华北及其周边地区秋季气溶胶光学性质的星载和地基遥感观测

利用2004～2009年秋季臭氧监测仪的3级观测资料,分析了华北及周边地区的气溶胶光学性质。结果表明:大部分区域气溶胶光学厚度(Aerosol Optical Depth,AOD)和气溶胶紫外吸收指数(Ultra Violet Aerosol Index,UVAI)平均值分别高于0.8和0.75;高气溶胶事件发生频次统计表明,AOD高值(>0.4)频发于北京及其周边地区,UVAI高值(>1.0)频发于河北中部及南部地区;华北及其周边地区绝大多数城市平均AOD和UVAI分别高于0.7和0.60,而张家口、承德和阳泉3个城市的平均AOD和UVAI值分别低于0.6和0.65。作者进一步研究了2006年10月30日的一次霾事件中气溶胶的光学性质以及其时空分布特征。结果表明,霾由华北地区输送至渤海海域,并向东北方向输送;香河地基EZlidar激光雷达的垂直观测结果进一步表明,工业和城市型气溶胶主要集中在1500m以下,其中高浓度部分集中于650m以下,平均峰值位于285m,平均消光系数达2.15km-1;CALIOP卫星观测资料结合后向轨迹分析表明,大气低层气溶胶类型以工业和城市型气溶胶为主,而高层则由于上游大气输送沙尘粒子的混入使气溶胶类型转变为污染—沙尘型。霾事件期间,香河站CE-318太阳光度计观测的AOD平均值(标准差)从背景值0.08(0.04)升高至1.17(0.14);ngstrm指数平均值(标准差)从背景值0.90(0.10)升至1.12(0.09);核模态、积聚模态和粗模态的气溶胶粒子数柱总量均增加,其中细粒子所占比例明显升高。

Measurements of Aerosol Optical Properties over North China and Its Surrounding Areas in Autumn by Satellite and Ground Based Remote Sensing

Aerosol optical properties over North China and its surrounding areas in autumn have been studied by using Ozone Monitoring Instrument(OMI)level 3 data during 2004-2009. The average aerosol optical depth (AOD) and ultraviolet aerosol index (UVAI) over the most regions are larger than 0.8 and 0.75. High frequency of large value of AOD (>0.4) event was observed in Beijing and its surrounding areas, and high frequency of large value of UVAI event was observed in the southern and middle parts of Hebei Province. Average AOD and UVAI over the cities of North China Plain were larger than 0.7 and 0.60, while the averaged AOD and UVAI values of Zhangjiakou, Chengde, and Yangquan were smaller than 0.6 and 0.65,respectively. Satellite and ground based observations were applied to a haze event on 30 October 2006. The result indicates the haze transported from the North China Plain to the Bohai Sea. EZLidar observation results indicate that most of the polluted aerosols were in the layer less than 1 km, and the peak value of extinction coefficient is 2.15 km^-1 within the altitude of 285 m. CALIOP and back trajectory results indicate that the dust aerosol mixed with polluted aerosols in higher layer, and became polluted dust aerosols. During the haze event, AOD increased from a background value(stardard deviation) of 0.08 (0.04) to 1.17 (0.14) from the measurement of CE-318 at Xianghe station, and the Ângström index increased from 0.90 (0.10) to 1.12 (0.09). The particle size distribution indicated that the ratio of fine particles increased while all of the columns of nuclei, accumulation, and coarse mode increased.