2008年湖南冻雨成因研究  

Formation Mechanism of Freezing Rain in Hunan Province in 2008

作　　者：刘志雄[1] 蔡荣辉[1] 邓见英 屈右铭[1] 蔡海朝 

机构地区：[1]湖南省气象科学研究所,湖南长沙410118 [2]湖南省娄底市气象局,湖南娄底417100

出　　处：《高原气象》2013年第2期456-467,共12页Plateau Meteorology

基　　金：湖南省气象局重点项目"湖南特大冻雨灾害形成机理与预报技术研究"资助

摘　　要：利用NCEP再分析资料、TRMM卫星资料和WRF数值预报模式,对2008年1月12日-2月2日湖南冻雨的成因进行了研究。结果表明,冻结层和融化层之间的水汽辐合和较强的上升运动是冻雨产生的两个必要条件。湖南南部强冻雨的产生需要强水汽辐合和上升运动,相对较厚的融化层和高的暖中心温度。卫星云图上在融化层能够观测到亮带,回波强度较大;弱冻雨期间云顶亮温相对较高,观测不到亮带,融化层厚度薄。当考虑真实地形影响时,冻结层在雪峰山脉的北面存在加厚过程,冷中心温度明显偏低;受高大山脉影响,融化层的水汽加强,厚度和强度比加入虚拟地形影响时偏厚偏强,中上层对流不稳定增大,上升运动明显加强;当加入虚拟地形因素影响时,上升运动减小。Using NCEP reanalysis data, TRMM satellite data, the formation mechanism of freezing rain in Hunan from 12 January to 2 February 2008 was studied through terrain sensitive experiment of WRF numerical forecasting model. The results show that the water vapor convergence and the strong upward movement between the freezing layer and the melting layer are the essential conditions for the formation of freezing rain. The strong water vapor convergenc and upward movement and relatively thick melting layer with high temperature in the center are important to the appearance of strong freezing rain in Southern Hunan. During the strong freezing rain period, bright band in the melting layer can be seen from the satellite image and radar echo intensity is strong. Meanwhile, the relatively high cloud top brightness temperature, no bright band on satellite image and thin melting layer are the features of the weak sleet pe- riod. When the influence of actual terrain considered, there is a thickening progress of the frozen layer in the north of Xuefeng mountain area with a obviously low temperature in the cold center. Under the influ- ence of big mountains, water vapor in the melting layer increases, the connective instability in the upper level of melting layer increases, the upward movement enhances and the thickness and strength of melting layer are thicker and stronger than that impacted by the virtual terrain.

关 键 词：湖南冻雨 冻结层厚度 融化层厚度 

分 类 号：P426.63[天文地球—大气科学及气象学]