黄淮地区两次低涡暴雨的中尺度特征分析

Analysis on mesoscale characteristics of two vortex rainstorms in the Huanghe-Huaihe regions

利用自动站资料、卫星云图、新一代天气雷达资料与NCEP再分析资料，分析了2010年7月17—19日黄淮地区低涡暴雨过程中两次强降水过程（分别简称“7．17”过程和“7．18”过程）的环境条件及其中尺度系统发生、发展演变过程。结果表明：（1）两次强降水均发生在充足的水汽输送、大的不稳定能量和较强的辐合上升运动等有利环境条件下，“7．17”过程热力条件更好，降水强度大，但降水范同小；“7．18”过程动力条件更好、强降水落区范围大，但雨强比“7．17”过程小。（2）“7．17”过程累积暴雨带落区位于气旋中心移动路径两侧约30—80km范围内，“7．18”过程累积暴雨、大暴雨带落区位于气旋中心移动路径两侧约70～100km范同内。（3）中尺度雨团（带）和短时强降水主要出现在地面中尺度气旋周围附近，地面中尺度气旋活动的不同阶段强降水落区不同。（4）卫星云图上，两次过程强降水均由发展旺盛的对流云团自西南向东北移动而产生，对流云顶亮温低至210～220K。（5）雷达回波图上，“7．17”过程涡旋特征更明显，“7．18”过程冷暖切变回波带特征更明显。两次过程中尺度雨带与大于等于43dBz的螺旋回波带对应关系较好，短时强降水和螺旋雨带上大于等于48dBz的强回波有较好的对应关系。

Observational data from surface automatic weather station （AWS）, satellite, Doppler weather radar and NCEP reanalysis were used to analyze the environmental conditions and the evolution of mesoscale systems for two severe precipitation events （respectively referred to as ＂ 7.17＂ ease and ＂7.18＂ case） originated by a vortex rainstorm in the Huanghe-Huaihe regions during July 17-19, 2010. The results showed that （1） the two cases both occurred under sufficient water vapor transport, abundant unstable energy, strong convergence upward motion and other favorable environmental conditions. There are more favorable thermal conditions and severer precipitation hut smaller areal coverage in the ＂7.17＂ case, while there are more favorable dynamic conditions and broader severe precipitation area hut lower rainfall intensity in ~he ＂ 7.18＂ case. （2） The accumulated rainstorm area in the ＂7.17＂ case is located on both sides of the movement path with 30-80 km about cyclone center, while that in the ＂7.18＂ case is 70-100 km. （3） The mesoscale rain clusters （bands） and the short-time heavy rainfall occur mainly around the mesoscale cyclones on the ground, and there are different heavy precipitation areas during their different activity stages. （4） It is seen in the satellite images that heavy precipitation in both cases is generated by convective clouds moving from southwest to northeast, whose TBB is as low as 210-220 K. （5） It can be found in the radar echo charts that in the ＂7.17＂ case the vortex is more evident while in the ＂7.18＂ case the echo band induced by cold and warm shear is. During the two events, the mesoscale rain band corresponds to the spiral echo belt with 43 dBz or greater, but the short-time heavy rainfall corresponds to strong echo with 48 dBz or greater in the spiral rain band.