B067-07
Estimating the Terrestrial Ecosystem CO2 Flux Budget for the Arctic-boreal Zone Using a Synthesis of Field Observations and Statistical Upscaling

Friday, 11 December 2020: 05:54
Virtual
Brendan M Rogers1, Anna-Maria Virkkala2, Susan Natali1, Jennifer Watts1, Kathleen E Savage1, Sara June Giacomini1, Christina Minions2, Darcy L. Peter2, Stefano Potter1, Marguerite Mauritz3, Julia Boike4, Gerardo Celis5,6, Roisin Commane7, Sigrid Dengel8, Eugenie Susanne Euskirchen9, Mathias Goeckede10, Yoshinobu Harazono11, Manuel Helbig12, Elyn Humphreys13, Hideki Kobayashi14, Min Jung Kwon15, Ayumi Kotani16, Takashi Machimura17, Steven F Oberbauer18, Sang-Jong Park19, Frans-Jan W Parmentier20, Mark Schildhauer21, Oliver Sonnentag22, Margaret S Torn23, Masahito Ueyama24 and Edward Schuur25, (1)Woods Hole Research Center, Falmouth, MA, United States, (2)Woods Hole Research Center, Falmouth, United States, (3)University of Texas at El Paso, El Paso, TX, United States, (4)Alfred Wegener Institute Helmholtz-Center for Polar and Marine Research Potsdam, Permafrost Research, Potsdam, Germany, (5)University of Florida, Ft Walton Beach, FL, United States, (6)Northern Arizona University, Center for Ecosystem Science and Society, Flagstaff, United States, (7)Columbia University in the City of New York, New York, NY, United States, (8)University of Helsinki, Helsinki, Finland, (9)University of Alaska Fairbanks, Fairbanks, AK, United States, (10)Max Planck Institute for Biogeochemistry, Jena, Germany, (11)Osaka Prefecture University, Graduate School of Life and Environmental Sciences, Sakai, Japan, (12)Dalhousie University, Department of Physics and Atmospheric Science, Halifax, NS, Canada, (13)Carleton University, Department of Geography and Environmental Studies, Ottawa, ON, Canada, (14)Japan Agency for Marine-Earth Science and Technology, Yokohama, Japan, (15)Korea Polar Research Institute, Incheon, South Korea, (16)Nagoya University, Graduate School of Bioagricultural Sciences, Nagoya, Japan, (17)Osaka University, Osaka, Japan, (18)Florida Intl Univ, Miami, FL, United States, (19)Korea Polar Research Institute, Division of Climate Change, Incheon, South Korea, (20)Arctic Research Centre, Aarhus University, Aarhus, Denmark, (21)National Center for Ecological Analysis and Synthesis, Santa Barbara, United States, (22)Université de Montréal, Département de Géographie, Montréal, QC, Canada, (23)Berkeley Lab/UC Berkeley, Berkeley, CA, United States, (24)Graduate School of Life and Environmental Sciences, Osaka Prefecture University, Sakai, Japan, (25)Northern Arizona University, Center for Ecosystem Science and Society, Flagstaff, AZ, United States
Recorded Presentation
Abstract:
The Arctic-boreal zone (ABZ) has been experiencing rapid warming that leads to both increased carbon dioxide (CO2) uptake from photosynthesis and release from respiration. The current balance between these two processes and how they have changed over time remains unresolved. Here we aim to estimate the terrestrial net ecosystem CO2 budget for the ABZ during 1980-2020. Using CO2 flux repositories, published literature, and community input, we developed a new database of monthly CO2 flux measurements of gross primary productivity (GPP), ecosystem respiration (ER), and net ecosystem exchange (NEE) from >100 eddy covariance and >40 chamber sites across the ABZ spanning 1989 to 2019. Monthly average growing season (GS, May-September) and non-growing season (NGS, October-April) NEE measurements multiplied by the number of GS and NGS months (5 and 7, respectively) resulted in a net ecosystem CO2 sink: average observed GS net uptake (boreal -119 g C m-2 GS-1 and tundra -90.9 g C m-2 GS-1; negative values indicating a sink) exceeded the NGS emissions (boreal 65.9 g C m-2 NGS-1 and tundra 72.4 g C m-2 NGS-1). Regional differences in NEE within the biomes were high, but the Alaskan and Canadian tundra were the only regions where NGS emissions exceeded GS uptake, suggesting these regions were annual CO2 sources. To provide budget estimates that are representative of the entire region, we plan to link these observations with geospatial products (e.g. remote sensing-derived indices, climate and soil variables) and upscale fluxes across the ABZ using an ensemble of machine learning models at monthly time steps from 1980 to 2020 at 1-km resolution. These NEE data products will be combined with estimates of disturbance and transport of carbon into the hydrosphere to provide an improved full ecosystem CO2 budget across the terrestrial ABZ, increasing our understanding of the role of ABZ for the global carbon budget.
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