华南西部高架冰雹强对流天气过程的特征及成因分析  

Characteristic and Cause Analysis of Elevated Thunderstorm Hail Severe Convection Weather in Western South China

作　　者：董良淼[1] 农孟松[1] 梁俊聪 李佳颖[1] 赖珍权[1] 苏洵[1] 

机构地区：[1]广西区气象台,广西南宁530022 [2]梧州市气象台,广西梧州543002

出　　处：《广西科学院学报》2015年第2期139-147,154,共10页Journal of Guangxi Academy of Sciences

基　　金：2013年中国气象局预报员专项(CMAYBY2013-050);广西自然科学基金项目(2012XNSFAA053191)资助

摘　　要：利用常规观测资料、NCEP再分析资料及雷达资料,综合分析2001年以来华南西部3次高架冰雹强对流天气过程的环流形势、温湿风特征、触发机制、抬升机制、雷达的回波特征及成因,得到以下结论：（1）该类过程出现在春天,发生在地面锋面北侧冷气团后约600km以上区域,发生时地面气温较低。（2）发生期间空气下湿上干,低层存在逆温,850～700hPa为强风垂直切变,有利于对流风暴生长和维持,而且高空槽前正负变温使700hPa与500hPa处的垂直温度递减率加大,加剧对流不稳定性。（3）高原槽前正涡度平流东移导致强烈上升运动是触发对流的条件之一;过程的暖湿气流在850hPa附近才开始抬升,而不是从地面开始。（4）较低的0℃、-20℃等温线高度,较厚的冻结层厚度,极小的对流有效位能CAPE值导致雹体较小。（5）冰雹云系的雷达回波特征是,基本反射率不强,无明显的倾斜或悬垂回波;回波高度不高且VIL值较低,沿径向在最大反射率后部有相对较大的谱宽值。Based on conventional observation data,NCEP/NCAR reanalysis data and radar data since 2001,the characteristics of elevated thunderstorm hail severe convection weather in western South China,such as general circulation,temperature,moisture,wind,trigger mechanism,uplift mechanism,radar echo features,are analyzed.The results show that：（1）This weather usually occurred in the cold-air mass where was more than 600 km to the north of the frontal surface and surface air temperature was low in sping.（2）Dry in high levels and wet in low levels,low-level inversion and strong vertical wind shear between 700 hPa and 850 hPa made for the development and maintenance of convective storm.Positive and negative temperature in front of Plateau trough bringing about the increase of vertical temperature lapse rate enhanced convective instability.（3）A strong ascending motion caused by positive vorticity advection eastward-moving in front of Plateautrough was one of the condition which triggered off the contvecion.Warm moist air lifted near 850 hPa,not surface.（4）Lower height of 0℃level and-20℃level,thicker frozen layer fraction and little or no CAPE led to small hailstones.（5）There was not very large base reflectivity,not obvious titlt or overhang echo,high echo height and low VIL.Moreover,in the back of maximum reflectivity along the radial was relatively large spectral width value.

关 键 词：高架冰雹 逆温 触发机制 

分 类 号：P458[天文地球—大气科学及气象学]