淮安地区一次持续性雾霾过程阶段性特征及影响因子分析

Phase characteristics of a persistent fog and haze process and its influencing factors in Huaian area

利用2013年12月1—9日淮安市气象观测资料、空气污染监测资料和探空资料,对2013年12月初中国中东部地区一次大范围持续性重度雾霾过程的气象要素、PM2.5浓度和大气边界层特征进行了分析。结果表明:此次淮安地区持续性雾霾过程高空为偏西气流,冷空气弱且850 h Pa有暖平流输送,为雾霾持续的背景条件。在此次持续性雾霾过程中,PM2.5日平均浓度均大于0.075 mg·m-3,与能见度呈反相关关系;高质量浓度的PM2.5长时间堆积使低能见度维持,随着湿度的增大或减小,雾霾交替出现。边界层中低层维持的逆温层结不利于大气湍流、水汽垂直交换及污染物垂直扩散,为雾霾长时间维持提供了良好的热力条件;混合层高度低且上升运动弱,为此次持续性雾霾过程提供了良好的动力条件。

Based on meteorological observation data,pollution monitoring data and the sounding data on December1 to 9,2013 in Huaian,meteorological elements,concentrations of PM2. 5and characteristics of atmospheric boundary layer of a large regional sustained severe fog and haze process on early December of 2013 were analyzed. The results showthat there is westerly air flowat upper level,weak cold air and weak warm advection at 850 h Pa. They supply favorable background for this process. In the course of fog and haze,daily average concentration of PM2. 5is greater than 0. 075 mg·m^-3,and it is in a negative correlation with visibility. Long accumulation of PM2. 5high concentrations makes lowvisibility maintaining. With the increase or decrease of relative humidity,fog and haze alternate appearance. Inversion layer near the surface restrains atmospheric turbulences,vertical exchanges of water vapor as well as vertical diffusion of pollutants,which creates thermal conditions for long time maintenance of fog and haze. Mixing layer height is lowand upward motion is weak,which provides good dynamic conditions for this process.