中文摘要：

以上海市2013年冬季一次持续雾霾过程为例,根据能见度和相对湿度的地面观测资料将雾霾过程划分为干霾、湿霾、雾3种不同天气现象,对不同天气现象的气溶胶光学特性垂直分布特征进行了研究,并初步分析不同天气现象的转化机制.结果表明,3种不同天气现象的发生顺序为湿霾→干霾→湿霾及湿霾→雾→干霾→湿霾,相对湿度对能见度的影响最大,温度次之,再次是风速,而PM2.5对能见度的影响最小.CALIPSO（Cloud Aerosol Lidar and Infrared Pathfinder Satellite Observation）探测期间,存在2-3 km明显气溶胶层,且不同天气现象的气溶胶层厚度不同（雾〉湿霾〉干霾）;雾霾发生期间,1.0 km以下高度气溶胶消光能力最大;在干霾、湿霾到雾的转化过程中,球形、大粒径气溶胶增多,非球形、小粒径气溶胶减少.

英文摘要：

This study examined the vertical distribution of aerosol optical properties in different weather conditions of a pollution episode in Shanghai in the winter of 2013 and preliminarily analyzed the cause of pollution episode. Three types of weather conditions（ dry haze,wet haze and fog） were classified based on ground-level observation of visibility and relative humidity. Results showed that the dominant sequences of the three weather conditions were wet haze→dry haze→wet haze and wet haze→fog→dry haze→wet haze. Relative humidity has the most significant relationship with visibility deterioration,followed by temperature,wind speed,and PM2.5mass concentration. During the period of CALIPSO detection,an obvious aerosol layer around 2 - 3 km above ground existed,and the thickness is different in different weather conditions（ fogwet hazedry haze）. During pollution episode,the largest aerosol extinction was found below 1.0 km. In the transition process from dry haze,wet haze to fog,spherical and large grain size aerosols increased while non-spherical and small size aerosols reduced.