeldt, David, primary, Hovemyr, Mikael, additional, Kuhn, McKenzie A., additional, Bastviken, David, additional, Bohn, Theodore J., additional, Connolly, John, additional, Crill, Patrick, additional, Euskirchen, Eugénie S., additional, Finkelstein, Sarah A., additional, Genet, Hélène, additional, Grosse, Guido, additional, Harris, Lorna I., additional, Heffernan, Liam, additional, Helbig, Manuel, additional, Hugelius, Gustaf, additional, Hutchins, Ryan, additional, Juutinen, Sari, additional, Lara, Mark J., additional, Malhotra, Avni, additional, Manies, Kristen, additional, McGuire, A. David, additional, Natali, Susan M., additional, O'Donnell, Jonathan A., additional, Parmentier, Frans-Jan W., additional, Räsänen, Aleksi, additional, Schädel, Christina, additional, Sonnentag, Oliver, additional, Strack, Maria, additional, Tank, Suzanne, additional, Treat, Claire, additional, Varner, Ruth K., additional, Virtanen, Tarmo, additional, Warren, Rebecca K., additional, and Watts, Jennifer D., additional

Published
2021
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44. The Boreal–Arctic Wetland and Lake Dataset (BAWLD)

Author

Olefeldt, David, Hovemyr, Mikael, Kuhn, McKenzie A., Bastviken, David, Bohn, Theodore J., Connolly, John, Crill, Patrick, Euskirchen, Eugénie S., Finkelstein, Sarah A., Genet, Hélène, Grosse, Guido, Harris, Lorna I., Heffernan, Liam, Helbig, Manuel, Hugelius, Gustaf, Hutchins, Ryan, Juutinen, Sari, Lara, Mark J., Malhotra, Avni, Manies, Kristen, McGuire, A. David, Natali, Susan M., O'Donnell, Jonathan A., Parmentier, Frans-Jan W., Räsänen, Aleksi, Schädel, Christina, Sonnentag, Oliver, Strack, Maria, Tank, Suzanne E., Treat, Claire, Varner, Ruth K., Virtanen, Tarmo, Warren, Rebecca K., Watts, Jennifer D., Olefeldt, David, Hovemyr, Mikael, Kuhn, McKenzie A., Bastviken, David, Bohn, Theodore J., Connolly, John, Crill, Patrick, Euskirchen, Eugénie S., Finkelstein, Sarah A., Genet, Hélène, Grosse, Guido, Harris, Lorna I., Heffernan, Liam, Helbig, Manuel, Hugelius, Gustaf, Hutchins, Ryan, Juutinen, Sari, Lara, Mark J., Malhotra, Avni, Manies, Kristen, McGuire, A. David, Natali, Susan M., O'Donnell, Jonathan A., Parmentier, Frans-Jan W., Räsänen, Aleksi, Schädel, Christina, Sonnentag, Oliver, Strack, Maria, Tank, Suzanne E., Treat, Claire, Varner, Ruth K., Virtanen, Tarmo, Warren, Rebecca K., and Watts, Jennifer D.

Abstract

Methane emissions from boreal and arctic wetlands, lakes, and rivers are expected to increase in response to warming and associated permafrost thaw. However, the lack of appropriate land cover datasets for scaling field-measured methane emissions to circumpolar scales has contributed to a large uncertainty for our understanding of present-day and future methane emissions. Here we present the Boreal–Arctic Wetland and Lake Dataset (BAWLD), a land cover dataset based on an expert assessment, extrapolated using random forest modelling from available spatial datasets of climate, topography, soils, permafrost conditions, vegetation, wetlands, and surface water extents and dynamics. In BAWLD, we estimate the fractional coverage of five wetland, seven lake, and three river classes within 0.5 × 0.5∘ grid cells that cover the northern boreal and tundra biomes (17 % of the global land surface). Land cover classes were defined using criteria that ensured distinct methane emissions among classes, as indicated by a co-developed comprehensive dataset of methane flux observations. In BAWLD, wetlands occupied 3.2 × 106 km2 (14 % of domain) with a 95 % confidence interval between 2.8 and 3.8 × 106 km2. Bog, fen, and permafrost bog were the most abundant wetland classes, covering ∼ 28 % each of the total wetland area, while the highest-methane-emitting marsh and tundra wetland classes occupied 5 % and 12 %, respectively. Lakes, defined to include all lentic open-water ecosystems regardless of size, covered 1.4 × 106 km2 (6 % of domain). Low-methane-emitting large lakes (>10 km2) and glacial lakes jointly represented 78 % of the total lake area, while high-emitting peatland and yedoma lakes covered 18 % and 4 %, respectively. Small (<0.1 km2) glacial, peatland, and yedoma lakes combined covered 17 % of the total lake area but contributed disproportionally to the overall spatial uncertainty in lake area with a 95 % confidence interval between 0.15 and 0.38 × 106 km2. Rivers and streams

