利用MODIS图像反演海岸带气溶胶光学特性

针对中国沿海地区海洋表面高反射率和强吸收性气溶胶粒子多的特点,提出了利用卫星图像反演该区域气溶胶光学特性的新算法。以MODIS图像为例进行研究,首先利用气溶胶观测站对中国海岸带气溶胶粒子的长期观测数据统计出气溶胶粒子模式;再应用线性分层离散坐标法对这些气溶胶模式计算出不同气溶胶光学厚度和不同几何条件下的表观反射率组成的查找表;然后利用MODIS长波段的图像和查找表完成浑浊水域上空的大气气溶胶光学特性的反演;最后采用清洁日地基观测结果对该算法的正确性和适用性进行了验证。

Retrieval of Aerosol Optical Characteristic over Coast with MODIS Image

Turbid water and high absorbing atmospheric aerosols are the main characters of the sea coast of China.A new algorithm for simultaneously retrieving aerosol optical characteristics and water color of turbid water is presented.The algorithm is based on the satellite data of MODerate resolution imaging spectroradiometer(MODIS).First,the aerosol model is built with the use of historical data observed by sun-photometers located in China coast areas.Second,based on the water-land-cloud discrimination capability of MODIS long wavelengths(1 240,1 640 and 2 133 nm),we establish a look-up table(LUT) of top-of-atmosphere reflectance with variation of aerosol optical thickness and geometry conditions.Third,use the LUT and the characters of long wavelengths of MODIS and retrieve aerosol optical properties.Moreover,we make field experiments to validate and improve the algorithm.The algorithm is useful in studying the atmospheric correction models of HY and FY satellite of China.Also,the algorithm can directly use CMODIS data of FY-3,China,to accurately retrieve aerosol optical characteristic of coast zone.