Changing sensitivity of carbon exchange to atmospheric and soil moisture controls the response and recovery of carbon stocks in tropical South America from the 2015-2016 El Niño

Junjie Liu,  JPL,  junjie.liu@jpl.nasa.gov (Presenter)
Kevin W Bowman,  JPL,  kevin.bowman@jpl.nasa.gov
Paul Palmer,  University of Edinburgh,  pip@ed.ac.uk
Joanna Joiner,  NASA GSFC,  joanna.joiner@nasa.gov
Paul Levine,  JPL,  paul.a.levine@jpl.nasa.gov
Alexis Anthony Bloom,  JPL,  abloom@jpl.nasa.gov
Liang Feng,  University of Edinburgh,  liang.feng@ed.ac.uk
Sassan Saatchi,  Jet Propulsion Laboratory / Caltech,  saatchi@jpl.nasa.gov
Michael Keller,  USDA Forest Service,  mkeller.co2@gmail.com
Marcos Longo,  Jet Propulsion Laboratory,  mdplongo@gmail.com
Alex Konings,  Stanford University,  konings@stanford.edu
David Schimel,  JPL,  david.schimel@jpl.nasa.gov
Paul Wennberg,  Caltech,  wennberg@gps.caltech.edu

Tropical South America (SA) is projected to become drier in both air and soil by the late of this century. Thus, understanding how the terrestrial biosphere carbon cycle responds to drought events and its recovery and the possible interactive effects between air aridity and soil moisture drought are critical to predict its changes under future drier climate. In this study, we analyze the responses and recoveries of terrestrial biosphere carbon cycle over three subregions, west Amazon, northeast Amazon, and savanna/shrubland, from the drought caused by the 2015-2016 El Niño event. We use multiple net biosphere exchange products from top-down inversions inferred from GOSAT and OCO-2, and other satellite products that quantify component fluxes including gross primary production and biomass burning. We find a regionally dependent fast release of carbon during drought and slow recovery afterwards, linked to stage-dependent sensitivity to air aridity and the interactive effect of air aridity and water storage anomaly. The total carbon pools of the tropical SA had not recovered by the end of 2018, though carbon fluxes had recovered. Our study implies that only considering the sensitivity to air aridity and extrapolation to the future climate would underestimate the possible changes of photosynthesis and net carbon uptake. Moreover, tropical SA may become a source of carbon to the atmosphere instead of the current net carbon neutral state as it becomes drier in the future.

Poster: Poster_Liu__152_25.pdf 

Presentation Type: Poster

Session: 3.5c Flux estimates and atmospheric inversions from space-based GHG measurements

Session Date: Wednesday (6/16) 12:00 PM