杰拉华台风登陆后迅速减弱的原因

Analysis of the Reason of Speedily Weaken Typhoon Jelawat after Landed

杰拉华台风在浙江象山登陆后迅速减弱 ,强度衰减率大大超过历年平均值 ,对杭、嘉、湖地区影响不大。经分析认为 ,减弱的原因主要是杰拉华远离赤道辐合带 ,能量得不到补充 ,登陆时大陆高压强大 ,前期天气干旱 ,空气干燥 ,经四明山区地形摩擦 ,能量耗尽。登陆后 50 0 h Pa与 850 h Pa上下层的相对散度为负值 ,全风速显著减小。另外 ,据统计资料得出台风生成后第 1 0天后登陆对嘉兴市影响不大 。

The typhoon Jelawat landed at Xiangshan, Zhejiang and weakened speedily after landing. Its ratio of intensity attenuation was in large excess of the average and the affection on Hang Jia Hu region was not big. The main reason is that typhoon Jelawat was far away from ITCZ and couldn't gain energy. During its landing, the mainland high was very strong, the weather was drought, the atmosphere was dry. Due to its friction with the mountain terrain, the energy was given out. After it landed, the relative divergence of the upper layer 500hPa and the lower 850hPa was negative and the wind speed decreased. In addition, the effect of the landed typhoons on the 10th day or later on Jiaxing city is small according to the data of statistics. The results may serve as reference for prediction of landing typhoon.