1. Definitions and methods to estimate regional land carbon fluxes for the second phase of the REgional Carbon Cycle Assessment and Processes Project (RECCAP-2)
- Author
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Gustaf Hugelius, Benjamin Poulter, Chunjing Qiu, Ana Bastos, Ingrid T. Luijkx, Atul K. Jain, Hui Yang, Ronny Lauerwald, Pierre Regnier, Philippe Ciais, Wouter Peters, Marielle Saunois, Frédéric Chevallier, Anatoli Shvidenko, Celso von Randow, Masayuki Kondo, Hanqin Tian, Robert J. Scholes, Julia Pongratz, Bo Zheng, Prabir K. Patra, Shilong Piao, Xuhui Wang, Roxana Petrescu, Robert B. Jackson, Pep Canadell, Matthew W. Jones, Isotope Research, Earth and Climate, Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette] (LSCE), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), ICOS-ATC (ICOS-ATC), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Max-Planck-Institut für Biogeochemie (MPI-BGC), Modélisation INVerse pour les mesures atmosphériques et SATellitaires (SATINV), Agence Nationale de la Recherche, ANR, Cambridge Conservation Initiative, CCI, CLAND Convergence Institute, and Acknowledgements. Philippe Ciais acknowledges funding from the ANR CLAND Convergence Institute. Ana Bastos, Frédéric Cheval-lier, and Philippe Ciais acknowledge support from the VERIFY H2020 project and the RECCAP2 ESA Climate Change Initiative (CCI) project. The authors are very grateful to the many data providers (measurements, models, inventories, atmospheric inversions, hybrid products, etc.) that are directly or indirectly used in this study.
- Subjects
[SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere ,Carbon dioxide in Earth's atmosphere ,QE1-996.5 ,WIMEK ,Carbon accounting ,Land use ,chemistry.chemical_element ,Inversion (meteorology) ,Geology ,Luchtkwaliteit ,Atmospheric sciences ,Carbon cycle ,Air Quality ,chemistry ,Carbon project ,SDG 13 - Climate Action ,Life Science ,Environmental science ,Carbon ,Downscaling - Abstract
Regional land carbon budgets provide insights into the spatial distribution of the land uptake of atmospheric carbon dioxide and can be used to evaluate carbon cycle models and to define baselines for land-based additional mitigation efforts. The scientific community has been involved in providing observation-based estimates of regional carbon budgets either by downscaling atmospheric CO2 observations into surface fluxes with atmospheric inversions, by using inventories of carbon stock changes in terrestrial ecosystems, by upscaling local field observations such as flux towers with gridded climate and remote sensing fields, or by integrating data-driven or process-oriented terrestrial carbon cycle models. The first coordinated attempt to collect regional carbon budgets for nine regions covering the entire globe in the RECCAP-1 project has delivered estimates for the decade 2000–2009, but these budgets were not comparable between regions due to different definitions and component fluxes being reported or omitted. The recent recognition of lateral fluxes of carbon by human activities and rivers that connect CO2 uptake in one area with its release in another also requires better definitions and protocols to reach harmonized regional budgets that can be summed up to a globe scale and compared with the atmospheric CO2 growth rate and inversion results. In this study, using the international initiative RECCAP-2 coordinated by the Global Carbon Project, which aims to be an update to regional carbon budgets over the last 2 decades based on observations for 10 regions covering the globe with a better harmonization than the precursor project, we provide recommendations for using atmospheric inversion results to match bottom-up carbon accounting and models, and we define the different component fluxes of the net land atmosphere carbon exchange that should be reported by each research group in charge of each region. Special attention is given to lateral fluxes, inland water fluxes, and land use fluxes.
- Published
- 2022
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