Abstract
Empirical bio-optical algorithms developed for GLI are described. These algorithms can be used to retrieve in-water properties from GLI normalized water leaving radiances in temperate Case 1 waters. The OC4 Chl-a algorithm uses the maximum band ratio switching procedure for bands that do not saturate over the ocean. GLI is the only ocean color sensor that has ultra-violet (UV) bands and we developed an experimental red tide UV index for the early detection of dinoflagellate blooms. The red tide index uses the increased absorption of UV light by mycosporine-like amino-acids (MAAs). A special version of the Chl-a algorithm was developed for the Southern Ocean Case 1 waters. The standard algorithms cannot be applied to turbid near-shore waters, e.g. off Korea and Hong Kong where bio-optical characteristics deviate drastically from Case 1 characteristics. Developing new and improved algorithms for Case 2 waters is a major challenge in bio-optical oceanography.
