中文摘要：

基于CALIOP/CALIPSO气溶胶廓线及类型产品,并综合AERONET产品、地面常规及探空资料和HYSPLIT后向轨迹模式,分析了华北地区2013年12月22-25日一次霾过程中气溶胶垂直分布特征及其成因。结果表明：低层存在均匀混合气溶胶消光层,层高及平均气溶胶消光系数（σ）霾日为0.481 km与0.766 km（-1）,无霾日为0.181 km与0.375 km（-1）,消光层之上σ呈指数衰减;500 m以下气溶胶光学厚度（AOD）对总AOD贡献霾日为47%,无霾日为36%;1 km以下,霾日体积退偏振比（VDR）与色比（CR）分别介于5%～15%与0.4～0.8,无霾日为15%～35%与0.6～1.0,霾日VDR与CR均值分别为13.883%与0.518,无霾日为26.371%与0.853。污染沙尘和烟尘为此次霾过程的主要气溶胶类型,本地排放及周边区域输送是此次霾过程中气溶胶的主要来源。小气压梯度、弱风速、高相对湿度及持续逆温层是导致此次霾事件的主要天气原因。

英文摘要：

Based on the CALIOP/CALIPSO aerosol profile and type products,AERONET products,surface observation and sounding data and HYSPLIT back trajectory model,the vertical variation characteristics of aerosols and its causes were analyzed for a haze event over north China during December 22～25,2013. It was found that there is a homogeneous mixing aerosol extinction coefficient（σ）layer respectively existed at the average altitude of 0.481 km and 0.181 km in haze days and non-haze days,and the average σ value below these altitudes were respectively 0.766 km～（-1） and 0.375 km～（-1）. Above the extinction coefficient layer σ exponential declined with altitude. AOD＇s contribution in 0～0.5 km was respectively 47% and 36% in haze days and non-haze days. Volume depolarization ratios（VDR）and color ratios（CR）respectively concentrated on 5%～15% and 0.4～0.8 in haze days below 1 km,while in non-haze days they were 15%～35% and 0.6～1.0. The average values of VDR and CR were respectively 13. 883 % and 0. 518 in haze days below 1 km,in non- haze days they were 26.371% and 0.853. Polluted dust and smoke were the major aerosol types during the haze period,and the aerosol is mostly from local and surrounding areas. Small pressure gradient,weak wind,enough water vapor,lasted inversion layer are the main synoptic reasons causing this haze event.