孟加拉湾风暴“罗纳”对我国华南地区强降水的影响  

Impact of ROANU Storm over the Bay of Bengal on Heavy Rainfall in South China

作　　者：柳龙生 许映龙 LIU Longsheng;XU Yinglong(National Meteorological Center,Beijing 100081,China)

机构地区：[1]国家气象中心,北京100081

出　　处：《干旱气象》2020年第2期271-279,300,共10页Journal of Arid Meteorology

基　　金：国家自然基金项目“对流层中高层非绝热加热对我国近海热带气旋突然增强影响的机理研究”(41775048);国家气象中心预报员专项(Y201911)共同资助.

摘　　要：利用NCEP/NCAR FNL再分析资料、CMORPH卫星-地面自动站融合降水数据以及FY-2G卫星反演的云顶亮温TBB资料,针对2016年5月19-20日孟加拉湾风暴"罗纳"给我国华南地区暴雨过程带来的影响进行诊断分析。结果表明:华南地区500 hPa高空槽的发展和维持为暴雨的发生提供重要的大尺度环流背景,高低空急流耦合激发MCS的发展,促使降水增幅,孟加拉湾风暴"罗纳"及其北侧副热带西风急流为华南地区暴雨的发生提供重要的水汽通道。此外,在"罗纳"东北移动过程中,315 K等熵面上正位涡平流东传显著,在高空急流辐散抽吸作用下,华南低层出现气旋性涡旋,为暴雨的发生发展提供动力条件。可见,孟加拉湾风暴"罗纳"外围云团不仅向华南强降水区输送水汽,而且高温高湿的气流进一步加剧了降水区的层结不稳定,积累了不稳定能量。Based on NCEP/NCAR FNL reanalysis data, merged hourly gridded precipitation product from CMORPH-AWS data and retrieved TBB data from FY-2 G satellite, the impact of ROANU storm over the Bay of Bengal on the torrential rainstorm in South China from 19 to 20 May 2016 was diagnosed and analyzed. The results show that the development and maintenance of upper trough on 500 hPa over South China provided important large scale environment background for the occurrence of heavy rainfall, and the coupling of high and low level jet stimulated the development of MCS(mesoscale convective system), which promoted the heavy rainfall. Accompanied with the northern subtropical westerly jet, the ROANU storm over the Bay of Bengal supplied important water vapor channel for the occurrence of heavy rainfall in South China. In addition, during the moving northeastward of ROANU, the positive potential vorticity advection propagating eastward was significant on isentropic surface of 315 K, and the divergence and pumping of upper jet resulted in cyclonic vortex in lower level of South China, which provided dynamic condition for the occurrence and development of rainstorm. So the peripheral cloud cluster of storm ROANU over the Bay of Bengal not only transported water vapor to the heavy precipitation area of South China, but also the warm and moist airflow further strengthened stratification instability and accumulated unstable energy.

关 键 词：孟加拉湾风暴 急流 水汽 等熵位涡 湿位涡 

分 类 号：P458.124[天文地球—大气科学及气象学]