Validity of SeaDAS water constituents retrieval algorithms in Australian tropical coastal waters

Abstract

This paper reports an assessment of the performance of the seven global empirical and semi‐analytical chlorophyll and bulk IOP retrieval algorithms implemented in SeaDAS, for the local conditions in tropical waters off the Australian northeast coast. An approach based on radiative transfer simulations was used providing systematic assessments. The study shows that when coloured dissolved organic matter (CDOM) and non‐algal particle (NAP) concentrations are low, the seven algorithms tested, as expected, can retrieve chlorophyll with an error of, at best, 75% for 80–90% of the cases. The accuracy generally degrades rapidly with increasing CDOM and NAP concentrations. For the semi‐analytical algorithms (bulk IOP retrieval enabled), the QAA algorithm achieved a better result at retrieving the total absorption, a, backscattering, bb and backscattering by particles, bbp. However, none of the algorithms can break down the total absorption into components with reasonable accuracy. The study indicates that without incorporating regional and seasonal knowledge of specific IOPs the accuracy in water constituent retrievals from remote sensing is poor, hindering the use of remote sensing in water quality management.