为了弥补地基观测气溶胶光学厚度(Aerosol Optical Depth, AOD)范围受限等缺点, 通过卫星影像反演AOD的方法逐渐兴起, 而简化气溶胶反演算法(Simplified Aerosol Retrieval Algorithm, SARA)与传统反演方法相比更具普适性。为进一步提升精度, 提出了一种非线性最优化的中分辨率成像光谱仪(Moderate-resolution Imaging Spectroradiometer, MODIS)气溶胶多参数反演方法。该方法以SARA反演的AOD为初始值, 对AOD、单次散射反照率(Single Scattering Albedo, SSA)(ω)、不对称性因子(Asymmetric Factor, ASY)(g)、地表反射率拟合参数(ρ′s=k*ρs+b)同时优化, 以期得到最优解。结果表明, 同等条件下, 非线性最优化方法明显优于SARA。单点精度验证结果与全球气溶胶自动观测网(Aerosol Robotic Network, AERONET)相比, 非线性最优化方法的相关系数为0.8118, 优于SARA的0.2624。与官方气溶胶产品(MOD04)相比, 7月6日非线性最优化方法的相关系数为0.7612, 优于SARA的0.5916; 5月3日非线性最优化方法的相关系数为0.9036, 优于SARA的0.8788。

To overcome the shortcoming of traditional ground-based methods of which the observation is limited, the method of inverting aerosol optical depth (AOD) by remote sensing image is gradually emerging. Compared with the traditional inversion methods, the Simplified Aerosol Retrieval Algorithm (SARA) is more universal. To further improve the accuracy, a nonlinear optimization method which uses multi-parameters to invert aerosol from Moderate-resolution Imaging Spectroradiometer (MODIS) is proposed. By treating the aerosol optical depth inverted by SARA as the initial value, the method optimizes the optical thickness, single scattering albedo (ω), asymmetry factor (g) and surface reflectance fitting parameter (ρ′s=k*ρs+b) simultaneously, so as to obtain the optimal solution. The results show that under the same conditions, the nonlinear optimization method is obviously superior to the SARA. The correlation coefficient of the nonlinear optimization method for single point precision verification is 0.8118, which is better than the 0.2624 of SARA. Compared with the inversion values from MODIS aerosol product (MOD04), for the case of July 6, the correlation coefficient of the nonlinear optimization method is 0.7612, which is better than 0.5916 of SARA. For the case of May 3, the correlation coefficient of nonlinear optimization method is 0.9036, which is better than 0.8788 of SARA.