山东省一次大雾气象条件分析

Meteorological Conditions Analysis of a Heavy Fog in Shandong Province

应用常规资料对2009年11月30日-12月2日发生在山东省的一次大雾天气进行分析,结果发现:高空弱的偏西-西南气流及中低层弱的暖湿气流,近地面附近有逆温层,地面存在地形槽或均压场,为有利于大雾形成的环流形势场。t-td≤2℃,近地层相对湿度80%以上,地面风速0～3 m/s,500 hPa以下有弱辐合区,上升速度为0×10-3hPa.s-1,假相当位温处于低值区等是大雾形成的主要原因。当风速加大、上升速度增强、湿度增加、有降水产生时,或者风速加大、上升速度较小、湿度迅速降低时,均会促使大雾消散。

Using conventional data to analyze a heavy fog occurred in Shandong province on Novem ber 30 to December 2, 2009. The results showed that： weak westsouthwest airflow in the upperlevel, weak warm and humid airflow in the middlelowlevel, the inversion layer near the ground, the topogra phy trough or mean pressure field on the surface, are conducive to fog formation for the circulation field situation. The t td 〈2 ℃, nearsurface relative humidity 〉 80% , the wind speed 03 m/s on the sur face, a weak convergence zone the following 500 hPa, 0 x 103 hPa. s -1 of the vertica! speed, lower θse, are the main reasons for the formation of the heavy fog. When the wind speed increased, the vertical speed strengthened, the humidity increased, appeared precipitation, or when the wind speed increased, the vertical speed was smaller, humidity rapid decreased, will lead to the heavy fog dissipated.