Impacts of recent droughts on North American terrestrial ecosystems
The frequency and severity of droughts have been increasing, and their impacts on terrestrial ecosystems have received growing attention. There has been limited research on the responses of carbon fluxes, evapotranspiration (ET), and water use efficiency (WUE) to severe and extended droughts at regional to continental scales. Here we combine a gridded carbon and water flux dataset (EC-MOD), Palmer Drought Severity Index (PDSI), a process-based ecosystem model, and agricultural statistics to examine the impacts of recent droughts on North American terrestrial ecosystems. The gridded flux dataset was upscaled from eddy covariance flux observations across North America through a data-driven approach. We assess the responses of ecosystem carbon fluxes, ET, and WUE to severe and extended droughts at the continental scale using EC-MOD. Drought can lead to significant declines in ET and subsequent decreases in carbon fluxes. The responses of WUE to drought are assessed at the annual scale. Simulations from a process-based ecosystem model and crop yield statistics are also used to assess the effects of drought on agricultural productivity and WUE. Drought is one of the main sources of the interannual variability of carbon and water fluxes in North America. Drought is expected to become more frequent and more severe during the remainder of the 21st century and therefore will likely have larger impacts on terrestrial ecosystems.
Earth Sciences, Earth Systems Research Center
Fall Meeting, American Geophysical Union (AGU)
American Geophysical Union Publications
Xiao, J., Ollinger, S., Li, F., Li, C., Frolking, S.E., Hurtt, G.C., Guerrie, R., Lepine, L.C., Asbjornsen, H. (2014) Impacts of recent droughts on North American terrestrial ecosystems, Abstract B23E-0266 presented at 2014 Fall Meeting, AGU, San Francisco, Calif., 15-19 Dec.