Dominant regions and drivers of the variability of the global land carbon sink across timescales |
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Authors: | Xuanze Zhang Ying‐Ping Wang Shushi Peng Peter J Rayner Philippe Ciais Jeremy D Silver Shilong Piao Zaichun Zhu Xingjie Lu Xiaogu Zheng |
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Institution: | 1. Sino‐French Institute for Earth System Science, College of Urban and Environmental Sciences, Peking University, Beijing, China;2. South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, China;3. CSIRO Oceans and Atmosphere, Aspendale, VIC, Australia;4. School of Earth Sciences, University of Melbourne, Melbourne, VIC, Australia;5. Laboratoire des Sciences du Climat et de l'Environnement, LSCE/IPSL, CEA‐CNRS‐UVSQ, Université Paris‐Saclay, Gif‐sur‐Yvette, France;6. Key Laboratory of Alpine Ecology and Biodiversity, Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing, China;7. Center for Excellence in Tibetan Plateau Earth Science, Chinese Academy of Sciences, Beijing, China;8. Department of Botany and Microbiology, University of Oklahoma, Norman, Oklahoma;9. Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing, China |
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Abstract: | Net biome productivity (NBP) dominates the observed large variation of atmospheric CO2 annual increase over the last five decades. However, the dominant regions controlling inter‐annual to multi‐decadal variability of global NBP are still controversial (semi‐arid regions vs. temperate or tropical forests). By developing a theory for partitioning the variance of NBP into the contributions of net primary production (NPP) and heterotrophic respiration (Rh) at different timescales, and using both observation‐based atmospheric CO2 inversion product and the outputs of 10 process‐based terrestrial ecosystem models forced by 110‐year observational climate, we tried to reconcile the controversy by showing that semi‐arid lands dominate the variability of global NBP at inter‐annual (<10 years) and tropical forests dominate at multi‐decadal scales (>30 years). Results further indicate that global NBP variability is dominated by the NPP component at inter‐annual timescales, and is progressively controlled by Rh with increasing timescale. Multi‐decadal NBP variations of tropical rainforests are modulated by the Pacific Decadal Oscillation (PDO) through its significant influences on both temperature and precipitation. This study calls for long‐term observations for the decadal or longer fluctuations in carbon fluxes to gain insights on the future evolution of global NBP, particularly in the tropical forests that dominate the decadal variability of land carbon uptake and are more effective for climate mitigation. |
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Keywords: |
DGVM
ENSO
global carbon cycle land carbon sink PDO variability |
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