一次皖北大雾的高空气象特征分析

Aerological Analysis on Once Fog in the Northern Anhui

利用常规天气图、自动站观测资料、探空站高空资料等,对2009年1月7—9日发生在安徽北部的一次持续性大雾天气进行分析,以探究大雾成因。结果发现：这次大雾的类型属于平流雾,是由西南移来的暖湿气流遇到了冷平流控制下的下垫面,空气迅速降温致水汽凝结而生成;冷暖平流的交汇是形成平流雾的基础,大量暖湿气流的缓慢移动与冷平流控制的下垫面之间的较大温差是形成平流雾的客观条件;近地层1~5 m/s的西南风或偏西风,源源不断地输送水汽,有利于大雾的产生和持续;925 hpa高度层以下,存在1~2℃的逆温层,能阻止水汽层向上发展,形成大雾并不易消散。

Based on conventional weather maps,automatic weather station observations,radiosonde stations in upper-air data,the author analyzed the persistent fog which happened in 7thto 9th,January,2009 in northern Anhui,to investigate the cause of the fog.The results showed that： the fog type was advection fog,shifted to the warm and humid air from the southwest encountered the cold advection under the control of the underlying surface,the rapid cooling of air caused condensation generated;intersection of cold and warm advection was the formation of stratospheric on the basis of the fog,the larger temperature difference between a large number of slow-moving warm air and cold advection control the underlying surface was the objective conditions for the formation of advection fog;near surface layer 1-5 m/s the southwest wind or westerly wind,a steady stream transport of water vapor,was conducive to the generation of fog and continuous;925 hpa below the level,there were 1-2℃ temperature inversion,could stop up the water vapor layer,the formation of fog was not easy to dissipate.