黄河下游夏初一次强对流天气过程成因分析

 利用常规观测资料、多普勒雷达资料和NCEP/NCAR再分析资料，对2008年6月25日发生在黄河下游的一次强对流天气进行了天气动力学和雷达回波分析。结果表明，这次强对流天气是在有利的大尺度环境下产生的，强对流区存在有利的水汽输送和水汽辐合，不稳定的大气层结有利于对流天气的发生，Qse高能区和Qse密集区有利于对流天气的发展，850hPa以下为较强散度辐合，800～600hPa为高空散度辐散和600hPa以下的垂直上升运动为强对流的发生、发展提供了动力条件。根据多普勒雷达资料分析，对流活动在河北境内生成，移动过程中发展，影响河南安阳时回波强度大于50dBz，径向速度图上存在中尺度辐合。

Analysis of the Causes of a Strong Convective Storm in the Lower Yellow River in Early Summer

The causes of a strong convective storm in the lower Yellow River in early summer on June 25, 2008 are diagnosed by using routine observation data, Doppler weather radar data and the NCEP/NCAR reanalysis data. It is shown that the joint effect of the high-level cold air and low-level warm air leads to the convective unstable atmosphere in knots. The shear line at 850hPa plays an important role in trigger and enhancement of convective systems over Anyang. It is also revealed that the vapor come from the Bohai Sea and Yellow Sea. The vapor convergence comes into existence in Anyang. They play a crucial role in the maintenance of strong convective storm. In the period of convective storm development, the strong convergence below 850hPa and divergence over 800hPa and below 600hPa are characteristics of divergence distribution. There exists convective ascending movement. The stronger updraft is below 600hPa. These provide favorable dynamic condition. There is high sufficient energy of Qse in the convective storm region. The energy frontal zone exists in the west of convective storm area. Doppler radar data show that the convection echo generates in Hebei Province and develops during moving to Henan. The reflectivity at 3.4° elevation of the strongest convection echo of Puyang is more than 50dBz. In the velocity field. The meso-scale convergence in Anyang is studied by analyzing the Doppler radar data also.