Remote sensing of ocean colour: Accuracy assessment of an approximate atmospheric correction method

Abstract

The accuracy of an approximate atmospheric correction method included in a processing scheme for SeaWiFS images, is assessed for atmospheric and water parameters typical of midlatitude European sites with specific reference to the North Adriatic sea. The analysis is carried out using a highly accurate numerical radiative transfer code and results show that the coupling of an approximate atmospheric correction method with vicarious calibration of the space sensor is a valuable solution for the estimate of atmospheric and seawater parameters. Over different simulated measurement conditions, the aerosol optical thickness at 865 nm and the aerosol @ngström exponent are estimated with uncertainties lower than - 5% and - 8% respectively. The uncertainty in water leaving radiance estimate decreases on pigment concentration increase and on yellow substance absorption decrease. For medium-high pigment concentration (i.e. 3.0-10.0 mg m m 3 ) and for a medium yellow substance absorption (i.e. a ys (400 nm) = 0.149 m m 1 ), the water leaving radiance is estimated with an average uncertainty of - 10%. The remote sensing reflectance ratio R 35 is estimated with an average uncertainty ranging between m 5% and +1%.