山西北部极端降水时空演变规律及与大气环流因子的响应OA北大核心CSTPCD

Based on daily precipitation data from 28 national meteorological stations in northern Shanxi Prov-ince,China,from 1972 to 2020,temporal and spatial changes in extreme precipitation in northern Shanxi and their correlation with atmospheric circulation factors and periodic characteristics were studied using linear regres-sion,Pearson correlation analysis,continuous wavelet analysis,and cross wavelet transform analysis.The results show the following:(1)In terms of time,the eight extreme precipitation indices in northern Shanxi increased sig-nificantly in the late 1970s and from the late 2010s to the early 2000s:annual total wet-day precipitation(PRCP-TOT),number of heavy precipitation days(R10mm),soaked days(R95P),extremely wet days(R99P),maximum 1-day precipitation amount(Rx1day),and maximum 5-day precipitation amount(Rx5day).The simple daily in-tensity index(SDII)increased significantly,and consecutive wet days(CWD)also increased slightly.Precipita-tion was unusually low throughout the 1980s.(2)Spatially,the extreme precipitation indices gradually increased from northeast to southwest.From the analysis of the stations'trend change,the extreme precipitation indices of most stations showed an upward trend,with the most significant upward trend of the stations located southwest of Xinzhou City.PRCPTOT and SDII in Shuozhou City and southeast of Xinzhou City showed an increasing trend.However,days of CWD showed a decreasing trend,indicating that the probability of extreme precipitation events in Shuozhou City and the southeast of Xinzhou City was high.(3)Through wavelet transform analysis,it was dis-covered that the extreme precipitation indices in northern Shanxi had a periodic feature of recurring in approxi-mately 4 years in the past 30 years.Among the selected atmospheric circulation indices,the North Atlantic Oscil-lation Index(NAO)had the most obvious influence on extreme precipitation in northern Shanxi.The larger the NAO,the smaller the PRCPTOT,R10mm,R95p,R99p,Rx1day,Rx5day,and SDII,and the lower the CWD,the greater the probability of low rainfall and drought in northern Shanxi,which is prone to flash flooding.The re-search results can provide a scientific theoretical basis for the prevention of meteorological disasters in northern Shanxi.