1909号台风“利奇马”登陆后强降水分布特征

The distribution of torrential rain after landfalling of Typhoon“Lekima”(1909)

利用逐小时加密观测站资料、三源融合降水资料以及NCEP/NCAR再分析数据,分析了2019年第9号台风"利奇马"登陆后强降水的分布及演变特征,并对不同时段内与强降水落区有关的大尺度环境条件及水汽条件等因素进行了分析。结果表明:"利奇马"登陆后强降水范围出现了三次增幅,分别出现在登陆后3 h、登陆后14 h和次日清晨。进一步分析发现降水效率在登陆后也明显增加,第一次强降水主要由台风本体降水造成,并与低空急流的维持以及水汽输送的贡献有关;第二次降水增幅与北侧螺旋雨带的稳定维持密切相关,另外干冷空气的侵入也是造成降水结构非对称的原因;第三次在山东半岛出现的强降水与台风倒槽和干冷空气的叠加形成的锋生作用有关。

The distribution and evolution characteristics of torrential rain of Lekima(1909)after its landfalling in China was researched based on hourly automatic weather station observations,three source merged precipitation data and NCEP/NCAR reanalysis data.The precipitation distribution and its relationship to large scale circulation and moisture flux were also analyzed.The results were as follows:there are three rainfall reinforcements after Lekima s landfalling,which happen at 3 hours,14 hours and second morning after landfalling.Further study show that the rain rate after landfalling has also increased.The first distribution of heavy rainfall was mainly coursed by symmetric structure of typhoon circulation resulted from the maintenance of low-level jet and vapor flux.The second rainfall reinforcement closely related to the development and immobility of northern spiral rain band.The intrusion of dry cold air also contributed to asymmetric structure of rainfall.The third torrential rainfall happened in Shangdong Peninsula was resulted from the overlap of inverted typhoon trough and cold dry air.