抚顺“090621”冰雹多普勒雷达回波特征分析

An Analysis of Doppler Radar Echo Feature on Fushun 090621 Hail

利用常规气象资料和沈阳多普勒雷达资料,从天气背景、物理量和雷达回波演变特征分析了2009年6月21日抚顺东部地区出现冰雹天气过程的成因。结果表明:此次冰雹天气发生在地面低压带、500 hPa冷涡底部东南象限中,500 hPa冷涡移动触发低层切变线形成。冰雹发生前大气有不稳定能量和水汽输送条件。850 hPa低空冷空气的侵入加剧了大气层结不稳定,促进不稳定能量的释放,产生冰雹天气,高低空急流配合为强对流发展提供了动力条件。多普勒雷达资料表明,强对流天气有多个对流单体组成,发展强盛时有弓形、钩状和v形缺口等特征,强回波区为50～60 dBz,最大达67 dBz。径向速度有辐合区和逆风区。逆风区出现于冰雹前1 h,是冰雹出现的强信号。液态水含量为20～40 km/m2,最大垂直液态水含量为50 km/m2。出现冰雹的对流单体回波顶高9～11 km。垂直风廓线中风向、风速出现较大垂直切变。

Weather background, physical quantities and development characteristics of radar echoes, routine meteorological data and Shenyang Doppler radar data were used to analyze the causes of the hail synoptic process in the east of Fushun on June 21,2009. The results suggested ： the hail weather occurred in the surface low pressure zone and the southeast quadrant of the bottom of the 500 hPa cold eddy, which was formed by 500 hPa cold eddy mobiling and triggering the low-level shear line. Before the hail ,there were unstable energy and water vapor transportation in the atmosphere. Moreover, the intrusion of cold air at 850 hPa aggravated the unstable of atmospheric stratification, and promoted the release of unstable energy to produce hail weather. And High-low altitude jets went together to provide dynamic conditions for the severe convection developing. According to Doppler radar data analysis, strong convective weather that reflected the characteristics of arciform, hook-shaped and vshaped gap during the development of prosperity with strong echo zone 50 -60 dBz, the largest echo 67dBz consisted of several convective monomers. Meridional velocity processed convergence zone and head wind zone. The dead wind zone＇ s appearing lh before the hail was a strong signal. It was 20 -40 km/m^2 of liquid-water and 50 km/m^2 of the largest vertical liquid-water content about the hail. The convection monomer echo top could arrive 9 - 11 km in a hail. Wind direction and wind speed of vertical wind profile represented greater vertical shear.