乌鲁木齐市冬季典型污染事件气象过程分析

采用数值模拟与观测资料相结合的方式,对乌鲁木齐市2008年1月10-15日的冬季典型重污染气象过程进行了分析.结果表明:乌鲁木齐市存在严重污染且与当地气象条件密切相关,其ρ(PM10)峰值往往对应近地面风场风向转变和低风速情况.边界层及上层大气持续存在的强稳定层结是影响乌鲁木齐市近地面空气ρ(PM10)变化的重要因素.天山山脉、乌鲁木齐河谷、准噶尔盆地及吐鲁番盆地间形成的山谷风局地环流配合辐射逆温,是形成乌鲁木齐市夜间深厚逆温的重要原因.深厚的夜间逆温在减少污染物向上扩散的同时也大大降低了上下动量的交换,造成地面静风频率的增加,减少了大气污染物平流输送的能力.

Meteorology Analysis of Typical Winter Air Pollution in Urumqi City

The meteorology of a typical air pollution episode in Urumqi City was investigated by combining observed data and the WRF meteorology model from January 10th to 15th,2008.The results showed that Urumqi City was experiencing serious air pollution,and the situation was closely related to the local meteorological conditions.The peak mass concentration of PM10 was always linked with low wind speeds near the ground.The very stable vertical temperature profile in the upper air was another major reason for the serious air pollution.Furthermore,the local circulations of valley and mountain breezes created by Tian Mountain,Urumqi Valley,Jungar Basin and Turpan Basin,and the advection inversion,were the determining factors of the thick inversion in Urumqi at night.The thick inversions reduced the vertical exchange of momentum and simultaneously increased the frequency of calm wind,which decreased the transport of local air pollutants out of Urumqi City.