Centre de ressources numériques
Bathymetry;coastal zone;diffuse attenuation;lagoon;MERIS
An estimation of bathymetry in the optically complex lagoon of New Caledonia was performed from multispectral satellite images. Bathymetric estimation was obtained with Medium Resolution Imaging Spectrometer (MERIS) images acquired at different dates. The method is based on the rotation of a pair of spectral bands (red and green bands). One of the resulting images is only depth-dependent when the other is reflectance-dependent. A comparison was made with a compilation of bathymetric data from Institut de Recherche pour le Developpement (IRD) Noumea measurements. This study shows the influence of the variation of water composition, and then of the diffuse attenuation, on bathymetric results. The variation of chlorophyll concentration, correlated with variation of diffuse attenuation, explains the error of the estimation map. The results show that this method remains valid under a low (<1 mg . m(-3)) and constant concentration (<10% of variation) of chlorophyll to limit the variation of RMSE in the image on the bathymetric estimation (<15.5%).