<title>Removal of atmospheric effects from hyperspectral imaging data for remote sensing of coastal waters</title>

Abstract

Existing atmospheric correction algorithms for multi-channel remote sensing of ocean color from space were designed for retrieving water leaving radiances in the visible over clear deep ocean areas. The information about atmospheric aerosols is derived from channels between 0.66 and 0.87 micrometer, where the water leaving radiances are close to zero. The derived aerosol information is extrapolated back to the visible when retrieving water leaving radiances from remotely sensed data. For the turbid coastal environment, the water leaving radiances from the 0.66-micrometer channel may not be close to zero because of back scattering by suspended materials in the water. This channel may not be useful for deriving information on atmospheric aerosols. As a result, the algorithms developed for applications to clear ocean waters cannot be easily modified to retrieve water leaving radiances from remotely sensed data measured over the coastal environments. We have developed an atmospheric correction algorithm for hyperspectral remote sensing of ocean color with the near-future Coastal Ocean Imaging Spectrometer (COIS). The algorithm uses lookup tables generated with a vector radiative transfer code. Aerosol parameters are determined by a spectrum-matching technique utilizing channels located at wavelengths longer than 0.86 micrometer. The aerosol information is extracted back to the visible based on aerosol models during our retrieval of water leaving radiances. Quite reasonable results have been obtained when applying our algorithm to process hyperspectral imaging data acquired with an airborne imaging spectrometer.