李岩 周文志

摘要利用常规和非常规气象资料、卫星云图和雷达产品资料等，对2015年5月10～11日桂林市发生的一次暴雨天气过程的成因及雷达回波特征进行了分析。结果表明，这次暴雨过程是高空槽、低层低涡、切变线、低空急流和地面锋面共同影响的结果。过程前期为暖区降水，锋面在影响桂林时，锋面前絮状云系回波容易造成雷雨大风、冰雹等强对流天气；较垂直的锋面过境时，在有利地形的作用下，雷达回波很容易看到飑线形成，强对流天气往往发生在飑线中；山脉阻挡雷达回波时会使回波快速加强，从而使强对流天气明显加剧；强对流天气容易发生在锋面后细长狭窄的强度在60 dBz以上、高度在13 km以上的回波带状中。当风廓线从高层到低层伸展为深厚的干层区域时，天气趋于稳定，强对流天气结束。

关键词暴雨；强对流；天气成因；雷达特征

中图分类号S161.6文献标识码A文章编号0517-6611（2016）04-235-06

"5.11" Guilin Heavy Rain Weather Process and Analysis of Radar Echo Characteristics

LI Yan， ZHOU Wen-zhi （Guilin Meteorological Bureau， Guilin， Guangxi 541001）

Abstract Using the conventional and unconventional meteorological data， satellite images and radar data，？causes for a heavy rain weather process in Guilin during May 10-11， 2015 and radar echo characteristics were analyzed. The results showed that the heavy rain process was influenced by high-level trough， low level vortex， shear line， level jet stream， ground front. The precipitation was in warm region at the early stage， when frontal surface influenced Guilin， flocculent cloud echo were easily lead to thunderstorms， hail and other severe convective weather； when vertical front pass through the region， under the action of favorable terrain， the radar echo was easy to see squall line formation， strong convective weather often occurred in the squall line； mountains blocking radar echo made echo quickly strengthened， thus， the strong convective weather increased significantly； strong convective weather were easy to occur in slender narrow？echo band？with strength above 60 dBz and height above 13 km. When the wind profile from top to lower stretched for deep dry area， strong convective weather ended.

Key wordsHeavy rain； Strong convection； The weather causes； Radar characteristics

桂林地处桂东北，与湖南相邻，春季冷暖气团交汇频繁，气象灾害种类多、分布广、发生频繁、危害严重。受高空槽、低层切变线和地面冷空气共同影响，2015年5月10～11日桂林市普降大雨，局部出现暴雨、雷雨大风和冰雹天气过程，雨量最大的是桂林市区磨盘山，为230.8 mm，10日20：00～11日14：00桂林站雨量68.8 mm；全市各县自北向南先后出现雷电、局部短时大风及冰雹等强对流天气。这次过程是在高空蒙古横槽转竖、配合低层切变线和地面冷空气从西中路南下影响造成的暴雨、雷雨大风和冰雹等强对流天气，其移动速度快、降水持续时间短，但降水强度强，影响范围广，为历史罕见。……