摘要
利用高空、地面气象观测资料及NCEP再分析资料,对贵州铜仁2019年2月17日(简称“02·17”过程)和2月20日(简称“02·20”过程)两次冷锋后部的高架雷暴天气进行了对比分析,结果表明:(1)两次过程均受高空槽、中低层切变线及地面冷空气补充加强影响,亦受700 hPa西南急流脉动导致风速辐合触发释放不稳定能量影响。(2)逆温层“上干冷、下暖湿”的温湿层结、850-700 hPa强垂直风切变及700-500 hPa较大的垂直温度递减率、对流层中低层强比湿平流为两次过程提供了水汽、动力、热力及不稳定条件。(3)两次过程均出现强雷暴并伴有降水,但“02·17”过程湿层深厚、云顶温度低、热力不稳定层结更强、水汽辐合高度也较高,所以在午后到傍晚时段出现了雷暴并伴有冰粒或霰,夜间时段由于湿层高度的进一步抬升及低层气温的下降,所以产生了雨夹雪或雪,地势高处产生了冻雨;“02·20”过程逆温强度强、干层厚度大、湿层浅薄、云顶温度较高,受冷空气扰动的强度大,所以出现强闪电并伴有弱降水。
Based on the radio sounding and surface observation data and NCEP reanalysis data,we analyzed elevated thunderstorms behind the two cold fronts in Tongren,Guizhou Province on 17February(“02·17”process)and 20 February(“02·20”process)2019.The results show that:(1)Both processes are influenced by the high trough,the shear line in the middle and low levels,and the cold air supplement above the ground.The southwest jet pulse produces the wind speed convergence at 700 hPa,which triggers the release of unstable energy.(2)Temperature-humidity stratification of“dry and cold upper and warm and humid lower”above the temperature inversion layer,strong vertical wind shear of850~700 h Pa and a larger vertical lapse rate of temperature of 700~500 hPa and strong specific wet advection in the lower troposphere provide the two processes with water vapor,dynamic,thermal and instability conditions.(3)Severe thunderstorms and precipitation occur in both two processes.However,during the“02·17”process,the wet layer is deeper and the cloud top temperature is lower,the thermal instability stratification is stronger,and the water vapor convergence height is also higher.Therefore,thunderstorms accompanied by ice particles or graupel appear from afternoon to evening,and sleet or snow occurs at night due to the further rise of the wet layer height and the decrease of the temperature at the lower level,and freezing rain occurs at the high altitude;During the“02·20”process,the intensity of temperature inversion is thicker and steadier,the dry layer is thicker,the wet layer is shallower,the cloud top temperature is higher,and the intensity of disturbance by the cold air is higher,thereby,the intense lightning occurs and accompanies weak precipitation.
作者
胡萍
刘玉林
杨群
聂云
张李娟
冉仙果
HU Ping;LIU Yulin;YANG Qun;NIE Yun;Zhang Lijuan;RAN Xianguo(Tongren Meteorological Bureau,Tongren 554300,China;Chizhou Meteorological Bureau,Chizhou 247000,China;Yanhe Meteorological Bureau,Yanhe 565300,China)
出处
《沙漠与绿洲气象》
2022年第2期91-98,共8页
Desert and Oasis Meteorology
基金
贵州省铜仁市科技局项目(2020-23号)
贵州省科技厅项目黔科合基础[2018]1158
黔气科登[2021]07-10号。
关键词
高架雷暴
环流特征
不稳定能量
垂直风切变
elevated thunderstorm
circulation characteristics
instability energy
vertical wind shear
