长江中游1998年特大洪涝成因分析

ANALYSIS ON CAUSE OF THE FLOODING OVER THE MIDDLE REACHES OF YANGTZE RIVER IN 1998

应用 １００ｈＰａ、５００ｈＰａ月平均高度资料、海温、射出长波辐射（ＯＬＲ）及武汉的气温 和降水资料，对１９９８年长江中游特大洪涝的成因作了总结分析．结果表明，冬春厄尔尼诺、副 热带高压和从春到初夏期间，印度洋－西太平洋赤道辐合带（ＩＴＣＺ）南侧积云对流的异常较 强，以及冬季雨雪异常偏多等气候特点，是有利于洪涝发生的强信号．

With the data of geopotential height of 100 hPa and 500hPa, sea surface temperature (SST), outgoing long-wave radiation (OLR) and rainfall and temperature din at Wuhan observatory, the causes of flooding over the middle reaches of Yangtze River are analyzed. The results prove that the preceding intensive signs benefiting to flooding appearance are the anomalous strong EL Nino and subtropical high in -winter and spring, the abnormal vigorous cumulus convection in south to the ITCZ over Indian Ocean-West Pacific from spring to early summer and the abundant precipitation in winter.