利用地面AERONET/PHOTONS气溶胶观测网北京和香河站点的资料,在北京地区对POLDER12/PARAsOL卫星多角度偏振信息获得的气溶胶反演产品进行了验证分析.地基AERONET/PHOTONS观测网的体积谱分布资料分析显示,在北京地区气溶胶尺度分布的细粒子截断半径约为0.3um.将POLDER-2/PARASOL卫星气溶胶业务产品和重新定义的地基AERONET/PHOTONs细模态(半径r<0.3p.m)气溶胶光学厚度(AOT)比较,两者在北京地区有着很好的一致性,说明卫星的气溶胶业务反演产品表征了主要来自人类污染排放的细粒子气溶胶贡献.然而,由于POLDER系列卫星业务反演方法固定了埃斯屈朗(Angstrom)指数的变化范围是1.8-3.0造成了细粒子贡献占绝对主导的局限.由地基AERONET/PHOTONS观测资料的分析可知,这个埃斯屈朗指数的先验值远远大于北京地区的地基测量结果,导致了POLDER业务反演的气溶胶光学厚度偏低,埃斯屈朗指数偏高.

This study isdevoted to the regionalvalidation ofPOLDER-2/PARASOL aerosolretrieval scheme over land surfaces against independentautomatic sun-photometers located atBeijing andXianghe sites both included in AERONET (AerosolRoboticNetwork) /PHOTONS (PHOtométrie pour le TraitementOpérational de Normalisation Satellitaire).Analysis of theAERONET/PHOTONS volume size distributions shows that the finemode is verywelldefinedwith size-cutof about0.3μm overBeijing area. POLDER-2/PARASOL aerosol optical thickness (AOT) is shown to be quite consistentwith the fine fraction of the size distribution (radius<0.3μm). In other words, POLDER-2/PARASOL retrievalover land ismainly sensitive to the anthropogenic aerosolswhich are known to have important impacts on the climate, environmentaswellashumanhealth. However, the ngstr m exponentused in thePOLDER retrievalalgorithm ismuch higher than the statistic of theAERONET/PHOTONS measurements overBeijing. Thus the derivedAOT have been underestimated and the ngstr m exponents have been overestimated.