山东西部连续强对流天气的多尺度资料对比分析

在常规观测资料基础上,结合NCEP再分析资料、风廓线雷达、多普勒雷达和卫星云图资料,对2016年6月13-14日山东省西部连续两次强对流天气进行分析.分析表明:(1)13日夜间对流强度较14日下午剧烈.两次强对流天气都是在高空冷涡的环流背景下产生的.高空为西北气流,低层存在暖湿平流输送,13日强对流天气由低层切变线和地面辐合线触发,14日由700 hpa弱冷空气触发.(2)强对流发生前都有一定的水汽输送和辐合,下暖湿上干冷,低层辐合,中高层辐散.0℃层高度在4000m左右,-20℃层高度在7000m附近.(3)强对流发生时雷达回波强度大于45dBZ,在1.5°仰角上雷达回波最高达60 dBZ以上,中层强回波区悬垂于低层弱回波区之上.垂直累积液态水含量(VIL)高达20 kg/m2,强回波区不断有中气旋生成.13日夜间有弓形回波,垂直累积液态水含量(VIL)高于14日.风廓线资料中强的垂直风切变和风向波动对强对流天气的发生时间有指示意义.(4)冰雹、大风等强对流天气发生在狭长的冷云区前部、对流云团前部和西南部的TBB梯度区上.

Comparison Analysis of Continuous Severe Convection Weather in the West of Shandong Based on Multi-scale Data

Based on conventional observation data,NCEP reanalysis data,wind profiler radar,Doppler radar,and satellite cloud image data,two times of severe convection weather in the west of Shandong Province during June 13-14 in 2016 were analyzed.The results are shown as follows:firstly,the convection on the night of June 13 was stronger than that on the aftemoon of June 14.The two times of severe convection weather generated under the circulation background of upper cold vortex.There was northwest air current at high altitudes and warm wet advection at low altitudes.Severe convection weather was triggered by low-level shear lines and surface convergence lines on June 13 and by weak cold air at 700 hPa on June 14 respectively.Secondly,there was certain water vapor transport and convergence before the occurrence of severe convection,and it was warm and wet at low altitudes but dry and cold at high altitudes;there was convergence at low altitudes and divergence at middle and high altitudes.0 ℃ layer was at about 4 000 m,and -20 ℃ layer was at about 7 000 m.Thirdly,radar echo intensity was larger than 45 dBZ when severe convection happened,and it reached above 60 dBZ at an elevation of 1.5°,while middle strong echo zone overhung weak echo zone at low altitudes.Vertically integrated liquid (VlL) was up to 20 kg/m2,and mesocyclone generated in strong echo zone;there was bow echo on the night of June 13,and VIL was higher than that on June 14.In wind profiler data,strong vertical wind shear and fluctuation of wind direction had denotative meaning to the occurrence of severe convection weather.Fourthly,hail,gale and other severe convection weather happened in front of long and narrow cold cloud zone and convective cloud clusters as well as in southwestern TBB gradient zone.