江西持续性暴雨的典型大尺度环流模型

The typical large scale circulation model of persistent heavy rain in Jiangxi

利用1961—2010年共50 a的500 hPa欧亚地区历史天气图资料对江西省74次持续性暴雨天气过程的大尺度环流形势进行分析,并建立了江西省持续性暴雨天气的大尺度环流模型。结果表明,该模型中,欧亚中高纬的长波槽脊呈双阻塞高压型,两个阻塞高压分别位于乌拉尔山西侧和鄂霍茨克海西侧;我国东北地区有一低涡,且从该低涡中心至江西附近地区有一深厚低压槽(华北槽);西太平洋副热带高压位于低纬西太平洋地区,其脊线位于20 N附近,西脊点位于110 E附近,副热带高压北侧的584 dagpm线位置(115 E的纬度)位于27 N附近;华北槽后的干冷空气与副热带高压西北侧的暖湿气流持续交汇于江西地区,为持续性暴雨提供了有利于水汽输送和辐合抬升条件。500 hPa的历史天气图和NCEP资料均显示,该大尺度环流模型具有较好的普适性。

With the 500 hPa daily weather images over Eurasian region from 1961 to 2010,the large scale weather patterns of 74 persistent heavy rain cases in Jiangxi were analyzed.Based on the analysis results,the large scale circulation model for Jiangxi persistent heavy rain was established.In this model,two blocking high located in the west side of Ural Mountains and the west side of the Okhotsk Sea respectively.There was a low vortex in the Northeast China,and a deep trough（North China trough） lay from the center of the low vortex to the Jiangxi area.The west Pacific subtropical high located over western Pacific region at low latitude,its ridge line lied near 20°N,west ridge point situated near 110°E and＂584＂line was at north side of the subtropical high loacated near 27°N.The cold dry air at rear of North China trough continuously converged with the warm wet air in the northwest of West Pacific subtropical high over Jiangxi,which provided the favourable conditions of water vapor transportation and convergence uplift for persistent heavy rain in Jiangxi.Both the 500 hPa daily weather images and NCEP data weather patterns indicated that this model was applicable.