A new combined atmospheric correction algorithm for GOCI-2 Data over coastal waters assessed by long-term satellite ocean color platforms

Abstract

ABSTRACT Accurate atmospheric correction (AC) is essential in retrieving ocean and coastal water ecosystem products from ocean colour remote sensing data. Generally, the atmospheric correction algorithms that are based on Near Infrared (NIR) bands are effective in clear water, whereas the algorithm based on ultraviolet (UV) bands deliver accurate results in turbid water. A practical approach is to employ a UV-NIR combined algorithm that uses both UV and NIR bands for clear and turbid water, respectively. However, currently, the UV-NIR algorithm generates a data discontinuity pattern when a single threshold value is used, as the coastal water exhibits a continuous variability between clear and turbid states. To address this issue, we propose a ‘clear and turbid water transition evenly combination’ algorithm that utilizes UV and NIR bands of the Second Geostationary Ocean Colour Imager (GOCI-2). We evaluated the new algorithm’s performance by comparing GOCI-2 images with in-situ data, and the results showed good agreement between the retrieved Remote Sensing Reflectance ( R rs ) values at visible bands and the in-situ observations. The new AC algorithm can achieve better precision, with Mean Absolute Percentage Difference (MAPD) reduced by 6.6 95.3% and 5.2 18.9% compared with UV AC and the standard AC algorithm employed by the Korea Ocean Satellite Center (KOSC).