POLDER-2PARASOL卫星气溶胶业务产品在北京地区的验证分析

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.

Validation of POLDER-2/PARASOL aerosol products over Beijing area

This study is devoted to the regional validation of POLDER-2/PARASOL aerosol retrieval scheme over land surfaces against independent automatic sun-photometers located at Beijing and Xianghe sites both included in AERONET (Aerosol Robotic Network)/PHOTONS(PHOtométrie pour le Traitement Opérational de Normalisation Satellitaire).Analysis of the AERONET/PHOTONS volume size distributions shows that the fine mode is very well defined with size-cut of about 0.3 LLm over Beijing area.POLDER-2/PARASOL aerosol optical thickness(AOT)is shown to be quite consistent with the fine fraction of the size distribution(radius<0.3μm).In other words,POLDER-2/PARASOL retrieval over land is mainly sensitive to the anthropogenic aerosols which are known to have important impacts on the climate.environment as well as human health.However,the Angstrom exponent used in the POLDER retrieval algorithm is much higher than the statistic of the AERONET/PHOTONS measurements over Beijing.Thus the derived AOT have been underestimated and the Angstrom exponents have been overestimated.