Published
2021

45. Statistical upscaling of ecosystem CO 2 fluxes across the terrestrial tundra and boreal domain: Regional patterns and uncertainties

Author

Virkkala, Anna‐Maria, Aalto, Juha, Rogers, Brendan M., Tagesson, Torbern, Treat, Claire C., Natali, Susan M., Watts, Jennifer D., Potter, Stefano, Lehtonen, Aleksi, Mauritz, Marguerite, Schuur, Edward A. G., Kochendorfer, John, Zona, Donatella, Oechel, Walter, Kobayashi, Hideki, Humphreys, Elyn, Goeckede, Mathias, Iwata, Hiroki, Lafleur, Peter M., Euskirchen, Eugenie S., Bokhorst, Stef, Marushchak, Maija, Martikainen, Pertti J., Elberling, Bo, Voigt, Carolina, Biasi, Christina, Sonnentag, Oliver, Parmentier, Frans‐Jan W., Ueyama, Masahito, Celis, Gerardo, St.Louis, Vincent L., Emmerton, Craig A., Peichl, Matthias, Chi, Jinshu, Järveoja, Järvi, Nilsson, Mats B., Oberbauer, Steven F., Torn, Margaret S., Park, Sang‐Jong, Dolman, Han, Mammarella, Ivan, Chae, Namyi, Poyatos, Rafael, López‐Blanco, Efrén, Christensen, Torben Røjle, Kwon, Min Jung, Sachs, Torsten, Holl, David, Luoto, Miska, Virkkala, Anna‐Maria, Aalto, Juha, Rogers, Brendan M., Tagesson, Torbern, Treat, Claire C., Natali, Susan M., Watts, Jennifer D., Potter, Stefano, Lehtonen, Aleksi, Mauritz, Marguerite, Schuur, Edward A. G., Kochendorfer, John, Zona, Donatella, Oechel, Walter, Kobayashi, Hideki, Humphreys, Elyn, Goeckede, Mathias, Iwata, Hiroki, Lafleur, Peter M., Euskirchen, Eugenie S., Bokhorst, Stef, Marushchak, Maija, Martikainen, Pertti J., Elberling, Bo, Voigt, Carolina, Biasi, Christina, Sonnentag, Oliver, Parmentier, Frans‐Jan W., Ueyama, Masahito, Celis, Gerardo, St.Louis, Vincent L., Emmerton, Craig A., Peichl, Matthias, Chi, Jinshu, Järveoja, Järvi, Nilsson, Mats B., Oberbauer, Steven F., Torn, Margaret S., Park, Sang‐Jong, Dolman, Han, Mammarella, Ivan, Chae, Namyi, Poyatos, Rafael, López‐Blanco, Efrén, Christensen, Torben Røjle, Kwon, Min Jung, Sachs, Torsten, Holl, David, and Luoto, Miska

