基于POLDER数据反演陆地上空气溶胶光学特性

Retrieval Algorithm for Optical Parameters of Aerosol over Land Surface from POLDER Data

针对利用POLDER数据反演陆地上空气溶胶光学特性和地表反射率进行研究。POLDER探测器能够提供可见光到红外的地气系统反射太阳光的反射率和偏振反射率的多方向数据。发展了一种基于多角度的总反射率和偏振反射率联合反演气溶胶光学参数的算法,根据倍加累加法矢量辐射传输模式构建查找表,反演过程中还考虑了测量数据的云检测处理,气体吸收校正和平流层气溶胶校正,通过865 nm波段总反射率和偏振反射率的模拟计算值和实际测量值的对比实现局部区域的气溶胶光学特性参数和地表反射率分布图的同时反演。并用CNES提供的POLDER气溶胶产品对反演结果进行了验证,该方法能够得到气溶胶光学厚度、折射指数、粒子有效半径和地表反射率较合理的反演结果。

The retrieval of aerosol optical properties and surface albedo based on the POLDER are proposed. POLDER provides the multi-angle data of polarization and radiance of solar radiation reflected by the earth atmosphere-surface system in the visible and near-infrared wavelengths. An algorithm that estimates the aerosol optical properties based on combining radiance with polarization is developed. A look-up table （LUT） is built which is compiled based on doubling-adding vector radiative transfer mode in an atmosphere- ground system. The clouds mask, absorbing gas corrections and stratospheric aerosol correction are considered during the process. Aerosol characteristic and the surface albedo are estimated simultaneously based on comparison of measurements by POLDER with the numerical values of 865 nm band stored in LUT. The obtained results were validated with the POLDER aerosols products supplied by CNES. The retrieval results of aerosol optical properties and surface albedo show that the algorithm is valid.