渭河流域致洪暴雨的天气学分析

目的对渭河流域致洪暴雨进行分析,以便得出其时空分布特征、天气环流特征,以及暴雨型和天气型之间的对应关系,为致洪暴雨预报和机理研究奠定基础。方法利用1954年至2004年渭河流域70个气象站的观测资料、流域洪水灾害资料和高空天气图资料,应用统计学和天气学方法,得出近50年来渭河流域致洪暴雨的时空分布规律和天气环流特征,总结出了暴雨型和天气型等不同类型,讨论了它们之间的对应关系。结果近50年来渭河流域年均出现1次致洪暴雨过程,最多年份出现5次;致洪暴雨发生频率最高在7月上、下旬和8月上、中旬;致洪暴雨分为上游暴雨型、连阴雨中暴雨型、本区域暴雨型和叠加暴雨型4种类型,产生暴雨的大气环流形势分为低槽型、西南气流型、低涡切变型和副高控制型4种。结论渭河流域洪灾的形成与本地暴雨有密切关系,多数致洪暴雨都有低空急流相伴,低槽型和西南气流型是产生致洪暴雨的主要环流形势。

The synoptic analysis of rainstorm-causing on Weihe River

Aim To make a statistic analysis on the rainstorm-causing data in order to gain the characteristic of time-space distribution and weather circle flow and the relations between rainstorm type and synoptic type in Weihe River area,which helps rainstorm-causing forecast and principle research.Methods Adopt the observation data for seventy stations from the year 1954 to 2004 on Weihe river and the data of flood calamity and high air weather map,get the laws of time-space distribution and the characteristic of weather circle flow for rainstorm-causing in Weihe River for the recent 50 years,summarize the type for rainstorm and synoptic type and discuss the correspondent relations among them.Results In the recent 50 years,the average rainstorm-causing frequency on Weihe river is one,the most is five,the rainstorm-causing mostly takes place at the first decade and last decade of July together with early and middle decades of August.The rainstorm-causing on Weihe River can be divided into four types,including the up-valley rainstorm type;the local rainstorm type and continuosu rainstorm type and overlapping rainstorm type.The atmosphere circle flow situation for giving rise to the rainstorm-causing includes four patterns: the pattern of low dent and southwest current pattern and low whorl and cut-change pattern and vice-tropical high pressure.Conclusion The formation of flood disaster on Weihe River has affinity to the local rainstorm,the mostly rainstorm-causing with low air rapids,low dent pattern and southwest current pattern are the main circle current situation for begetting rainstorm-causing.