前倾槽背景下河套地区一次强冰雹天气成因分析  

Weather Causes for a Heavy Hail under the Background of the Forward Trough in Hetao Area

作　　者：张桂莲 刘林春 赵斐 于碧馨 马素艳 荀学义 ZHANG Guilian;LIU Linchun;ZHAO Fei;YU Bixin;MA Suyan;XUN Xueyi(Inner Mongolian Meteorological Observatory,Hohhot 010051,China;Xinjiang Meteorological Observatory,Urumqi 830002,China;School of Ecology and Environment,Inner Mongolia University,Hohhot 010021,China)

机构地区：[1]内蒙古自治区气象台,内蒙古呼和浩特010051 [2]新疆维吾尔自治区气象台,新疆乌鲁木齐830002 [3]内蒙古大学生态与环境学院,内蒙古呼和浩特010021

出　　处：《沙漠与绿洲气象》2019年第4期1-8,共8页Desert and Oasis Meteorology

基　　金：中国气象局预报员专项(CMAYBY2019-019);内蒙古气象局科技创新项目(nmqxkjcx201903);内蒙古气象局暴雨创新团队项目(无项目编号)共同资助

摘　　要：利用常规观测资料、多普勒雷达资料以及NECP(1°×1°)逐6h再分析资料,对2016年9月22日内蒙古河套地区强冰雹天气成因进行分析,结果表明:在前倾槽有利的天气尺度环流背景下,中高层干冷空气叠加在低层暖湿空气上形成了对流不稳定层结条件。较大的对流有效位能(CAPE)、假相当位温θse高能区、0~6km中等强度的垂直风切变有利于强冰雹的形成。反射率因子有“钩状回波”、前侧入流缺口、后侧入流缺口;前侧入流缺口表明有上升气流,强盛的上升气流有利于空中大冰雹的增长,后侧入流缺口表明有下沉气流,有可能引起破坏性大风。基本径向速度剖面有明显的中气旋特征,强烈的辐合有利于对流风暴上升运动的进一步发展;对流风暴后侧有辐散下沉气流降落到地面,辐散风出流促使对流风暴前沿的暖湿气流强迫抬升,从而使上升运动得到进一步的加强。反射率因子剖面有弱回波区、回波悬垂且55dBZ以上的强回波核心位置超过-20℃层等温线高度以上;弱回波区左侧的回波强度高达55~60dBZ且已经接地,表明有大冰雹降落到地面。The weather causes for a heavy hail in Hetao area of Inner Mongolia on 22th September 2016 was analyzed, based on the conventional observational data, Doppler radar data and NCEP(1°×1°)every six hours reanalysis data,The main conclusions are as follows: Under the favorable largescale circulation background of the forward trough,the instability energy of atmosphere accumulated caused by dry cold air in middle-high layer superimposed on warm moist air of lower layer.The larger CAPE, high energy region of θ se and medium intensity of 0-6 km vertical wind shear favor to form heavy hail. The features of reflectivity factor can be found that such as the hook echo, the front of inflow notch and the behind of inflow notch. The front of inflow notch indicated that there is updraft which favor to form the growth of large hail. The behind of inflow notch indicated that there is downdraft which may cause destructive strong wind. The basic radial velocity profile has obviously mesocyclone characteristics, strong convergence is contribute to the develop for updraft of convective storm. There is downdraft that behind the convective storm arrived the ground. Outflow of divergent wind makes warm moist air of convective storm front forced uplifting, which makes further developing of updraft. The features of reflectivity factor profile could be found, such as the weak echo region, overhang echo and the core of reflectivity above 55 dBZ extends above 20 ℃. The echo intensity of left weak echo region up to 55-60 dBZ and already reached the ground ,which indicates that heavy hail dropped.

关 键 词：冰雹 中气旋 “钩状回波” 入流缺口 回波悬垂 

分 类 号：P458.121.2[天文地球—大气科学及气象学]