Analysis of Spatial and Temporal Variation Characteristics of Drought in Xinjiang Based on SPEI Index

Xinjiang is the largest and most arid area in China. Affected by natural geographical location and other factors, drought has become one of the typical natural disasters in Xinjiang. It has the characteristics of high frequency, wide range of influence and great harm, which has caused great losses to agriculture, forestry, ecology and economic development. Therefore, it is of great significance to analyze the spatial and temporal changes of drought in the region to reasonably respond to drought events and reduce the losses caused by drought. In this paper, the standardized precipitation evapotranspiration index (SPEI) of 53 meteorological stations was obtained. Combined with linear regression, Mann-Kendall mutation test and Morlet wavelet analysis, the SPEI index was used to analyze the seasonal and annual spatial and temporal changes and cycle extraction. The results showed that the annual scale in Xinjiang showed a trend of drought from 1961 to 2020. In space, light drought exists in most parts of Xinjiang, moderate drought mainly occurs in northern Xinjiang, severe drought exists in individual stations, and extreme drought occurs in southern Xinjiang. The main period of spring drought change in Xinjiang is 28, 12, 6a, the main period of summer is 6, 8, 15a, the main period of autumn is 16, 10, 6, 4a, the main period of winter is 13a, and the annual scale drought period is 13, 6a. Xinjiang as a whole shows a trend of drought; in terms of spatial distribution, the drought degree in southern Xinjiang is more serious than that in northern Xinjiang; the frequency of light drought and moderate drought is higher; the change of drought cycle is mainly 13a.