【摘要】 利用常规的高低空气象观测资料、物理量场、以及卫星云图等资料,对2009年2月8日发生在山西中南部地区的区域性暴雪天气过程进行了综合分析,结果表明:这次暴雪天气过程,以500 hPa西风槽过境为背景,700～850 hPa存在明显的低空切变,300 hPa以下大气层结处于不稳定状态,湿层厚度高达200 hPa,散度的垂直分布表现为明显的低层辐合、高层辐散的对称结构,在强降雪时段450hPa以下存在明显的正负涡度对。这种物理量场的配置有利于促进低层湿空气的聚合及向上的抬升运动,为暴雪的产生提供必需的条件。更多还原

【Abstract】 Using the routine upper and lower level meteorological observation data as well as the data of physical quantity field,satellite cloud image and so on,the regional snow storm process in middle-and south-Shanxi Province on February 8,2009 was synthetically analyzed.The results show that the westerly trough on 500 hPa was as a background in the storm synoptic process,a evidence lower-level shear occured in 700~850 hPa,atmosphere structure was at the unstable state below 300 hPa,humidity stratification thickness reached 200 hPa,and the divergence vertical distribution appeared as a symmetry structure of upper-level divergence and lower-level convergence.The obvious positive and negative vorticities were below 450 hPa during the period of snow storm.The advantageous disposition of physical quantity field promoted the polymerization and the upward lifting movement of low-level wet air,and provided the essential condition for the snow storm production.更多还原