Vol. 7, No. 2, 105-119, 2008

Abstract
Remote sensing techniques are applied to map submerged vegetation in coastal zones and lagoon environments. The lack of spectral signatures of submerged vegetation measured in situ and the uncertainties in water column attenuation characteristics often restrict the use of classification algorithms. In this paper, processing techniques for field measurements of spectral radiance on submerged vegetation are discussed and applied to show the usefulness and limits of this method for submerged vegetation mapping in shallow areas. A field campaign was carried out to quantify the spectral transparencies of two contrasting water bodies, measuring underwater downwelling irradiance at different depths. An accurate computation of the diffuse attenuation coefficient is therefore important; this study has shown that these are readily obtainable using in situ measurements of spectral irradiance. Our results show that spectral signatures for seagrass canopies can be derived from in situ measurements of spectral radiance. Although the spectral signature of the submerged vegetation is expected to vary with phenological period, a result of this research was the determination of typical spectral signatures of some of the most important Mediterranean submerged vegetation, during the most favourable period for optical remote sensing acquisitions.

ISSN 1729-3782