桂林漓江致洪暴雨分析

Analysis on the Flood Rainstorm in the Lijiang River of Guilin

[目的]研究桂林漓江致洪暴雨。[方法]利用漓江致洪暴雨及漓江水位的观测资料,划定漓江致洪暴雨标准,通过华南致洪暴雨的时空分布、天气形势等方面的分析,对漓江的致洪暴雨进行比较系统的研究。[结果]漓江洪水与上游暴雨的持续时间、强度密切相关,上游日降水量≥100 mm或连续2 d以上日降水量≥50 mm,极易发生漓江洪涝灾害;桂林漓江汛期洪水每年4～7月都有可能发生,但多发生在5～6月;漓江洪水水位变化以10年为周期;当年最高水位低于警戒水位(145.00 m)以下时,则来年最高水位大多超过警戒水位,达146.00 m以上。造成致洪暴雨的天气类型可分为锋面型(锋面南压型、静止锋北抬型)和低涡型。桂林漓江上游是桂林地区的暴雨中心,是漓江致洪暴雨的关键区,特殊的地形为暴雨多发提供了有利的条件。[结论]该研究为漓江致洪暴雨的预报提供依据。

[Objective] The research aimed to study the flood rainstorm in the Lijiang River of Guilin.[Method] By using the observation data of flood rainstorm and water level in the Lijiang River,the flood rainstorm standard in the Lijiang River was delimited.Via the analysis on the spatial and temporal distribution,weather situation of flood rainstorm in South China,the flood rainstorm in the Lijiang River was carried out the systematic research.[Result] The flood in the Lijiang River closely related to the duration and intensity of torrential rain in the upstream.When the daily rainfall in the upstream ≥ 100 mm,or the daily rainfall in above continuous 2 d ≥ 50 mm,the big flood was easy to happen in the Lijiang River.During April-July in every year,the flood was possible to happen in the flood season in the Lijiang River but mainly happened during May-June.The period of flood water level variation in the Lijiang River was ten years.When the highest water level was lower than the warning stage（145.00 m） in the year,most of highest water level in the next year surpassed the warning stage and reached above 146.00 m.The weather type which caused the flood rainstorm could be divided into the frontal surface type（frontal surface south-pressure type,stationary front north-lift type） and the low vortex type.The upstream in the Lijiang River of Guilin was the rainstorm center in Guilin area and the key zone of flood rainstorm in the Lijiang River.The special terrain provided the favorable condition for the multi-occurrence of rainstorm.[Conclusion] The research provided the basis for the forecast of flood rainstorm in the Lijiang River.