夏季江淮流域暴雨的特征及与旱涝的关系  

Characteristics of the severe rain and its relation to flood and drought in the Changjiang and Huaihe areas in summer

作　　者：赵勇[1] 钱永甫[1] 

机构地区：[1]南京大学大气科学系,南京210093

出　　处：《南京大学学报（自然科学版）》2008年第3期237-249,共13页Journal of Nanjing University（Natural Science）

基　　金：国家重点基础研究发展计划(973)(2004CB418300);国家自然科学基金(40675042)

摘　　要：基于1954—2004年全国743站降水资料和NCEP/NCAR月平均500 hPa风场资料,分析了夏季江淮流域暴雨的气候分布和年代际变化特征.结果表明,江淮流域的暴雨降水存在明显的区域差异,局地暴雨频繁,具有明显的年代际变化特征,1990年代是高值期.通过相关和合成分析发现,暴雨与洪涝的关系密切,涝年暴雨降水可占到总降水的50%左右;1990年代,暴雨降水对洪涝的贡献明显增大.本文还分析了夏季暴雨年代际变化的500 hPa环流背景,发现1990年代暴雨明显偏多的因素是:1,蒙古上空存在异常的反气旋环流,有利于中高纬地区的冷空气南下,长江以北地区盛行异常的东北风;2,西太平洋副热带高压加强,增强了低纬海洋上空水汽的向北输送.富含水汽的异常西南气流和北方地区异常的东北气流在江淮流域上空交汇,存在明显的风切变,导致较强的上升运动,易于产生强降水.Flood due to severe rain is one of serious natural disasters in China, especially in the Changiiang and Huaihe areas （Jianghuai areas）. In summer, severe rain is frequent in the Jianghuai areas. So the research on severe rain is a key issue investigated by meteorologists in China. Many previous studies more focused on analyses of severe rain on both synoptic scale and mesoseale, hut （ew on the e^imatoIogy. This paper gives the interannual and interdecadal characteristics distribution of severe rain for 1954--2004 and its relation to flood in the Jianghuai areas in summer. By use of the NCEP/NCAR monthly mean re-analysis wind data at 500 hPa and the rainfall data at 743 stations in China for 1954--2004, the climatic spatial distribution and interdecadal variation characteristics in the Jianghuai areas in summer are analyzed. The results show that severe rain in the Jianghuai areas is frequent in the local scope, and represents markedly regional difference and interdecadal variation characteristics, especially in the 1990s belonging to high value period of severe rain. By correlation and composite analysis, we find the severe rain relates closely to flood. In flood years, the mean percentage of the precipitation amount due to the severe rain to the total precipitation is about 50%, with greatly contributes to the flood in the 1990s. Furthermore, the wind background at 500 hPa due to interdecadal variation of severe rain is analyzed. The key factors which resulted in more severe rain in the 1990s are： 1. the anomaly anticyclone located over Mongolia, so the cold air at mid-high latitudes easily shifted to the south, and the anomaly northeast wind prerailed over the areas north to the Changjiang river in eastern China; 2. owing to the western Pacific subtropical high enhanced, it strengthened the water vapor transportation to the north at low latitude sea. The anomaly southwest wind with abundant water vapor and anomaly northeast wind converged over the Jianghuai areas, because of representing markedly wind d

关 键 词：暴雨量 暴雨日 暴雨比 年代际变化 江淮流域旱涝 

分 类 号：P461[天文地球—大气科学及气象学]