Projections of drought characteristics in China based on a standardized precipitation and evapotranspiration index and multiple GCMs.

Droughts have destructive impacts on agricultural production; thus, drought projections are vital for the development of future drought mitigation strategies. This work aimed to project a standardized precipitation and evapotranspiration index (SPEI) at 3-, 6- and 12-month timescales for the period 2011-2100 under two representative concentration pathway (RCP) scenarios - RCP 4.5 and RCP 8.5 in mainland China and to assess the changes in various drought indices over a baseline period of 1961-2000. The spatiotemporal variations in drought characteristics (e.g., the drought occurrence time, duration, severity, peak, and frequency and the percentage of stations suffering from drought (PSSD) were estimated by the projected SPEI for the periods 2011-2040, 2041-2070 and 2071-2100. The results showed that mainland China would experience more frequent and severe droughts in the future than in the baseline period, as denoted by SPEI and the generated drought variables. In particular, drier areas of northwestern China were likely to suffer from worse drought conditions than those in other areas, with PSSD values of 60% and 81% by 2100 under the RCP4.5 and RCP 8.5 scenarios, respectively. Although the annual precipitation was projected to increase in most regions, drought conditions would still worsen because of increased the minimum and maximum air temperatures. However, the GCMs contributed more uncertainties to the projection of the SPEI than the stations or the RCPs, because the GCMs made a larger contribution to the variance (>40%). The SPEI performed better than the other indices that only accounted for the influence of a single variable. The relationship between crop yields and the three drought indices varied by month, crop (maize and cotton), and timescale (3- and 6-month). The drought projections from our study can provide invaluable information for stakeholders in developing regionally specific drought adaptation strategies in the face of climate change.