Analysis of climatic characteristics of meteorological drought in arid and semi-arid regions of China in recent 60 years
In order to study the variation trend of climatic characteristics of consecutive dry days(CDDS)in arid and semi-arid regions of China the variation characteristics of CDDS and their differences in the period of 1961-1990 and 1991-2020 in the study area were analyzed by using the daily precipitation data from 74 meteorological stations in arid and semi-arid regions of China from 1961 to 2022.The CDDS equal to 16 days and above were focused on,and the CDDS of 16 to 25 days,26 to 40 days,41 to 60 days and above 60 days were defined as partial drought,moderate drought,severe drought and extreme drought,respectively.The results show that there are sig-nificant differences in the occurrence times and days of CDDS for 16 days and above in arid and semi-arid climates in China.Espe-cially,the occurrence times and days of CDDS corresponding to severe drought and extreme drought in arid regions are about twice times and six times of those in semi-arid regions,respectively.Compared with the period of 1961-1990,during 1991-2020,the fre-quency of meteorological drought with different grades in the western part of the study area decreased significantly,while it increased in the central and eastern parts of the study area.In the western part of the study area,the number of drought days with different grades also decreased obviously,the number of partial and moderate drought days decreased,and the number of severe and extreme drought days increased.The significance test of difference show that there was no mutation in the frequency and days of drought with different grades at most meteorological stations in the arid and semi-arid regions.
the arid and semi-arid regionsmeteorological droughtclimate characteristicsabrupt analysis
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