中国东部一场持续性大雾的诊断分析

Diagnostic Analysis on a Sustained Heavy Fog Event in the Eastern China

利用常规资料及NCEP 1°×1°的6小时再分析资料对2007年12月18—23日中国东部大范围大雾进行诊断分析,结果表明:逆温层的高度及强度与雾的浓度关系密切,弱的冷暖平流均有利于产生雾,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和高层辐散下沉的界面中形成逆温层,是浓雾产生的重要因素。

Based on the conventional observation and NCEP reanalysis data, the synoptic analysis of a rare heavy fog process occurring in the eastern China was carried out. The result shows that the height and intensity of the inversion layer are related to the formation and status of the fog, weak cold and warm advections are both advantageous to producing fog. Furthermore, the temperature advection quickly turns into reverse at some height near the surface, and thus makes temperature stratification from unstable into stable, all these are benefical to produce the heavy fog. The inversion layer which formed in the interface of ascending and descending movement is the important fact for producing the heavy fog.