Spatio-temporal evolution and non-stationary characteristics of meteorological drought in inland arid areas

Abstract

The climate system has both non-stationary and nonlinear characteristics. The non-stationary processes such as climate change and human activities have brought severe challenges to life, agriculture and ecology in arid areas. It is of great practical significance to study the spatiotemporal variation and non-stationary characteristics of drought in arid region for adopting the countermeasures to adapt to climate change. The traditional trend change and variation analysis method was used to study the drought change characteristics, which could not effectively identify the clustering phenomenon of drought and the spatial and temporal variation of drought in different time intervals. Therefore, the method of breaks for additive seasonal and trend (BFAST) was introduced to determine the non-stationary characteristics and spatial variation of drought. In this study, a typical inland arid area was taken as the study area, and the drought was quantified by standardized precipitation evapotranspiration index (SPEI). The results show that: (1) the study area was prone to light drought and moderate drought, and the duration and intensity of drought events increased significantly after 1996; (2) The spatial distribution of drought frequency and drought intensity in different seasons were significantly different; (3) The results of BFAST analysis showed that there were four discontinuities in SPEI12 time series, which indicated that the drought in the study area had obvious non-stationary characteristics. Through the analysis of the breakpoint and drought change characteristics in the study area, the occurrence time of the breakpoint in the northern region had a certain periodicity, and the climate was in a state of aridity. The results of this study have important guiding significance for further understanding the non-stationary characteristics of drought in inland arid areas, and will promote the management of water resources and the protection of ecological environment.