Ambiguities in the inversion of the Ocean Colour: Problems and Solutions

Abstract

The inverse problem of ocean colour consists in deriving the inherent optical properties (IOP) of marine particles from a reflectance spectrum measured at the sea surface. Such a problem is ill-posed or ambiguous because of the non-uniqueness of the solution; i.e. several combinations ofIOP values can lead to a unique reflectance spectrum. Currently, great efforts are made in the development of inverse methods to accurately retrieve the IOP. However, much less studies have been devoted to the analysis of the ambiguities, which affect yet the error on the IOP retrieval. In this paper, a set a measures suitable to characterized the ambiguities of an inverse problem are introduced and used to describe the ocean colour problem. The ambiguities of the IOP retrieval are evaluated and their implications for inverse modelling are studied. Finally, different strategies to reduce the effects of ambiguities are discussed