利用MODIS数据同时反演中国近海海域气溶胶光学厚度和Junge谱指数

Simultaneous Determination of Aerosol Optical Thickness and Exponent of Junge Power Law over East China Sea Based on MODIS Data

基于中分辨率成像光谱辐射仪第15和16两个近红外通道的反射率数据和空间几何角度参量，利用Junge谱近似实际大气气溶胶模型，采用一种物理迭代法，同时反演了中国近海海洋上空气溶胶光学厚度和Junge谱指数，并对反演方法进行了验证．结果表明：在所研究的海域上空，大部分气溶胶的光学厚度处于0．02～0．17间，Junge谱指数的范围集中在2．8～3．8问，且都有从海岸到远海递减的趋势，得到了合理的气溶胶Junge谱指数与气溶胶光学厚度的空间分布．将反演结果与中分辨率成像光谱辐射仪产品和气溶胶观测网数据作对比，发现反演结果更加逼近气溶胶观测网数据的观测值，具有更高的反演准确度，在该区域具有较好的适用性，以及一定的可行性与可靠性．

Based on the reflectance data of the fifteenth and sixteenth channels in near-infrared bands and spatial geometrical angles of the moderate resolution imaging spectro-radiometer, a physical iterative algorithm was proposed, using the Junge power-law size distribution to approximate the actual atmospheric aerosol model. The algorithm was used for simultaneous determination of the aerosol optical thickness and the exponent of the Jung power law. The results show that the aerosol optical thickness over most of the studied ocean is in the range of 0.02-0.17, the exponent of the Jung power law is in the range of 2.8-3. 8, and both the aerosol optical thickness and exponent of the Jung power law have the trend of descending from coast to open sea. Therefore, the reasonable spatial distributions of the exponent of the Junge power law and aerosol optical thickness were obtained. Comparing the retrieval results with the moderate resolution imaging spectro-radiometer product and aerosol robotic network measurements, the retrieval algorithm whose results are more approach aerosd robotic network data than moderate resolution imaging spectro-radiometer product, is more accurate than moderate resolution imaging spectro-radiometer algorithm. Therefore, the retrieval method which is applied for the studied region is feasible and reliable.