Temporal and spatial evolution of the standardized precipitation evapotranspiration index (SPEI) in the Loess Plateau under climate change from 2001 to 2050

Loess Plateau has great uncertainty on drought occurrence due to climate change. This paper analyzes the evolution of precipitation, potential evapotranspiration and standardized precipitation evapotranspiration index (SPEI) based on the Coupled Model Inter-comparison Project Phase 5 (CMIP5) data and regional downscaling model (RegCM4.0). Results indicate that, under RCP2.6 Scenario, the precipitation will increase significantly (5% confidence level) at the rate of 16.40mm/10a. However, the potential evapotranspiration is showing non-significant decreasing trend at the rate of 2.16mm/10a. Moreover, the SPEI will decrease in the south and northernmost area and increase in the central northern area of Loess Plateau. Under RCP8.5 Scenario, the precipitation will increase significantly (5% confidence level) at the rate of 19.12mm/10a. The potential evapotranspiration will non-significantly decrease at the rate of 2.16mm/10a and the SPEI is showing increasing trend almost in the whole Loess Plateau. Generally, Loess Plateau is becoming wetter in the central part under RCP2.6 Scenario and the wet area will be enlarged to almost the whole plateau under RCP8.5 Scenario. Based on the results, the water resources will increase under global warming, which may alleviate the water scarcity issue in the Loess Plateau. [Display omitted] •The evolution of precipitation, PET and SPEI from 2001 to 2050 was analyzed.•The climate forecasted data are based on the CMIP5 data and RegCM4.0.•The Loess Plateau is estimated to be wetter in the central part in RCP2.6 Scenario.•The whole Loess Plateau is estimated to be wetter in RCP8.5 Scenario.•The frequency of normal and wet event shows upward trend under climate change.