安徽省一次强对流天气过程分析

基于合肥新一代天气雷达产品和常规观测资料,从天气形势、不稳定能量、卫星云图、雷达回波等方面对2009年6月5日安徽省一次强对流天气过程进行了分析,揭示此类强对流天气的形成机制。结果表明,高空呈前倾槽形势且高低空具有强的垂直温度梯度,强大东北冷涡后部,贝湖阻高崩溃带来强冷空气南下;850100 h Pa呈一致的西北偏北干冷气流,河套东部上空925 h Pa存在切变线;地面能量积累明显且有2条明显复合线。高低空完美配合造成此次强对流天气过程强度强、范围广、移速快、危害大。山东、江苏境内海风锋导致的地面复合线对强对流可能有触发和加强作用;前期东北冷涡活跃和华东持续高温为强对流发生积累了大量不稳定能量。分析合肥站雷达图发现,0.5°仰角反射率因子图上阵风锋出现时间与经过区域对应地面大风发生时间和发生地区有很好的指示,能提前2030min发布大风预警。

Analysis of a Strong Convective Weather Process in Anhui Province

Based on the Hefei new generation of weather radar products and conventional observation data,a strong convective weather process in Anhui Province on June 5,2009 was analyzed from the aspects of weather conditions,unstable energy,satellite cloud images and radar echoes,revealing that such strong convective weather formation mechanism.The results showed that there was an upward trough at high altitude and a strong vertical temperature gradient at high and low altitudes,strong cold air was brought south under the strong northeast cold vortex;850-100 hPa were consistent with north-northwest dry airflow,there was a shear line at 925 hPa over the eastern part of Hetao;Ground energy accumulation was obvious and there were two obvious composite lines.The perfect combination of high and low altitude caused by the strong convective weather process intensity,wide range,fast moving speed,great harm.Ground composite lines caused by sea breeze front in Shandong and Jiangsu Province may trigger and strengthen the strong convection.Pre-northeast cold vortex and continued high temperature of East China for the occurrence of strong convection had accumulated a lot of unstable energy.Analysis of the Hefei station radar chart found that the 0.5-degree elevation reflectance factor map on the appeared time and passing area of gust front corresponding to the time and place of gale occurrence had good instructions,which can issue gale warnings 20-30 minutes in advance.