中亚低涡背景下南疆西部两次强冰雹环境场对比分析  

Comparative Analysis of Two Heavy Hail under the Background of the Central Asian Vortex in the West of Southern Xinjiang

作　　者：张云惠 谭艳梅 于碧馨 黄艳[3] 

机构地区：[1]新疆气象台,新疆乌鲁木齐830002 [2]民航新疆空中交通管理局气象中心,新疆乌鲁木齐830016 [3]和田地区气象局,新疆和田848000

出　　处：《沙漠与绿洲气象》2016年第4期10-16,共7页Desert and Oasis Meteorology

基　　金：中国气象局气象关键技术集成与应用项目(CMAGJ2015M69);中国气象局预报员专项(CAMYBY2015-087)共同资助

摘　　要：利用常规资料、14：00 加密探空、NCEP1毅伊1毅再分析资料, 对比分析2013 年6月18日和2014年6月23日南疆西部两次强冰雹环境场及物理机制, 表明两次冰雹环境场有相同之处：在环流经向度较大的中亚低涡背景下,前期有明显降水,傍晚前后由中亚低涡后部西北气流下产生,高空干冷平流、低层暖湿环境、较大的垂直温度递减率及低层辐合线或切变线为冰雹天气提供了强不稳定层结和动力触发条件,为冷平流强迫类型.但两次冰雹中亚低涡位置、强度、物理机制变化等有所不同：“6 ·18” 中亚低涡压至南疆西部,低涡强,西北风大,而“6· 23”中亚低涡在巴尔喀什湖附近, 位置偏北, 低涡较弱, 西北风较小; 6· 18”偏西北气流、风 （垂直） 切变、强回波伸展高度、层结不稳定、水汽及动力等变化均较“6· 23”明显偏强;“6· 18”的0益层和-20 益层的高度均比“6·23”的低 300~400m;“6·18”低层南疆盆地偏东风日变化明显, 即傍晚到夜间增强, 山前东西风辐合促使上升运动发展, 并有明显的中尺度垂直环流圈,而“6 ·23”低层为西北风风速辐合及与偏东风的切变.By using observational data, encryption sounding data （14：00）and NECP reanalysisdata （1°×1°） , the environment and physical mechanism of two hailstorm events under thebackground of the Central Asian Vortex in the west of southern Xinjiang on June 18th, 2013 （ “6·18” ）and June 23rd, 2014 （ “6·23” ）are contrastively analyzed. The results show that the twoevents have much in common. Under the background of the Central Asian Vortex, heavy hailhappened after obviously rain with northwesterly wind at the back of vortex. The dry and cold airadvection in the high altitude, the warm and wet environment in the low layer, the large temperaturelapse rate and the convergence or shear line in the low layer added to the unstable stratification andprovided the dynamic trigger, which belonged to the cold-advection-forced-type. However, thereare also some differences between the two processes as followed. The vortex was extended to thewest of south Xinjiang in “6 · 18”while the vortex was around over Balkhash Lake. The intensity ofvortex, northwest wind, strong echo, wind shear and stratification instability in “6·18”wereobviously stronger than that in“6· 23” . The variation of water vapor and driving force were huger in“6· 18” . The height at -20 益 and0 益 layer in “6· 18”were lower about 300~400 m than that in“6· 23” . In “6 ·18” , the daily variation of easterly wind in the low layer was more clearly and therewas an obvious mesoscale vertical circulation.

关 键 词：中亚低涡 环境场 冷平流强迫 冰雹 

分 类 号：P458.121.2[天文地球—大气科学及气象学]