Evolutionary trends of drought under climate change in the Heine River basin,Northwest China

摘要

The present paper focused on the analysis of drought in the Heihe River basin based on daily precipitation data observed at 13 weather stations covered from 1961 to 2010. The spatial and temporal variation of drought was estimated by means of the Standardized Precipitation Index (SPI), linear regression analysis and inverse distance weighted analysis. The SPI series on 1-month, 3-month, 6-month and 12-month time scales were calculated. The results indicated that the drought risk was likely to increase. The drought tendency with further expanding drought coverage and the increased frequency of dryness/wetness alterations was detected. The gravity center of drought changed. Annual drought was shifting southwestward. and inter-annual drought was developing towards north, with the former being found relatively more evident.