利用多角度POLDER偏振资料实现陆地上空大气气溶胶光学厚度和地表反照率的同时反演Ⅱ.实例分析

Simultaneously Retrieving Aerosol Optical Depth and Surface Albedo over Land from POLDER's Multi-angle Polarized Measurement. Ⅱ:A Case Study

由于陆地地表反照率的复杂性,陆地上空气溶胶的反演一直是卫星对地观测的一个难点,针对这个难点,作者提出联合利用偏振反射率和总反射率提取陆地上空大气气溶胶光学厚度和地表反照率及其区域分布的反演方案,提出了利用NCEP资料订正由海拔高度引起的Rayleigh散射变化的具体方法,并利用POLDER(PO-Larization and Directionality of Earth s Reflectance)的LEVEL-1B资料进行实际反演计算,给出中国华北地区气溶胶光学厚度和地表反照率的区域分布。反演结果与地基观测进行了对比验证分析,结果表明,综合利用标量辐射和偏振信息的可以实现区域乃至全球尺度的大气气溶胶和地表反照率的定量反演。

Surface albedo and aerosol optical thickness are of two important factors for estimation of earth-atmosphere energy budget and climate change, and it is still a challenging problem to retrieve them simultaneously over land from satellite observations. Based on the characteristics analysis of atmospheric polarization, a new method is given to retrieve them simultaneously with both the radiance and polarization measurements. The distribution of aerosol optical thickness and surface albedo over North China was derived from POLDER measurements on 11 April 1997. An algorithm for correcting the effect of Rayleigh scattering due to terrain elevation is proposed. Some of the results are compared with ground-based in-situ measurements and/or that of other authors＇, which show that the results are reasonable.