2005年山东半岛特大暴风雪分析

Analysis of the Shandong Peninsula Particularly Heavy Snowstorm in 2005

利用常规资料及MM5模拟结果，对2005年12月3-22日山东半岛特大暴风雪过程进行分析，结果表明：此次过程发生在前期异常偏暖，而在强冷空气导致寒潮爆发的形势下，强海气温差、日本海后部横槽持续气旋性弯曲和强冷平流是大尺度环流背景，半岛北部一带850hPa气温下降到-12℃是出现大雪或暴雪的重要指标；中尺度分析的结果表明，冷流降雪的散度、垂直速度、涡度垂直结构不同于一般暴雨过程，其上升运动、高空辐散等局限在500hPa以下的对流层中低层，使冷流降雪由低云引起，为更深入了解冷流降雪的机制提供参考。

By using observational data and MM5 numerical simulation, the particularly heavy snowstorm event that occurred during 3rd to 22nd December 2005 in the Shandong Peninsula is analyzed. The results show that the abnormal warm temperature before the event, the strong air-sea temperature difference, continuous cyclonic curvature and strong cold advection provide the large-scale circulation fields; the strong cold air causes the out break of a cold surge. The temperature at 850 hPa descending to -12℃ or lower is the important index of snowstorm over the north coastal area of the Shandong Peninsula. In addition, the mesoscale analysis indicates that cold current snowfall is caused by low-level cloud with updrafts and upper level divergence. Its divergence, vertical velocity and vorticity are different from those of normal rainfall events, which provides an important reference for studying cold current snowfall mechanism.