Analysis of precipitation and drought data in Hexi Corridor, northwest China

Abstract

Precipitation data from nine meteorological stations in arid oases of Hexi Corridor, northwest China during 1970-2012 were analyzed to detect trends in precipitation and Standardized Precipitation Index (SPI) at multiple time scales using linear regression, Mann-Kendall and Spearman's Rho tests. The results found that annual precipitation in the observed stations was rare and fell into the arid region category according to the aridity index analysis. The monthly analysis of precipitation found that three stations showed significant increasing trends in different months, while on the annual level, only Yongchang station had a significant increasing trend. The analysis of SPI-12 found three main drought intervals, i.e., 1984-1987, 1991-1992 and 2008-2011, and an extremely dry year among the stations was recorded in 1986; the southeast and middle portions of the study area are expected to have more precipitation and less dry conditions.