基于CALIOP的安徽沿淮地区霾天气溶胶类型及垂直分布特征

The analysis of aerosol type and vertical distribution characteristics along Huaihe River based on CALIOP satellite measuring

利用CALIPSO卫星气溶胶廓线数据、地面观测资料进行统计分析,给出了2012—2013年安徽沿淮地区霾日气溶胶的垂直廓线分布.基于后向轨迹及聚类分析,获得沿淮地区污染的主要来源及传输方向,并进一步利用卫星类型掩码产品(VFM)及EC再分析资料,对不同来源的气溶胶类型、气溶胶垂直分布及导致污染的典型天气形势进行分析.结果表明,沿淮地区消光系数随高度减小,霾日近地面消光系数为0.53km^(-1),约为晴空日的2.5倍.污染性天气主要为本地污染积累(占比为46%),其次为长三角区域污染带及京津冀等地污染传输作用影响.在静稳天气背景下,850 h Pa暖平流形成逆温层易导致沿淮地区本地污染,大陆污染型气溶胶为主要成分,近地面受低压上升气流影响,污染物在垂直方向上略有抬升,聚集高度为0.4~0.8 km.当西太平洋副热带高压5880位势高度等值线西伸北进,长三角区域整层大气均被高压控制,易产生污染沙尘型气溶胶,污染物聚集在近地面且浓度随高度减小.而在冷空气南下早期,850 h Pa冷平流易将京津冀地区污染传输到沿淮地区,气溶胶类型为大陆污染型气溶胶和污染沙尘型气溶胶,在1~2 km处高污染浓度最高,高于近地层.

Based on CALIPSO level 2 aerosol profile data and surface meteorological observation data,aerosol extinction feature in haze was statistically analysed along Huaihe River from 2012 to 2013. Using backward trajectory and cluster analysis method,pollution sources were investigated. Then vertical feature mask data（ VFM） and ERA Interim data were used to analyse aerosol type,vertical distribution characteristics and typical weather patterns. The results showed that aerosol extinction coefficient along Huaihe River was largest near the ground with extinction coefficient 0. 53 km^-1 and decreased obviously along with high. Local pollution was primary source with contribution ratio of 46%. Furthmore,pollution transmission from Yangtze River delta pollution zone and Beijing-tianjin-hebei was very important for the pollution event in Huai River basin. During stagnant synoptic situation,thermalinversion layer caused by warm advection at 850 h Pa resulted in local air pollution,which was composed of continental aerosol. Weak upward motion in the surface layer transported pollutants to 0.4 - 0.8 km,where aerosol concentration was higher than that on the ground. When subtropical anticyclone 5880 isopiestic line location moves northward and westward,Yangtze River delta was controlled by high pressure through whole layer of the atmosphere,which lead to polluted dust aerosol accumulation. Due to downdraft,extinction effect was strongest near surface and decreased with height. In the early stage of cold air south down,cold north-west airstream caused by cold advection at 850 h Pa brought Beijing-tianjin-hebei pollution to Huai River basin. Polluted continental aerosol and dust aerosol was main type of pollutants. The transport height of aerosols may be higher than 2 km with maximum transport being 1- 2 km.