Temporal-spatial evolution characteristics of meteorological drought in Guanzhong Basin based on SPEI drought index

Abstract

As the main agricultural area of Shaanxi Province, the Guanzhong Basin has a fragile ecology and frequent droughts. This study focuses on the intensity, duration, and frequency of meteorological droughts in Guanzhong Basin, from 1955 to 2015, and the temporal-spatial characteristics of meteorological drought were evaluated based on the standardized precipitation evapotranspiration index (SPEI). Our results show that the four SPEI values all show a decreasing trend with time, which indicates that the frequency of droughts is gradually increasing. Moreover, the frequency of meteorological droughts does not exceed 40%, with a decreasing order of light drought > moderate drought > heavy drought > extreme drought. The mild drought, moderate drought, severe drought, and extreme drought mainly occur in the eastern, west, south, and north parts of the Guanzhong Basin, respectively.