Abstract

The regional variability in tundra and boreal carbon dioxide (CO2) fluxes can be high, complicating efforts to quantify sink-source patterns across the entire region. Statistical models are increasingly used to predict (i.e., upscale) CO2 fluxes across large spatial domains, but the reliability of different modeling techniques, each with different specifications and assumptions, has not been assessed in detail. Here, we compile eddy covariance and chamber measurements of annual and growing season CO2 fluxes of gross primary productivity (GPP), ecosystem respiration (ER), and net ecosystem exchange (NEE) during 1990–2015 from 148 terrestrial high-latitude (i.e., tundra and boreal) sites to analyze the spatial patterns and drivers of CO2 fluxes and test the accuracy and uncertainty of different statistical models. CO2 fluxes were upscaled at relatively high spatial resolution (1 km2) across the high-latitude region using five commonly used statistical models and their ensemble, that is, the median of all five models, using climatic, vegetation, and soil predictors. We found the performance of machine learning and ensemble predictions to outperform traditional regression methods. We also found the predictive performance of NEE-focused models to be low, relative to models predicting GPP and ER. Our data compilation and ensemble predictions showed that CO2 sink strength was larger in the boreal biome (observed and predicted average annual NEE −46 and −29 g C m−2 yr−1, respectively) compared to tundra (average annual NEE +10 and −2 g C m−2 yr−1). This pattern was associated with large spatial variability, reflecting local heterogeneity in soil organic carbon stocks, climate, and vegetation productivity. The terrestrial ecosystem CO2 budget, estimated using the annual NEE ensemble prediction, suggests the high-latitude region was on average an annual CO2 sink during 1990–2015, although uncertainty remains high.

Published
2021

46. Statistical upscaling of ecosystem CO2 fluxes across the terrestrial tundra and boreal domain: Regional patterns and uncertainties

Author

Virkkala, Anna‐Maria, Aalto, Juha, Rogers, Brendan M., Tagesson, Torbern, Treat, Claire C., Natali, Susan M., Watts, Jennifer D., Potter, Stefano, Lehtonen, Aleksi, Mauritz, Marguerite, Schuur, Edward A. G., Kochendorfer, John, Zona, Donatella, Oechel, Walter, Kobayashi, Hideki, Humphreys, Elyn, Goeckede, Mathias, Iwata, Hiroki, Lafleur, Peter M., Euskirchen, Eugenie S., Bokhorst, Stef, Marushchak, Maija, Martikainen, Pertti J., Elberling, Bo, Voigt, Carolina, Biasi, Christina, Sonnentag, Oliver, Parmentier, Frans‐Jan W., Ueyama, Masahito, Celis, Gerardo, St.Louis, Vincent L., Emmerton, Craig A., Peichl, Matthias, Chi, Jinshu, Järveoja, Järvi, Nilsson, Mats B., Oberbauer, Steven F., Torn, Margaret S., Park, Sang‐Jong, Dolman, Han, Mammarella, Ivan, Chae, Namyi, Poyatos, Rafael, López‐Blanco, Efrén, Christensen, Torben Røjle, Kwon, Min Jung, Sachs, Torsten, Holl, David, Luoto, Miska, Virkkala, Anna‐Maria, Aalto, Juha, Rogers, Brendan M., Tagesson, Torbern, Treat, Claire C., Natali, Susan M., Watts, Jennifer D., Potter, Stefano, Lehtonen, Aleksi, Mauritz, Marguerite, Schuur, Edward A. G., Kochendorfer, John, Zona, Donatella, Oechel, Walter, Kobayashi, Hideki, Humphreys, Elyn, Goeckede, Mathias, Iwata, Hiroki, Lafleur, Peter M., Euskirchen, Eugenie S., Bokhorst, Stef, Marushchak, Maija, Martikainen, Pertti J., Elberling, Bo, Voigt, Carolina, Biasi, Christina, Sonnentag, Oliver, Parmentier, Frans‐Jan W., Ueyama, Masahito, Celis, Gerardo, St.Louis, Vincent L., Emmerton, Craig A., Peichl, Matthias, Chi, Jinshu, Järveoja, Järvi, Nilsson, Mats B., Oberbauer, Steven F., Torn, Margaret S., Park, Sang‐Jong, Dolman, Han, Mammarella, Ivan, Chae, Namyi, Poyatos, Rafael, López‐Blanco, Efrén, Christensen, Torben Røjle, Kwon, Min Jung, Sachs, Torsten, Holl, David, and Luoto, Miska

