Spatial differences in impacts of CO2 effect on China's meteorological droughts: Analysis from surface resistance perspective.

Studying impacts of the CO 2 effect on potential evapotranspiration (PET) and offline drought indices from surface resistance perspective is significant for understanding and accessing droughts. This study comprehensively investigated impacts of the CO 2 effect on PET and Standardized Precipitation-Evapotranspiration Index (SPEI) over China during 1971–2010 based on two simulations with and without CO 2 effect, respectively. We found that the CO 2 effect led to decreased PET and increased SPEI , and decreased drought, which showed strong spatial variations with the greatest impact over northern China (excluding westernmost part for PET). Such spatial variations had functional relationships not only with CO 2 concentration but also climatological conditions, i.e., climatological wind speed (U) and slope of vapour pressure curve (s) for PET , but climatological U , s and precipitation (P) for SPEI. Further analyses implied that climatological U (climatological U and P) determined the spatial variations in the CO 2 effect-induced PET (SPEI) changes over China during 1971–2010. [ABSTRACT FROM AUTHOR]