铜仁近40年暴雨气候特征及气候背景差异分析

利用1970～2009年铜仁地区10个气象观测站逐日暴雨资料和暴雨日数资料,分析了铜仁地区近40年暴雨的时空变化特征,同时还从环流形势、物理量场等对少暴雨年和多暴雨年的气候背景差异进行了分析。结果表明,铜仁雨季主要集中在主汛期（5～9月）,主汛期暴雨量的大小将决定着铜仁地区年总降雨量的多寡。少暴雨年在30°N以南的大部分地区500 hPa位势高度比多暴雨年偏高,西太平洋副热带高压西伸明显比多暴雨年偏西、强度偏强;东北路径冷空气的南下是导致铜仁地区暴雨出现的有利条件;少暴雨年孟加拉湾向北输送的水汽辐合比多暴雨年明显偏北;多暴雨年铜仁区域主要以东偏南风为主,少暴雨年则为一致的南风,且多暴雨年贵州中东部以及长江中下游地区垂直上升运动比少暴雨年强;少暴雨年OLR在孟加拉湾大部、南海南部的水汽输送区及贵州大部至我国江淮流域表现为正距平和正差异值控制,则对流活动较历史同期偏弱,同时也较多暴雨年偏弱。

Analysis on Climate Characteristic and Background of Abnormal Climate of Rainstorm in Tongren in Recent 40 Years

The spatial variation characteristics of rainstorm in Tongren Region in recent 40 years were analyzed by using daily rainstorm data and rainstorm days data from 10 weather stations in Tongren Region during 1970-2009.The climate background differences between less rainstorm years and abundant rainstorm years were analyzed from aspects of circulation situation and physical quantity field.The results showed that rainy season in Tongren mainly gather in flood season(May-Sep).The quantity of rainstorm in main flood season determined the annual total rainfall in Tongren.In the south of 30°N,500 hPa height field of less rainstorm years was higher than abundant rainstorm years.In less rainstorm years,the subtropical high over the western Pacific was located westwards and relatively stronger than abundant rainstorm years.The path of the northeast cold air was a favorable condition to the heavy rain happened in Tongren.The convergence of vapor transmission was more northerly in less rainstorm years.If OLR in less rainstorm years indicating positive anomaly and positive difference control in vapor transportation area of most parts of Bengal Bay and south of South China Sea and Guizhou Province to Changjiang and Huaihe River Basin,the convective activity would weaker than the same time in the past and abundant rainstorm years.