摘要
利用浙江省常规气象观测资料、ERA5逐小时再分析资料(0.25°×0.25°)和卫星云图等资料,分析2106号台风“烟花”在浙北东部沿海和浙西北山区产生极端降水的原因。结果表明:台风“烟花”引导气流弱,移动速度慢,其螺旋云带和本体云系范围广,台风强度维持时间长,影响浙江时间长达7 d,是造成此次极端降水的主要原因,但降水效率不高。西南急流和偏东急流为台风提供持续强盛的水汽输送,925 hPa水汽通量辐合区对未来6 h强降水落区和降水强度有一定指示意义。浙北东部沿海四明山一带和浙西北山区有中尺度辐合带长时间维持,导致中尺度对流系统不断发展,“列车效应”是造成极端降水的重要原因。此次降水地形增幅作用明显,山脉迎风坡地形使水汽辐合抬升,对流和锋生加剧,降水系统移速减慢,持续时间变长,降水量增大。
Using the conventional meteorological observation data of Zhejiang Province, the hourly reanalysis data of ERA5(0.25×0.25) and satellite cloud map data, the extreme precipitation process caused by typhoon“InFa”(2106)in the eastern coast of northern Zhejiang and the mountainous area of northwestern Zhejiang is analyzed. The results show that typhoon“In-Fa”has weak guiding airflow, moves slowly with wide range of spiral cloud belt and main cloud system, and maintains for a long time affecting Zhejiang for up to 7 days, which are the main reasons of the extreme precipitation. However, the precipitation efficiency is not high. The southwest jet flow and easterly jet flow provide sustained and strong water vapor transport for the typhoon, and the convergence area of 925hPa water vapor flux has certain indicating significance for the falling area and precipitation intensity of heavy precipitation in the next 6 hours. In the Siming Mountain area along the eastern coast of northern Zhejiang and the mountainous area of northwestern Zhejiang, the mesoscale convergence zone is maintained for a long time, resulting in the continuous development of mesoscale convective system, and the“train effect”is an important reason for extreme precipitation. The enhancement effect of topography for precipitation is significant. The windward slope topography of the mountain makes the convergence and uplift of water vapor, and the convection and frontogenesis intensifies. Therefore, the precipitation system slows down with the longer duration, resulting in increased precipitation.
作者
沈晓玲
李锋
SHEN Xiaoling;LI Feng(Shaoxing Meteorological Bureau of Zhejiang,Shaoxing 312000,China;Zhuji Meteorological Bureau of Zhejiang,Zhuji 311800,China)
出处
《海洋预报》
CSCD
北大核心
2022年第5期37-47,共11页
Marine Forecasts
基金
浙江省气象局科研项目(2021YB25)。
关键词
极端降水
急流
中尺度辐合带
地形
extreme precipitation
jet flow
mesoscale convergence zone
topography
