Regional atmospheric CO2 inversion reveals seasonal and geographic differences in Amazon net biome exchange |
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| Authors: | Caroline B Alden John B Miller Luciana V Gatti Manuel M Gloor Kaiyu Guan Anna M Michalak Ingrid T van der Laan‐Luijkx Danielle Touma Arlyn Andrews Luana S Basso Caio S C Correia Lucas G Domingues Joanna Joiner Maarten C Krol Alexei I Lyapustin Wouter Peters Yoichi P Shiga Kirk Thoning Ivar R van der Velde Thijs T van Leeuwen Vineet Yadav Noah S Diffenbaugh |
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| Institution: | 1. Department of Earth System Science, Stanford University, Stanford, CA, USA;2. Woods Institute for the Environment, Stanford University, Stanford, CA, USA;3. Global Monitoring Division, Earth System Research Laboratory, National Oceanic and Atmospheric Administration, Boulder, CO, USA;4. Cooperative Institute for Research in Environmental Sciences (CIRES), University of Colorado, Boulder, CO, USA;5. Instituto de Pesquisas Energéticas e Nucleares (IPEN)‐Comissao Nacional de Energia Nuclear (CNEN)‐Atmospheric Chemistry Laboratory, Sao Paulo, Brazil;6. School of Geography, University of Leeds, Leeds, UK;7. Department of Global Ecology, Carnegie Institution for Science, Stanford, CA, USA;8. Department of Meteorology and Air Quality, Wageningen University, Wageningen, The Netherlands;9. National Aeronautics and Space Administration, Goddard Space Flight Center, Greenbelt, MD, USA;10. Institute for Marine and Atmospheric Research Utrecht, Utrecht University, Utrecht, The Netherlands;11. SRON Netherlands Institute for Space Research, Utrecht, The Netherlands;12. University of Groningen, Centre for Isotope Research, Groningen, The Netherlands;13. Department of Civil and Environmental Engineering, Stanford University, Stanford, CA, USA;14. Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA |
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| Abstract: | Understanding tropical rainforest carbon exchange and its response to heat and drought is critical for quantifying the effects of climate change on tropical ecosystems, including global climate–carbon feedbacks. Of particular importance for the global carbon budget is net biome exchange of CO2 with the atmosphere (NBE), which represents nonfire carbon fluxes into and out of biomass and soils. Subannual and sub‐Basin Amazon NBE estimates have relied heavily on process‐based biosphere models, despite lack of model agreement with plot‐scale observations. We present a new analysis of airborne measurements that reveals monthly, regional‐scale (~1–8 × 106 km2) NBE variations. We develop a regional atmospheric CO2 inversion that provides the first analysis of geographic and temporal variability in Amazon biosphere–atmosphere carbon exchange and that is minimally influenced by biosphere model‐based first guesses of seasonal and annual mean fluxes. We find little evidence for a clear seasonal cycle in Amazon NBE but do find NBE sensitivity to aberrations from long‐term mean climate. In particular, we observe increased NBE (more carbon emitted to the atmosphere) associated with heat and drought in 2010, and correlations between wet season NBE and precipitation (negative correlation) and temperature (positive correlation). In the eastern Amazon, pulses of increased NBE persisted through 2011, suggesting legacy effects of 2010 heat and drought. We also identify regional differences in postdrought NBE that appear related to long‐term water availability. We examine satellite proxies and find evidence for higher gross primary productivity (GPP) during a pulse of increased carbon uptake in 2011, and lower GPP during a period of increased NBE in the 2010 dry season drought, but links between GPP and NBE changes are not conclusive. These results provide novel evidence of NBE sensitivity to short‐term temperature and moisture extremes in the Amazon, where monthly and sub‐Basin estimates have not been previously available. |
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| Keywords: | Amazon climate extremes
CO
2
inverse model terrestrial biosphere tropical carbon exchange |
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