云南中部一次出现多个超级单体雹暴的强对流过程环境场和雷达回波特征  

Environmental Conditions and Radar Characteristics of a Severe Convective Hailstorm with Multiple Supercells in Central Yunnan Province

作　　者：尹丽云 梅寒 张腾飞 孙玲 金文杰 成佳丽 YIN Liyun;MEI Han;ZHANG Tengfei;SUN Ling;JIN Wenjie;CHENG Jiali(Yunnan Weather Modification Center,Kunming 650034;Qujing Meteorological Office of Yunnan Province,Qujing 655000)

机构地区：[1]云南省人工影响天气中心,昆明650034 [2]云南省曲靖市气象局,曲靖655000

出　　处：《气象》2021年第4期424-438,共15页Meteorological Monthly

基　　金：国家自然科学基金项目(41265001);云南省科技惠民专项(2016RA096);中国气象局预报员专项(CMAYBY2019-109)共同资助。

摘　　要：利用常规观测、地面加密自动站、多普勒天气雷达、NCEP(1°×1°)逐6 h再分析资料对2017年8月23日云南中部地区一次强对流风暴的环境参数和雷达回波特征进行分析,结果表明:此次强对流风暴发生在台风低压前侧、中高纬冷槽后部的强不稳定层结背景下,地面辐合线和强垂直风切变有利于对流风暴的维持和加强。强对流风暴受地形影响较为明显,共激发形成6个超级单体或类超级单体,在超级单体发展成熟前10 min,3个降雹超级单体强中心沿地形爬升,未降雹和小雹超级单体沿地形下降。6个超级单体或类超级单体呈现出中气旋或γ中尺度弱涡旋特征,最大速度对转动值超过10 m·s^(-1)时出现不同程度冰雹,冰雹直径>15 mm的超级单体在2.4°~3.4°仰角上径向速度值达到中气旋标准,冰雹直径为15~20 mm的超级单体反射率因子质心点较高,回波核前倾,具有悬垂回波、弱回波区、回波墙和三体散射特征,其零速度线后倾,辐合区高度超过-10℃层,顶部为强辐散区,-20~0℃层回波最大强度超过55 dBz,50 dBz回波厚度>6 km,垂直累积液态水含量(VIL)密度>2.2 g·m^(-3)。冰雹直径5~8 mm和未降雹超级单体回波核直立,悬垂回波特征不显著,辐合区高度偏低,辐散区厚度大于辐合区厚度,不同等温层回波强度差别小,但50 dBz回波厚度<6 km,VIL密度<2.2 g·m^(-3)。The evolution characteristics of radar echo and environmental parameters of the severe convective storm in central Yunnan on 23 August 2017 are analyzed using conventional observation data,automatic weather station data,Doppler radar data,NCEP(1°×1°)6 h reanalysis data.The main conclusions are as follows.This severe convective storm occurred under the background of strong unstable conditions caused by the front side of typhoon depression system moving westward and the rear side of mid and high latitude cold trough.Surface convergence lines and strong vertical wind shear were conducive to the maintenance and enhancement of convective storms.The severe convective storms were influenced significantly by the topography and six supercells or similar supercells were induced during the evolution of convective storms.The strong centers of three hail supercells climbed along the terrain,while the non-hail and small hail supercells descended along the terrain 10 minutes before the supercells developed to maturity.The six supercells or similar supercells had characteristics of mesocyclone or meso-γscale vortex.Hails occurred when the maximum velocity to rotation value in the supercell exceeded 10 m·s^(-1).The velocity at elevation 2.4°-3.4°reached the mesocyclone standard when the diameter of hails was bigger than 15 mm.There were the characteristics of higher reflectivity centroid point,echo nuclear tilting forward,weak echo zone,the echo wall and three-body scatter for supercells with 15-20 mm hail particles.In addition,the radial velocity showed the following characteristics.The zero velocity line tilted back,the height of the convergence zone exceeded-10℃layers of supercooled water zone,a strong divergence zone appeared at the top,the maximum echo intensity of the-20-0℃layer exceeded 55 dBz,the thickness of the 50 dBz echo was more than 6 km,and the density of vertically accumulated liquid water content(VIL)was larger than 2.2 g·m^(-3).The echo nuclear shows an upright shape,the characteristics of overhangin

关 键 词：超级单体 冰雹 TBSS 中气旋 VIL密度 

分 类 号：P458[天文地球—大气科学及气象学]