| Autor: |
Balashov, Nikolay V.1,2 (AUTHOR) nikolay.v.balashov@nasa.gov, Ott, Lesley E.1 (AUTHOR), Weir, Brad1,3 (AUTHOR), Basu, Sourish1,2 (AUTHOR), Davis, Kenneth J.4,5 (AUTHOR), Miles, Natasha L.4 (AUTHOR), Thompson, Anne M.6,7 (AUTHOR), Stauffer, Ryan M.6 (AUTHOR) |
| Předmět: |
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| Zdroj: |
Journal of Geophysical Research. Atmospheres. 9/27/2023, Vol. 128 Issue 18, p1-20. 20p. |
| Abstrakt: |
Climate extremes such as droughts, floods, heatwaves, frosts, and windstorms add considerable variability to the global year‐to‐year increase in atmospheric CO2 through their influence on terrestrial ecosystems. While the impact of droughts on terrestrial ecosystems has received considerable attention, the response to flooding is not well understood. To improve upon this knowledge, the impact of the 2019 anomalously wet conditions over the Midwest and Southern US on CO2 vegetation fluxes is examined in the context of 2017–2018 when such precipitation anomalies were not observed. CO2 is simulated with NASA's Global Earth Observing System (GEOS) combined with the Low‐order Flux Inversion, where fluxes of CO2 are estimated using a suite of remote sensing measurements including greenness, night lights, and fire radiative power as well as with a bias correction based on insitu observations. Net ecosystem exchange CO2 tracers are separated into the three regions covering the Midwest, South, and Eastern Texas and adjusted to match CO2 observations from towers located in Iowa, Mississippi, and Texas. Results indicate that for the Midwestern region consisting primarily of corn and soybeans crops, flooding contributes to a 15%–25% reduction of annual net carbon uptake in 2019 in comparison to 2017 and 2018. These results are supported by independent reports of changes in agricultural activity. For the Southern region, comprised mainly of non‐crop vegetation, annual net carbon uptake is enhanced in 2019 by about 10%–20% in comparison to 2017 and 2018. These outcomes show the heterogeneity in effects that excess wetness can bring to diverse ecosystems. Plain Language Summary: Carbon dioxide (CO2) is the main driver of climate change whose atmospheric concentration is governed by a mix of human emissions and absorption by land and ocean sinks. Understanding how these sinks will respond to climate change in the future, including in response to increasingly frequent extreme events like floods, is critical in setting reliable emission reduction targets and improving Earth system models. Here, the devastating flood of 2019 that affected the Midwestern and Southern US is examined with respect to its effects on the ability of land ecosystems to absorb CO2. The analysis is performed using NASA's GEOS model, which simulates CO2 concentrations based on a simple land model that had previously been adjusted to match global background insitu observations. In this study, fluxes are adjusted using CO2 observations from measurement towers in the U.S. Simulations covering the years of 2017–2019 are compared and indicate that parts of the affected region absorbed less CO2 in 2019 than in previous years. The results demonstrate the effects of floods on the carbon cycle are complex and warrant further study, which is needed to understand how land ecosystems will respond to climate change in the future. Key Points: A devastating flood occurred in 2019 over the Midwestern and Southern regions of the US significantly affecting ecosystem carbon cyclingNet ecosystem exchange is examined in the flood‐effected areas with NASA's GEOS modeling system from 2017 through 2019The 2019 floods caused a net reduction in Midwestern crop carbon uptake and smaller net increase in non‐crop uptake in Southern states [ABSTRACT FROM AUTHOR] |
| Databáze: |
GreenFILE |
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