1960-2017年来长江流域暴雨特征分析

Analyses on Characteristics of Rainstorm in the Yangtze River Basin in 1960-2017

在近年长江流域极端暴雨天气日渐频发的背景下。利用1960-2017年长江流域670个雨量站逐日降水资料,分析近60 a长江流域暴雨日数和强度的时空变化特征。结果表明:长江上游主暴雨区位于嘉岷流域、中下游主暴雨区位于鄱阳湖水系,上游暴雨日数基本少于中下游,但二者的暴雨强度相当;长江流域暴雨区在4-9月发生西移北抬,其主雨区由两湖水系逐渐移至嘉岷流域。流域暴雨强度在4-9月先增强后减弱,其中长江中下游暴雨在6月份最强,嘉岷流域暴雨在7月份最强;长江中下游水系暴雨日数有显著增加趋势,上游岷沱江水系暴雨日数有显著减少趋势。各水系的暴雨强度变化趋势整体较小,但沅江-洞庭湖-长江下游干流一带暴雨强度呈显著增加趋势,岷江水系有显著减弱趋势;长江上游“百年一遇”、“五十年一遇”、“十年一遇”的暴雨强度分别为183、160、112 mm/d,长江中下游为200、174、120 mm/d。

In recent years, extreme rainstorms in the Yangtze River Basin have become increasingly frequent. In this paper, by using the daily precipitation data at 670 rainfall stations in the Yangtze River Basin during 1960-2017, the spatial and temporal variation characteristics of rainstorm days and intensity in the Yangtze River Basin in recent 60 years were analyzed. The results showed that the rainstorm areas in the upper Yangtze River were located in the Jiamin River basin, and the rainstorm areas in the middle and lower Yangtze River were located in the Poyang Lake system. The rainstorm days in the upper Yangtze River were obviously smaller than those in the middle and lower reaches, but their intensity was close;The rainstorm areas in the Yangtze River basin moved northwest from April to September, and its location gradually moved from the two lakes to the Jiamin River Basin. The intensity of rainstorm increased first and then decreased from April to September. The strongest rainstorm in the middle and lower Yangtze River occurred in June, while that in the Jiamin River Basin occurred in July;The rainstorm days in the middle and lower Yangtze River increased significantly, while that in the Mintuo River Basin decreased significantly. The variation trend of rainstorm intensity in each water system of the Yangtze River Basin was not obvious, but it in Yuan River-Dongting Lake - the main stream of the lower Yangtze River had a significant increase trend, and it in the Minjiang River system had a significant weakening trend. The rainstorm intensities of 100-year, 50-year and 10-year recurrence intervals were 183, 160 and 112 mm/d in the upper Yangtze River, and 200, 174, 120 mm/d in the middle and lower Yangtze River.