关键词: 气象干旱, SPEI, 多时间尺度, 时空变化特征, 新疆

Abstract:

Based on the 1981−2018 China meteorological forcing dataset, the standardized precipitation evapotranspiration index (SPEI) was calculated for different time scales. The Mann−kendall (M−K) test and Sen's slope method were used to analyze the spatial and temporal characteristics of meteorological drought in Xinjiang, including trends of change, frequency of occurrence and duration. This study endeavored to provide a scientific basis for the formulation of strategies for drought prevention and mitigation in Xinjiang. Results showed that: (1) from 1981 to 2018, the climate of Xinjiang exhibited a non−significant trend of aridification, with the proportion of drought−affected area decreasing at a rate of 0.845 percentage points per decade in a non−significant manner. Both spring and summer climates showed a non−significant trend of aridification, while autumn meteorological droughts significantly intensified after 2005 and winter had tended to become wetter after 1997. (2) The spatial distribution of seasonal drought based on the SPEI−3 in Xinjiang was regionally distinct. Significant drought−affected areas were observed in spring, summer and autumn, with the intensified drought concentrated in the Tarim basin and a few eastern regions. During the winter, 57.82% of the area in Xinjiang exhibited a non−significant trend of wetting, 29.23% showed a significant trend of wetting, and only 0.03% showed a significant drought trend. The remaining areas showed a non−significant drought trend. (3) The spatial distribution of drought frequency at monthly, seasonal, and annual scales was relatively consistent, with the eastern region being a high−frequency drought zone. The average annual frequency of drought was 36.05%, with Turpan reaching 44.97%. Interdecadal differences in drought duration across Xinjiang were minimal, with the longest average drought duration observed in 2000−2009, which lasted 3.6 months. Generally, trends of aridification have intensified in the southern and eastern regions of Xinjiang over the past 38 years, with a high frequency of droughts, there is an urgent need for measures to mitigate the adverse impacts of drought.

Key words:

 Meteorological drought, SPEI, Multiple time scales; Spatial?temporal characteristics, Xinjiang