台风Lekima(1909)登陆前后动热力结构变化对浙江极端降水的影响  

ANALYSIS OF DYNAMIC AND THERMODYNAMIC STRUCTURE OF TYPHOON LEKIMA(1909) BEFORE AND AFTER ITS LANDFALL

作　　者：韩芙蓉 鹿翔 冯晓钰 吴天贻 黄嘉仪 HAN Fu-rong;LU Xiang;FENG Xiao-yu;WU Tian-yi;HUANG Jia-yi(Jinhua Meteorological Bureau,Jinhua 321000,China)

机构地区：[1]金华市气象局,浙江金华321000

出　　处：《热带气象学报》2021年第1期34-48,共15页Journal of Tropical Meteorology

基　　金：金华市气象局一般项目2019-07;金华市气象局一般项目2019-08;金华市气象局金华气象公共服务创新团队共同资助。

摘　　要：利用NCEP FNL 1°×1°的全球再分析资料、FY-2F卫星相当黑体亮温TBB资料、中国自动站与CMORPH降水产品融合的逐时降水资料和多普勒天气雷达资料,重点分析了台风Lekima(2019)发展演变过程中的动热力结构变化和水汽分布特征与浙江极端强降水之间的关系。台风Lekima(2019)近海急剧加强为具有特殊双眼壁结构的超强台风,登陆前后环境水平风垂直切变维持较小值是主导台风高强度维持的重要原因。浙江上空维持着强盛的低层辐合和高层辐散场,高低层辐散风的高强度维持使得次级环流抽吸作用强,低层旋转风和辐散风对水汽、动量和热量的输送和分布起到显著的再分配作用,而中层的辐散风风向和风速变化对螺旋云带中的中尺度对流性降水具有重要的指示意义。登陆前后台风低层东北侧(超)低空急流和中层的辐合线是此次浙江台风暴雨的关键点,业务中需密切关注登陆前后台风东北侧的低空急流的影响区域及其变化。此外,700 hPa上非地转湿Q矢量散度场能较好指示未来1小时短时强降水的落区和强度变化,同时结合垂直速度场和低层水汽辐合场来综合判断台风降水落区的效果更佳。By using the National Centers for Environmental Predictions Global Final Analysis reanalysis data, the brightness temperature data from the FY-2 F satellite, hourly precipitation data and Doppler weather radar data, the characteristics of the dynamic and thermal structure and moisture pattern of Typhoon Lekima(1909)before and after its landfall are analyzed. The relationship between the structural changes and heavy rainfall patterns in Zhejiang Province is also analyzed. The results show that Lekima rapidly strengthens into a double-eyewall super typhoon in the offshore. The weak vertical wind shear around Lekima before and after its landfall is significant for the maintenance of its intensity. Low-level convergence and high-level divergence maintain over Zhejiang, and the high intensity of high-level and low-level divergent wind is favorable for the suction effect of secondary circulation. The low-level rotational wind and divergent wind plays a significant role in the redistribution of water vapor, momentum and heat. The changes in the direction and speed of divergent wind in the middle layer are significant for the mesoscale convective precipitation in the spiral cloud band. The northeast low-level jet and the convergence area of the middle layer is essential to the heavy rainfall in Zhejiang. Besides, the divergence of wet ageostrophic Q-vector at 700 hPa can indicate the changes of the location and intensity of rainfall in an hour, and it is better to predict the location of typhoon rainfall by combining the divergence of wet ageostrophic Q-vector with vertical velocity and low-level water vapor.

关 键 词：台风Lekima 动热力结构 水汽分布 风场分解 非地转湿Q矢量 

分 类 号：P444[天文地球—大气科学及气象学]