Congo Basin Water Balance and Evapotranspiration Inferred from Satellite Observations of the Isotopic Composition of Water Vapor

Sarah Worden,  UCLA,  sarahrw27@g.ucla.edu (Presenter)
Alexis Anthony Bloom,  Jet Propulsion Lab, California Institute of Technology,  abloom@jpl.nasa.gov
Paul A Levine,  JPL,  paul.a.levine@jpl.nasa.gov
John R. Worden,  JPL,  john.r.worden@jpl.nasa.gov
Mingjie Shi,  PNNL,  mjshi.lh@gmail.com
Rong Fu,  UCLA,  fu@eas.gatech.edu

We quantify the spatio-temporal variability of Congo Basin surface water fluxes using satellite observations of the isotopic composition of water vapor. We estimate basin and sub-basin evapotranspiration minus precipitation (ET-P) between 2003 and 2018, and time-averaged evapotranspiration and net river fluxes to provide new insights into the water balance of the region. Our findings show that water deficits are largest and occur most frequently in four quadrants of the Congo Basin between 2003-2007, but decline thereafter. We also calculate mean ET from our water balance estimates and confirm that ET is the largest moisture source in the Congo Basin (temporally and spatially averaged ET/P > 70%). We incorporate these new ET-P and ET datasets into CARDAMOM, a terrestrial ecosystem model. We show, on a basin-scale, that ET correlates most strongly with gross primary productivity and plant available water. Our results confirm the importance of ET in modulating the Congo water cycle relative to other water sources. Moreover, declining Congo atmospheric water deficits during this time are consistent with contemporaneous observed increases in Congo biomass and suggest limited sensitivity of the coupling between Congo water and carbon cycles to climate-induced water variability. We hypothesize that most moisture transported into the basin stays in the basin, as river discharge and atmospheric moisture flux divergence are comparatively low. Therefore, high recycling rates and a pool of belowground water provide a buffer against rainfall changes, maintaining enough moisture conducive to biomass growth.

Poster: Poster_Worden_1-56_133_35.jpg 

Poster Location ID: 1-56

Presentation Type: Poster

Session: Poster Session 1

Session Date: Tue (May 9) 5:00-7:00 PM

CCE Program: Other