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    2008年初武汉冰雪天气过程特征分析

    Characteristics of snow-ice weather process at the early stage of 2008 in Wuhan, Hubei province

    • 摘要: 利用实况观测资料和NCEP再分析资料对2008年初武汉市4次冰雪天气过程特征进行分析。结果表明:700—850 hPa的逆温与850 hPa以下层次的冷垫是该区降雪发生与维持的有利条件,700 hPa切变线偏在850 hPa切变线北方,风的垂直切变表明大气具有明显的斜压性,较高层次强大的西南气流在较低层次冷垫上输送大量暖湿空气。本区18日20时—19日20时暴雪发生时有较强的上升运动和较大的西南水汽输送与水汽辐合,最大西南水汽输送与水汽辐合的层次比一般暴雨过程要高,高层惯性不稳定、中层对流不稳定等都是暴雪发生的有利条件。

       

      Abstract: Based on the meteorological observation data in Wuhan and reanalysis data from NCEP, four snow-ice weather processes at the early stage of 2008 were analyzed. The results show that inverse temperature from 700 hPa to 850 hPa and cold air cushion below 850 hPa both are favorable conditions to snow weather. Wind shear line on 700 hPa locates in the north of that on 850 hPa. Vertical shear of wind indicates that atmosphere is of obvious barocliny. Southwestern air current at higher level transports large amounts of warm and moist air over cold cushion at lower levels. Snowstorm happens from 20:00 on 18th January to 20:00 on 19th January in Wuhan, and it has been found that occurrence of snowstorm requires strong upward motion, large southwestern water vapor transportation and water vapor convergence. The greatest water vapor transportation and water vapor convergence of snowstorm are generally higher than that of rainstorms. Inertial instability at high level and convective instability at middle level both are favorable conditions to the occurrence of snowstorm.

       

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