2012年11月吉林省东南山区两次雨转暴雪过程对比分析

摘要

Based on the conventional observation data and Doppler radar data, two raining to snowing processes which happened in the southeastern mountain area of Jilin province during 5-6 and 11-12 Nov. 2012 have been comparative analyzed. The results show that the two processes happened in the area of occluded frontal and the surface warm cyclone. Dynamic uplift and orographic lifting of Changpai were in favor of the occurrence of heavy rainfall. The different paths of weather systems led to the different locations of heavy rainfall. Sufficient water vapor at low level played an important role in the occurrence of heavy rainfall. The water vapors of these two processes came from southeast warm air and the southwest jet. The main reasons of raining to snowing and continuous snowing were that the coming cold air weather system led to the temperature reduction.%利用常规资料、探空资料和雷达垂直风廓线资料，对2012年11月5-6日、11-12日吉林省东南部山区两次雨转暴雪过程进行了对比分析。结果表明，两次过程的影响系统是高空冷涡配合不同发展阶段的地面气旋东移发展，强降水性质分别为锢囚锋区降水和地面气旋的暖区降水。系统的动力抬升条件与长白山区地形抬升作用结合有利于强降水的产生和加强，当天气系统从不同路径进入山区，强降水的位置不同。低层充足的水汽是大到暴雪发生的重要条件之一，两次过程的水汽分别来自东南风带来的海上暖湿气流和槽前西南急流的水汽输送。雨转雪和纯雪持续的主要原因是系统带来的冷空气降温，气温的降低可以促使雨转雪的发生。