1998年长江流域洪涝的成因分析

利用1998年5~9月长江流域宜昌和武汉两个水文站的资料及暴雨前期土壤湿度情况, 分析了长江流域特大洪涝形成的原因, 并与1954年的强降水进行了比较。分析表明:洪涝的形成是多种因子共同作用的结果, 汛前持续多雨, 使得土壤潮湿和江河湖库水位偏高, 直接影响汛期暴雨区的水循环, 这是1998年长江流域特大洪涝形成的主要原因之一。

An Analysis of Causes for Floods in Changjiang River Valley in 1998

Using data from Yichang and Wuhan hydrological stations of the Changjiang River Valley from May to September 1998 and soil moisture data before the floods occurred, causes for the disastrous floods are analyzed and a comparison is made with 1954. The results indicate that the summer flood mainly resulted from persistent heavy rain pattern. Other factors contributing to the flood include above normal soil moisture levels and below normal evaporation before the flood season. The large scale atmospheric circulation patterns during the summer of 1998 were similar to the patterns associated with the historic heavy rain event.