潮汕地区暖区暴雨分型及其环流形势特征

Classification of Warm⁃sector Hard Rain Patterns for the Chaozhou⁃Shantou Area and Analysis of the Characteristics of the Associated Circulation Situations

利用2009—2018年地面台站常规雨量观测资料以及NCEP 1°×1°再分析资料,对潮汕地区暖区暴雨进行分型,并对各型环流形势和物理量特征进行分析。结果表明:潮汕地区暖区暴雨可以分为切变型、低涡型、南风型和回流型,其中切变型和南风型暖区暴雨是主要类型,这与南亚高压、高空急流、高空槽等大环流形势有关;低涡型、回流型暴雨出现次数较少。切变线、低空急流、低涡、(西)南风风速脉动和风向辐合可作为潮汕暖区暴雨中低层天气系统的主要预报着眼点。不同类型暖区暴雨物理量特征关注点亦不尽相同:切变线暖区暴雨可分析其925 hPa水汽通量散度;南风型暖区暴雨可关注湿对流有效位能Cape值。

Using conventional rainfall observations from surface sites from 2009 to 2018 and 1°×1°reanalysis from NCEP,this work classifies the patterns of hard rain in the Chaozhou⁃Shantou area in Guang⁃dong province and analyzes the characteristics of the circulation situations and physical quantities associated with each of the patterns.The results are shown as follows.The warm⁃sector hard rain in this area can be grouped into the following patterns of shears,vortexes,southerly winds and return flows,among which the patterns of shears and southerly winds dominate.The warm⁃sector hard rain is related with such large⁃scale situations as the South Asia high,upper⁃level jet streams and troughs.Hard rains of the patterns of vortexes and return flows take place less frequently.In forecasting the warm⁃sector hard rain in this area,the shear,low⁃level jet stream,vortex,southwesterly(southerly)wind speed pulsation and wind direction convergence are the main mid⁃and low⁃level synoptic systems to be focused on.With different types of warm⁃sector hard rain,the physical quantities to be focused on vary:the divergence of water vapor flux at 925 hPa should be analyzed if the warm⁃sector hard rain is of the shear pattern and the value of convective available potential energy(CAPE)should be focused on if it is of the southerly wind pattern.