基于三光谱带的大气散射效应校正方法

大气散射效应作为CO₂反演的主要误差源，严重影响了全球大气CO₂卫星产品的应用研究。气溶胶作用以及气溶胶与地表综合作用是大气散射的重要来源。基于O₂-A，CO₂ 1.6和2.06 μm三个光谱带中的强、弱吸收峰和连续谱，从大气气溶胶光学厚度和地表反照率的角度，分析三光谱带具有的相关信息，提出改进的全物理反演方法，对相关性很强的气溶胶光学厚度和地表反照率这两个散射相关参数进行同步反演，实现大气CO₂反演中的散射效应校正。模拟计算气溶胶影响、气溶胶和地表反照率两者综合影响导致的CO₂反演误差，并进行校正，极端情况下导致的8% CO₂反演误差可校正到1% 内，气溶胶类型差异导致最高达10%的散射影响可校正到2%内，显示了方法的有效性，同时通过对校正效果的评估，表明该方法应用于卫星数据高精度反演的潜力，也指出了实际应用时需要关注的问题。

Correction Method of Atmospheric Scattering Effect Based on Three Spectrum Bands

As a major error of CO₂ retrieval, atmospheric scattering effect hampers the application of satellite products. Effect of aerosol and combined effect of aerosol and ground surface are important source of atmospheric scattering, so it needs comprehensive consideration of scattering effect from aerosol and ground surface. Based on the continuum, strong and weak absorption part of three spectrum bands O₂-A，CO₂ 1.6 μm and 2.06 μm, information of aerosol and albedo was analyzed, and improved full physics retrieval method was proposed, which can retrieve aerosol and albedo simultaneously to correct the scattering effect. Simulation study on CO₂ error caused by aerosol and ground surface albedo CO₂ error by correction method was carried out. CO₂ error caused by aerosol optical depth and ground surface albedo can reach up to 8%, and CO₂ error caused by different types of aerosol can reach up to 10%, while these two types of error can be controlled within 1% and 2% separately by this correction method, which shows that the method can correct the scattering effect effectively. Through evaluation of the results, the potential of this method for high precision satellite data retrieval is obvious, meanwhile, some problems which need to be noticed in real application were also pointed out.