Simultaneous determination of aerosol optical thickness and water leaving radiance from multispectral measurements in coastal waters
Dr. SHI Chong（石崇 ）
Retrieval of aerosol optical thickness (AOT) and water leaving radiance over ocean is challenging since the latter mostly accounts for ~10% of the satellite observed signal and can be easily influenced by the atmospheric scattering. Such an effort would be more difficult in turbid waters due to the existence of optically complex oceanic substances or high aerosol loading. Standard atmospheric correction schemes, such as the ones implemented in the MODIS instrument, use near infrared or shortwave infrared bands to retrieve AOT based on the assumption of null water leaving radiance and then extrapolate to the shorter bands using the derived aerosol modes from look up tables. However, the retrieved aerosol spectral properties are not always fully consistent with the observations at shorter wavelengths as a result that the AOT values are sometimes reported to be overestimated and the derived water leaving radiance is occasionally negative in those bands. In this talk, I will introduce our recent work related to the development of a new algorithm for the simultaneous determination of AOT and water leaving radiance from multi-spectral measurements based on an optimal estimation approach; an oceanic radiative transfer model for open or turbid waters; an acceleration scheme for the radiative transfer model from Neutral Network method.