江西省2009年11月9日飑线天气过程分析

Analysis on Squall Line Weather Process on November 9,2009 in Jiangxi Province

2009年11月9日江西省出现了1次飑线天气过程,造成了较严重的灾害。利用该日的常规观测、多普勒雷达等资料,对此次天气过程进行分析。结果表明:本次飑线天气过程是在江西省典型天气形势背景下发生的。深厚的高空低槽、低层切变、地面处江南倒槽中;本次天气过程前,水汽条件充足,储备了大量的不稳定能量;雷达产品中反射率因子出现弓形特征,径向速度场出现辐合带、逆风区、中气旋表征将出现大风等强天气天气;雷雨大风前的高VIL,达到或超过40 kg/m2,回波强度变化存在强弱交替的现象,当由高到低的突然减弱,预示着大风的发生;飑线天气过境时,常造成风向突变、风速突增,过境后风向将变为以前的方位。

The squall line weather process appeared in Jiangxi Province on November 9,2009,which caused serious disasters.Using the conventional observation and Doppler radar data,the weather process was analyzed.The results showed that the squall line appeared under the background of typical weather situation with deep upper low pressure trough,low-rise shear,and the ground in jiangnan inverted trough.Before the process,the unstable energy was reserved by abundant water vapor.The reflectivity factor figure of radar products appeared bow echo,the radial velocity field appeared convergent zone,upwind zone and mesocyclone,which indicated that gale would appear.The high VIL before thunderstorm met or exceeded 40 kg/m2.The echo intensity existed the strong-weak alternation,when it weakened suddenly,gale would appear.When crossing the squall line,it often causes sudden change of wind direction and sudden increase of speed.Wind would become the original direction after crossing the position.