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Impact of a Regional U.S. Drought on Land and Atmospheric Carbon
Author(s) -
Lee Eunjee,
Zeng FanWei,
Koster Randal D.,
Ott Lesley E.,
Mahanama Sarith,
Weir Brad,
Poulter Benjamin,
Oda Tomohiro
Publication year - 2020
Publication title -
journal of geophysical research: biogeosciences
Language(s) - English
Resource type - Journals
eISSN - 2169-8961
pISSN - 2169-8953
DOI - 10.1029/2019jg005599
Subject(s) - environmental science , biosphere , precipitation , land cover , primary production , atmosphere (unit) , atmospheric sciences , productivity , biosphere model , climatology , land use , ecosystem , geology , geography , meteorology , ecology , civil engineering , macroeconomics , engineering , economics , biology
The impacts of drought on regional land and atmospheric carbon are still poorly understood. Here we quantify the impact of a regional U.S. drought on land carbon fluxes (gross primary production, or GPP, and net biosphere production) and atmospheric carbon (CO 2 ) by imposing an idealized 3‐month meteorological drought in an ensemble of coupled land‐atmosphere climate simulations. The imposed drought, applied to the lower Mississippi River Valley (~500,000 km 2 ), leads to a 23% GPP reduction in the drought area in the month immediately following the drought's termination. The drought also caused GPP reductions in some remote areas through drought‐induced impacts on remote meteorology, particularly the areas adjacent to the imposed drought. In the remote areas, the induced precipitation changes are responsible for most of the anomalous land productivity. The impact of the drought‐induced meteorological anomalies on GPP is greater than that of the CO 2 anomalies by at least an order of magnitude. While their impact on GPP is secondary, the drought‐induced atmospheric CO 2 anomalies near the land surface can be as large as 3.57 ppm. The significant CO 2 anomalies cover an area up to three times of that of the imposed drought, suggesting that atmospheric transport needs to be considered in the interpretation of drought‐induced CO 2 anomalies in the atmosphere. The imposed drought also leads to column‐averaged CO 2 increases of up to 0.78 ppm, which is at the edge of the uncertainty from single soundings of current greenhouse gas observing satellites.