Abstract

The regional variability in tundra and boreal carbon dioxide (CO2) fluxes can be high, complicating efforts to quantify sink-source patterns across the entire region. Statistical models are increasingly used to predict (i.e., upscale) CO2 fluxes across large spatial domains, but the reliability of different modeling techniques, each with different specifications and assumptions, has not been assessed in detail. Here, we compile eddy covariance and chamber measurements of annual and growing season CO2 fluxes of gross primary productivity (GPP), ecosystem respiration (ER), and net ecosystem exchange (NEE) during 1990–2015 from 148 terrestrial high-latitude (i.e., tundra and boreal) sites to analyze the spatial patterns and drivers of CO2 fluxes and test the accuracy and uncertainty of different statistical models. CO2 fluxes were upscaled at relatively high spatial resolution (1 km2) across the high-latitude region using five commonly used statistical models and their ensemble, that is, the median of all five models, using climatic, vegetation, and soil predictors. We found the performance of machine learning and ensemble predictions to outperform traditional regression methods. We also found the predictive performance of NEE-focused models to be low, relative to models predicting GPP and ER. Our data compilation and ensemble predictions showed that CO2 sink strength was larger in the boreal biome (observed and predicted average annual NEE −46 and −29 g C m −2 yr−1, respectively) compared to tundra (average annual NEE +10 and −2 g C m−2 yr−1). This pattern was associated with large spatial variability, reflecting local heterogeneity in soil organic carbon stocks, climate, and vegetation productivity. The terrestrial ecosystem CO2 budget, estimated using the annual NEE ensemble prediction, suggests the high-latitude region was on average a

Published
2021

47. Statistical upscaling of ecosystem CO2 fluxes across the terrestrial tundra and boreal domain:regional patterns and uncertainties

Author

Virkkala, Anna-Maria, Aalto, Juha, Rogers, Brendan M, Tagesson, Torbern, Treat, Claire C, Natali, Susan M, Watts, Jennifer D, Potter, Stefano, Lehtonen, Aleksi, Mauritz, Marguerite, Schuur, Edward A G, Kochendorfer, John, Zona, Donatella, Oechel, Walter, Kobayashi, Hideki, Humphreys, Elyn, Goeckede, Mathias, Iwata, Hiroki, Lafleur, Peter M, Euskirchen, Eugenie S, Bokhorst, Stef, Marushchak, Maija, Martikainen, Pertti J, Elberling, Bo, Voigt, Carolina, Biasi, Christina, Sonnentag, Oliver, Parmentier, Frans-Jan W, Ueyama, Masahito, Celis, Gerardo, St Loius, Vincent L, Emmerton, Craig A, Peichl, Matthias, Chi, Jinshu, Järveoja, Järvi, Nilsson, Mats B, Oberbauer, Steven F, Torn, Margaret S, Park, Sang-Jong, Dolman, Han, Mammarella, Ivan, Chae, Namyi, Poyatos, Rafael, López-Blanco, Efrén, Røjle Christensen, Torben, Jung Kwon, Min, Sachs, Torsten, Holl, David, Luoto, Miska, Virkkala, Anna-Maria, Aalto, Juha, Rogers, Brendan M, Tagesson, Torbern, Treat, Claire C, Natali, Susan M, Watts, Jennifer D, Potter, Stefano, Lehtonen, Aleksi, Mauritz, Marguerite, Schuur, Edward A G, Kochendorfer, John, Zona, Donatella, Oechel, Walter, Kobayashi, Hideki, Humphreys, Elyn, Goeckede, Mathias, Iwata, Hiroki, Lafleur, Peter M, Euskirchen, Eugenie S, Bokhorst, Stef, Marushchak, Maija, Martikainen, Pertti J, Elberling, Bo, Voigt, Carolina, Biasi, Christina, Sonnentag, Oliver, Parmentier, Frans-Jan W, Ueyama, Masahito, Celis, Gerardo, St Loius, Vincent L, Emmerton, Craig A, Peichl, Matthias, Chi, Jinshu, Järveoja, Järvi, Nilsson, Mats B, Oberbauer, Steven F, Torn, Margaret S, Park, Sang-Jong, Dolman, Han, Mammarella, Ivan, Chae, Namyi, Poyatos, Rafael, López-Blanco, Efrén, Røjle Christensen, Torben, Jung Kwon, Min, Sachs, Torsten, Holl, David, and Luoto, Miska

