Correction of artifacts in the SeaWiFS atmospheric correction: removing discontinuity in the derived products

Abstract

It has been found that, at the certain solar and sensor-viewing geometry and for certain atmosphere conditions, discontinuity lines appear in the Sea-viewing Wide Field-of-view Sensor (SeaWiFS) retrieved atmospheric and ocean color products. Such discontinuity lines, which do not happen very often, are apparently artifacts from the atmospheric correction scheme that uses the lookup tables to process SeaWiFS data. In this paper, a brief description of the SeaWiFS atmospheric correction algorithm, in particular, the technique that is used in retrieving the aerosol models and aerosol radiance contributions in the visible wavelengths, is provided. Results from some specific simulations that explain the causes of the discontinuity lines in the derived products are presented. We show that these discontinuities appearing in the derived SeaWiFS products are the result of the atmospheric correction due to aerosol model effects. To remove the discontinuities, a simple modification to the current atmospheric correction algorithm is proposed and tested with both simulated and real SeaWiFS data. The modification has been implemented in the SeaWiFS fourth data reprocessing in August 2002.