2009年11月江苏南部一次大雾天气诊断分析

利用地面观测和探空资料及NCEP 1°×1°再分析资料,分析了2009年11月25—27日江苏南部大雾的成因。结果表明：逆温层的高度及强度与雾的浓度关系密切,弱冷暖平流有利于产生雾,但是温度平流在近地面一定高度迅速逆转使得温度层结由不稳定转为稳定更利于浓雾产生。边界层在低层辐合上升与高层辐散下沉的界面中形成逆温层,是产生浓雾的重要因素。对大雾天气进行诊断分析,有利于更加准确地对大雾天气进行数值预报,减轻此类灾害性天气的危害。

Diagnostic analysis of a heavy fog event in November of 2009 in the south of Jiangsu province

Based on the conventional observational data from weather station and sounding data as well as NCEP reanalysis data（1°×1°）,the reason for forming a heavy fog event on November 25-27,2009 in the south of Jiangsu province was analyzed.The results show that the height and intensity of inversion layer are related to the formation and status of the fog.Cold and warm weak advections are both favorable to the generation of the fog.Furthermore,temperature advection inverses quickly at certain height near the surface ground,thus causes temperature profile changing from unstable to stable stratification;and all these are beneficial to the generation of the heavy fog.The inversion layer which is formed in the interface of ascending and descending movement is the important factor of generating the heavy fog.The analysis of heavy fog event is benefit to forecast accurately,and it could reduce the damage caused by the heavy fog event.