山西秋季一次飑线过程的云图特征及维持机制  

Cloud Image Characteristics and Maintaining Mechanism of a Squall Line in Autumn in Shanxi Province

作　　者：李斯荣[1] 苗爱梅[1] 王洪霞[1] LI Sirong;MIAO Aimei;WANG Hongxia(Shanxi Meteorological Observatory, Taiyuan 030006, China)

机构地区：[1]山西省气象台,山西太原030006

出　　处：《干旱气象》2019年第2期312-321,共10页Journal of Arid Meteorology

基　　金：山西省重点研发计划(201603D321125);山西省气象局领军人才项目(SXKLJTQ201510001)共同资助

摘　　要：利用Himawari-8卫星红外、水汽云图和FY-2E卫星可见光云图资料,以及多普勒天气雷达拼图和常规气象站、自动气象站、高空观测资料,对2017年9月21日发生在山西境内的一次飑线天气过程进行云图特征及维持机制分析。结果表明:(1)蒙古冷涡是本次飑线过程的大尺度天气影响系统,地面冷锋东移至不稳定潜势区触发了飑线云系的生成;高低空系统配置结构的转变及地面中尺度高压外流冷空气与环境风场形成的中尺度气旋和辐合线,是飑线发展和维持的机制;对流云团在地面冷锋与850 hPa切变线之间合并发展,地面中尺度高压与低压的发展促使气压梯度增大,导致飑线增强,是飑线过境时地面大风形成的原因。(2)初生阶段,飑线形成于云顶亮温低值区后侧梯度大值区、云顶纹理粗糙区、干湿边界偏湿区一侧,冷云盖略超前于飑线;发展阶段,飑线回波在云顶亮温低值区加强,并沿着亮温低值中心移动的方向移动;成熟阶段,飑线雷达回波与云顶亮温低值区重合。(3)弧状云线、上冲云顶和对流云带一侧的暗影是对流云团加强发展的前期征兆。Based on the infrared and water vapor cloud images of Himawari-8 satellite, the visible cloud images of FY-2E satellite, the composite reflectivity factor mosaic maps of Doppler radar, the observation data of conventional weather stations and automatic weather stations and radionsonde data, the cloud image characteristics and maintaining mechanism of the squall line process in Shanxi Province on 21 September 2017 were analyzed. The results are as follows:(1) The squall line weather process was caused by the large-scale Mongolia cold vortex weather system. The surface cold front moved eastward to the unstable potential area, which triggered the formation of the squall line system. The transformation of system configuration structure in high and low level of troposphere and the formation of mesoscale cyclone and convergence line from the outflow cold air of surface mesoscale high pressure and environmental wind field were the development and maintenance mechanisms of the squall line. The convective cloud clusters merged and developed between the surface cold front and 850 hPa shear line, and the development of surface mesoscale high and low pressure increased the pressure gradient, which led to the enhancement of the squall line, and further caused surface gale during the passage of the squall line.(2) At the initial stage, the squall line was formed in the large gradient area behind the low cloud-top brightness temperature region, the rough texture area of cloud-top, the wet side of the dry and wet boundary, and the position of cold cloud cover slightly moved in front of the squall line. At the development stage, the echo of the squall line strengthened in low cloud-top brightness temperature region, and it moved along the moving direction of the low value center of brightness temperature. At the mature stage, the radar echo of the squall line coincided with the low value region of cloud-top brightness temperature.(3) The arcus cloud line, the up rushing cloud-top and the shadows on one side of convective cloud be

关 键 词：飑线过程 雷暴大风 红外、水汽及可见光云图 

分 类 号：P458.1[天文地球—大气科学及气象学]