Soil respiration-driven CO2 pulses dominate Australia?s flux variability

• 成果类型: Article
• 署名作者: Metz, Eva-Marie; Vardag, Sanam N.; Basu, Sourish; Jung, Martin; Ahrens, Bernhard; El-Madany, Tarek; Sitch, Stephen; Arora, Vivek K.; Briggs, Peter R.; Friedlingstein, Pierre; Goll, Daniel S.; Jain, Atul K.; Kato, Etsushi; Lombardozzi, Danica; Nabel, Julia E. M. S.; Poulter, Benjamin; Seferian, Roland; Tian, Hanqin; Wiltshire, Andrew; Yuan, Wenping; Yue, Xu; Zaehle, Soenke; Deutscher, Nicholas M.; Griffith, David W. T.; Butz, Andre
• 署名单位: Ruprecht Karls University Heidelberg; Ruprecht Karls University Heidelberg; National Aeronautics & Space Administration (NASA); NASA Goddard Space Flight Center; University System of Maryland; University of Maryland College Park; Max Planck Society; University of Exeter; Environment & Climate Change Canada; Canadian Centre for Climate Modelling & Analysis (CCCma); Commonwealth Scientific & Industrial Research Organisation (CSIRO); CSIRO Oceans & Atmosphere; University of Exeter; Institut Polytechnique de Paris; Ecole Polytechnique; Universite Paris Saclay; Universite PSL; Ecole Normale Superieure (ENS); Centre National de la Recherche Scientifique (CNRS); CNRS - National Institute for Earth Sciences & Astronomy (INSU); Sorbonne Universite; Universite Paris Saclay; Universite Paris Cite; CEA; Centre National de la Recherche Scientifique (CNRS); University of Illinois System; University of Illinois Urbana-Champaign; National Center Atmospheric Research (NCAR) - USA; Max Planck Society; National Aeronautics & Space Administration (NASA); NASA Goddard Space Flight Center; Centre National de la Recherche Scientifique (CNRS); Universite de Toulouse; Boston College; Met Office - UK; Hadley Centre; Southern Marine Science & Engineering Guangdong Laboratory; Southern Marine Science & Engineering Guangdong Laboratory (Zhuhai); Sun Yat Sen University; Nanjing University of Information Science & Technology; University of Wollongong; Ruprecht Karls University Heidelberg
• 刊物名称: SCIENCE
• ISSN/ISSBN: 0036-8849
• DOI: 10.1126/science.add7833
• 发表日期: 2023-03-31
• 页码: 1332-1335
• 关键词: semiarid ecosystems; carbon-dioxide; interannual variability; cycle; drought; assimilation; responses; sites

摘要

The Australian continent contributes substantially to the year-to-year variability of the global terrestrial carbon dioxide (CO2) sink. However, the scarcity of in situ observations in remote areas prevents the deciphering of processes that force the CO2 flux variability. In this study, by examining atmospheric CO2 measurements from satellites in the period 2009-2018, we find recurrent end-of-dry-season CO2 pulses over the Australian continent. These pulses largely control the year-to-year variability of Australia's CO2 balance. They cause two to three times larger seasonal variations compared with previous top-down inversions and bottom-up estimates. The pulses occur shortly after the onset of rainfall and are driven by enhanced soil respiration preceding photosynthetic uptake in Australia's semiarid regions. The suggested continental-scale relevance of soil-rewetting processes has substantial implications for our understanding and modeling of global climate-carbon cycle feedbacks.