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基于单多普勒天气雷达资料采用EVAP方法反演风场, 并结合径向速度、反射率因子、自动气象站和探空风场等观测资料, 对2005年12月6～7日山东半岛一次冷流暴雪过程的中尺度特征进行了深入分析, 结果表明: (1)雷达回波呈狭窄带状, 移动缓慢近乎停滞, 径向速度上存在风向切变线, 烟台和威海的暴雪不同步是冷流暴雪的典型特征;(2)首次通过雷达反演证实了逆风区实际就是风场切变在径向速度图上的反映, 垂直各层水平风场存在中尺度切变线, 且与强回波带相对应, 切变线的位置决定暴雪的落区;(3)通过雷达反演风场和风廓线共同揭示出强降雪产生时对流层中层有西北风、西南风和东北风三股气流, 明显的西南气流位于850～700 hPa, 表明冷流降雪过程并非传统认为的仅有西北冷平流, 而是不同气流辐合的结果;(4)对流层中层的西南暖平流为云的播种和反馈机制提供了有利的天气背景条件, 使得冷流降雪增强, 这在常规观测资料中无法看到.“,”Mesoscale analysis is conducted on the ocean-effect snowstorm which occurred in Shandong peninsula from 6 to 7 December 2005 by EVAP retrieved wind method based on single-Doppler weather radar data, original radial velocity, reflectivity, automatic meteorological stations and upper air chart. The results are as follows: Firstly, the radar echo with a narrow belt shape moves very slowly and almost stationary. There is wind direction shear in radial velocity, and snowstorm doesn′t occur at the same time in Yantai and Weihai. These are the symbol character of ocean-effect snowstorm. Secondly, mesoscale shear in horizontal wind is found in the retrieved wind fields show, which is corresponded with strong echo belt. The position of shear determined the area of snowstorm. Thirdly, there are three airflow, include northwest, southwest and northeast wind, and the southwest warm advection is from 850 to 700 hPa.So this snowstorm is not the pure northwest airflow. Warm advection is good for micro-physics, seed/feed mechanism strengthens, which is not obvious in normal observational data.