对连续暴雨或特大暴雨的地域分和和形成规律,以及与前期天气发展过程和各种气候异常关系的研究,70年代后期进展较快。由于观测期这类暴雨出现概率较小,而我国历史洪水资料又十分丰富,因此广泛搜集与分析这些资料具有重要的意义。本文主要探讨长江1860年稀遇洪水及其暴雨前期流域低温多雨雪天气的气候异常。

This paper introduces the flood of the Yangtze River in the midsummer of 1860 and the abnormal climatic phenomena of extensive areas,long period,low temperature and cold weather before rainstorm. On the 18th of July,1860,at Yichang hydrological station of the upper reaches occured the 92,500 cubic metres per second peak discharge,which was the fifth high since 1153.According to historical documents and carving records on walls,the flood was divided into three periods:rising period,peak period and dropping period;the progress of flood formation and three peak figures during peak flood period recorded in the publication“Dong Hu Xian Zhi”were introduced and described. In early May,1860,there were some striking abnormal climatic phenomena such as snowing extensively and low temperature lasted for a long time in the middle and lower reaches of the Yangtze River,raining in some local regions in automn after rainstorm in midsummer,early snowing in winter,and exceptionally serious flood.The author describes the relation between low temperature and cold weather before the early May,and rainstorm and flood in midsummer,from the aspects of climate-earth and earth-climate,and also considers that the former in the occurence process of the latter,and it is the forewarning phenomena reflected by the earth surface. As mentioned above,at the Yangtze River region in 1860,there were continuous low temperature and cold weather,much more precipitation,and continuous and frequent catastrophic rainstorm;all these were scarcely recorded on historical flood documents.