Abstract

The regional variability in tundra and boreal carbon dioxide (CO2 ) fluxes can be high, complicating efforts to quantify sink-source patterns across the entire region. Statistical models are increasingly used to predict (i.e., upscale) CO2 fluxes across large spatial domains, but the reliability of different modeling techniques, each with different specifications and assumptions, has not been assessed in detail. Here, we compile eddy covariance and chamber measurements of annual and growing season CO2 fluxes of gross primary productivity (GPP), ecosystem respiration (ER), and net ecosystem exchange (NEE) during 1990-2015 from 148 terrestrial high-latitude (i.e., tundra and boreal) sites to analyze the spatial patterns and drivers of CO2 fluxes and test the accuracy and uncertainty of different statistical models. CO2 fluxes were upscaled at relatively high spatial resolution (1 km2 ) across the high-latitude region using five commonly-used statistical models and their ensemble, i.e., the median of all five models, using climatic, vegetation, and soil predictors. We found the performance of machine learning and ensemble predictions to outperform traditional regression methods. We also found the predictive performance of NEE-focused models to be low, relative to models predicting GPP and ER. Our data compilation and ensemble predictions showed that CO2 sink strength was larger in the boreal biome (observed and predicted average annual NEE -46 and -29 g C m-2 yr-1 , respectively) compared to tundra (average annual NEE +10 and -2 g C m-2 yr-1 ). This pattern was associated with large spatial variability, reflecting local heterogeneity in soil organic carbon stocks, climate, and vegetation productivity. The terrestrial ecosystem CO2 budget, estimated using the annual NEE ensemble prediction, suggests the high-latitude region was on average an annual CO2 sink during 1990-2015, although uncertainty remains high.

Published
2021

48. Modeled microbial dynamics explain the apparent temperature-sensitivity of wetland methane emissions

Author

Chadburn, Sarah, Aalto, Tuula, Aurela, Mika, Baldocchi, Dennis, Biasi, Christina, Boike, Julia, Burke, Eleanor J., Comyn-Platt, Edward, Dolman, A. Johannes, Duran-Rojas, Carolina, Fan, Yuanchao, Friborg, Thomas, Gao, Yao, Gedney, Nicola, Göckede, Mathias, Hayman, Garry, D., Holl, David, Hugelius, Gustav, Kutzbach, Lars, Lee, Hanna, Lohila, Annalea, Parmentier, Frans-Jan W., Sachs, Torsten, Shurpali, Narasinha, and Westermann, Sebastian

Abstract

Methane emissions from natural wetlands tend to increase with temperature and therefore may lead to a positive feedback under future climate change. However, their temperature response includes confounding factors and appears to differ on different time scales. Observed methane emissions depend strongly on temperature on a seasonal basis, but if the annual mean emissions are compared between sites, there is only a small temperature effect. We hypothesize that microbial dynamics are a major driver of the seasonal cycle and that they can explain this apparent discrepancy. We introduce a relatively simple model of methanogenic growth and dormancy into a wetland methane scheme that is used in an Earth system model. We show that this addition is sufficient to reproduce the observed seasonal dynamics of methane emissions in fully saturated wetland sites, at the same time as reproducing the annual mean emissions. We find that a more complex scheme used in recent Earth system models does not add predictive power. The sites used span a range of climatic conditions, with the majority in high latitudes. The difference in apparent temperature sensitivity seasonally versus spatially cannot be recreated by the non‐microbial schemes tested. We therefore conclude that microbial dynamics are a strong candidate to be driving the seasonal cycle of wetland methane emissions. We quantify longer‐term temperature sensitivity using this scheme and show that it gives approximately a 12% increase in emissions per degree of warming globally. This is in addition to any hydrological changes, which could also impact future methane emissions.

