Investigation of atmospheric aerosol optical properties over Lake Taihu using MODIS and CE318 data

Abstract

Aerosol model is a major obstacle for passive remote sensing of aerosol properties. For the continent or urban aerosol model does not fit the needs for more accurate retrieval, and the user defined aerosol model may be more near to the realistic condition in Taihu region. A method has been developed for retrieving the aerosol model and optical properties including polarization, i.e., scattering coefficient, asymmetry factor, single scattering albedo, scattering phase function and polar phase function. In Lake Taihu, the study area of our two combined remote sensing observations in the winter and summer 2006, we got water surface spectral data of ASD (Analytical Spectral Devices) by the ship, atmospheric data of CE318 sunphotometer on the shore, and the MODIS (Moderate Resolution Imaging Spcectroradiometer) image data on the TERRA Satellite. By using the nearly synchronous measurements of the data from surface spectrum and the sunphotometer with the image, and by use of the radiative transfer model 6S(Second Simulation of a Satellite Signal in the Solar Spectrum), varying the components of the aerosol type, a LUT (look up table) is made for the radiance on the satellite. When the total relative error of the new defined parameter for relative error is getting to the least, the aerosol type will be decided. Then, based on the determination of aerosol model, the atmospheric aerosol properties over Lake Taihu have been computed by using Mie theory and analyzed with the typical continental and urban aerosol models available in 6S. These results show that the user-defined aerosol model is a mix model of continent and urban which corresponds with previous studies. Moreover, they may be useful for resolving the vector RTE (radiative transfer equation). In this paper we tried to provide a method with the combination of remote sensing data to obtain the optical properties of atmospheric aerosol over inland water in different seasons. We respect it will be helpful for accurate atmospheric correction in the future.