GOCI-II atmospheric correction algorithm and its initial validation

Abstract

We describe the atmospheric correction algorithm and its initial validation results for the second Geostationary Ocean Color Imager (GOCI-II), which is the successor to the Geostationary Ocean Color Imager (GOCI). Atmospheric correction is a fundamental process in ocean color remote sensing that derives the water reflectance at the sea surface from the top-of-atmosphere. The GOCI-II atmospheric correction method is theoretically based on the previous GOCI atmospheric correction, then partially improved accuracy for turbid waters with the GOCI-II's two additional 620 and 709 nm bands. The GOCI-II's vicarious gains are adjusted with the remote-sensing reflectance dataset derived from the VIIRS dataset to enhance the accuracy over clear waters. The match-up showed an acceptable result, with the mean absolute percentage errors are fall within 5% in blue bands. It is supposed that part of the deviation over case-II waters arose from a lack of near-infrared vicarious calibration. We expect the GOCI-II atmospheric correction algorithm to be improved and updated regularly to the GOCI-II data processing system through continuous calibration and validation activities.