Published
2020

49. Complexity revealed in the greening of the Arctic

Author

Myers-Smith, Isla H, Kerby, Jeffrey T, Phoenix, Gareth K, Bjerke, Jarle W, Epstein, Howard E, Assmann, Jakob J, John, Christian, Andreu-Hayles, Laia, Angers-Blondin, Sandra, Beck, Pieter S A, Berner, Logan T, Bhatt, Uma S, Bjorkman, Anne D, Blok, Daan, Bryn, Anders, Christiansen, Casper T, Cornelissen, J Hans C, Cunliffe, Andrew M, Elmendorf, Sarah C, Forbes, Bruce C, Goetz, Scott J, Hollister, Robert D, de Jong, Rogier, Loranty, Michael M, Macias-Fauria, Marc, Maseyk, Kadmiel, Normand, Signe, Olofsson, Johan, Parker, Thomas C, Parmentier, Frans-Jan W, Schaepman-Strub, Gabriela, et al, University of Zurich, and Myers-Smith, Isla H

Subjects
10127 Institute of Evolutionary Biology and Environmental Studies, 10122 Institute of Geography, UFSP13-8 Global Change and Biodiversity, 3301 Social Sciences (miscellaneous), 2301 Environmental Science (miscellaneous), 910 Geography & travel, Environmental Science (miscellaneous), Social Sciences (miscellaneous)
Published
2020

50. Modeled Microbial Dynamics Explain the Apparent Temperature Sensitivity of Wetland Methane Emissions

Author

Chadburn, Sarah E., Aalto, Tuula, Aurela, Mika, Baldocchi, Dennis, Biasi, Christina, Boike, Julia, Burke, Eleanor J., Comyn-Platt, Edward, Dolman, A. Johannes, Duran-Rojas, Carolina, Fan, Yuanchao, Friborg, Thomas, Gao, Yao, Gedney, Nicola, Göckede, Mathias, Hayman, Garry D., Holl, David, Hugelius, Gustaf, Kutzbach, Lars, Lee, Hanna, Lohila, Annalea, Parmentier, Frans-Jan W., Sachs, Torsten, Shurpali, Narasinha J., Westermann, Sebastian, Chadburn, Sarah E., Aalto, Tuula, Aurela, Mika, Baldocchi, Dennis, Biasi, Christina, Boike, Julia, Burke, Eleanor J., Comyn-Platt, Edward, Dolman, A. Johannes, Duran-Rojas, Carolina, Fan, Yuanchao, Friborg, Thomas, Gao, Yao, Gedney, Nicola, Göckede, Mathias, Hayman, Garry D., Holl, David, Hugelius, Gustaf, Kutzbach, Lars, Lee, Hanna, Lohila, Annalea, Parmentier, Frans-Jan W., Sachs, Torsten, Shurpali, Narasinha J., and Westermann, Sebastian

Abstract

Methane emissions from natural wetlands tend to increase with temperature and therefore may lead to a positive feedback under future climate change. However, their temperature response includes confounding factors and appears to differ on different time scales. Observed methane emissions depend strongly on temperature on a seasonal basis, but if the annual mean emissions are compared between sites, there is only a small temperature effect. We hypothesize that microbial dynamics are a major driver of the seasonal cycle and that they can explain this apparent discrepancy. We introduce a relatively simple model of methanogenic growth and dormancy into a wetland methane scheme that is used in an Earth system model. We show that this addition is sufficient to reproduce the observed seasonal dynamics of methane emissions in fully saturated wetland sites, at the same time as reproducing the annual mean emissions. We find that a more complex scheme used in recent Earth system models does not add predictive power. The sites used span a range of climatic conditions, with the majority in high latitudes. The difference in apparent temperature sensitivity seasonally versus spatially cannot be recreated by the non-microbial schemes tested. We therefore conclude that microbial dynamics are a strong candidate to be driving the seasonal cycle of wetland methane emissions. We quantify longer-term temperature sensitivity using this scheme and show that it gives approximately a 12% increase in emissions per degree of warming globally. This is in addition to any hydrological changes, which could also impact future methane emissions.

Published
2020
Full Text
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