Abstract:
The applicability of the drought indices in different regions of Xinjiang from 1961 to 2020was studied by analyzing the variation trend,correlation,and drought frequency of four meteorological drought indices of the precipitation anomaly percentage(PA),the standardized precipitation evapotranspiration index(SPEI),the self-calibrating Palmer drought severity index(scPDSI) and meteorological drought comprehensive index(MCI),and comparing them with historical disasters.The results showed that the scPDSI and MCI indices increased significantly,the drought degree showed a decreasing trend,and the consistency rate of the drought monitoring results was high.The variation trend of the PA index was stable,but it was in good agreement with the other three drought indices in the fullfrequency domain and high-frequency domain drought monitoring results.The SPEI index decreased significantly in eastern Xinjiang and the eastern part of southern Xinjiang,and the degree of the drought was increased,and there was a significant negative correlation with the other three indices in low-frequency domain drought monitoring results.The results of drought frequency analysis showed that there were abnormalities in the determination of PA special drought grade,especially in southern and eastern Xinjiang.Compare with the four indices and historical disasters,MCI was the best reflection of drought disasters.In general,the applicability of MCI in Xinjiang was better than the other three drought indices.In the past 60 years,MCI in different regions of Xinjiang showed an upward trend,and drought in each region was alleviated.Spatially,the probability of drought in northwestern Xinjiang was higher than that in southern and eastern Xinjiang.The probability of drought in northwest Xinjiang was higher than that in southern and eastern Xinjiang.Droughts occurred in different regions of Xinjiang during 1962-1967,1974-1977,1989-1991,1997,and 2020,and mainly occurred in spring and summer.Droughts were prone to occur in the western part of northern Xinjiang and the Ili River Valley.