Statistical Characteristics of Torrential Rain in the Low Vortex Warm Region of Southwest Liangshan Prefecture in Sichuan
Based on the precipitation data,conventional ground observation,high altitude observation,ERA5 reanalysis data and FY-2G satellite TBB data in Liangshan prefecture from April to October in the past 10 years,a statistical and a synoptic analysis of the torrential rain in the low vortex warm region of southwest Liangshan prefecture in Sichuan province were carried out.The results are as follows:(1)The occurrence frequency of torrential rain in the low vortex warm region of southwest Liangshan prefecture has fluctuated with interannual variation,with the highest frequency in 2016 and 2022 but the lowest fre-quency in 2017;the torrential rain mainly occurs in summer(June-August),with the highest frequency in July;the torrential rain is characterized by short-term strong precipitation,which often occurs from evening to night,and decreases during the day.(2)The torrential rain occurs in the high-energy and high-humidity unstable stratification,and its moisture mainly comes from Bay of Benga.(3)The southwest low vortexes af-fecting Liangshan prefecture are mainly generated in the south of Western Sichuan Plateau and the north-west of Liangshan prefecture,and only a few are generated in the southwest of Sichuan Basin and the north-west of Liangshan prefecture,and a tiny minority are generated in the southwest of Panxi region;therefore,the south of West Sichuan Plateau is the main origin of convective cloud clusters in the low vortex warm re-gion of southwest Liangshan prefecture.(4)The convective cloud clusters of torrential rain in southwest low vortexes are often influenced by the mixture of blocky and banded pressure zones,and the influence range is wide;the heavy rain area often appears in the center of low vortex or the southeast of the periphery,and the precipitation is concentrated.
Liangshan prefecturesouthwest low vortexestorrential rain in warm regionhigh energy and high humidityconvective cloud clusters
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