Mapping of sea bottom topography in a multi sensor approach

Three remote sensing methods for obtaining information on sea bottom topography have been investigated: passive optical bathymetry, sun glint observation and radar observation. Optical and microwave remotely sensed data as well as extensive in-situ data, including a detailed bathymetric map, were gathered in a sand wave area off the Dutch coast. These data were compared with each other and with model predictions. The models are based on the current state-of-the-art, with some extensions. Passive optical bathymetry has limited use above the North Sea because of its limited depth range. Sun glint observation of bottom topography is possible, but its practical applicability is limited by the requirement of low wind speeds and cloudless weather. Radar observation with an imaging radar operating at long wavelengths has the highest potential. The agreement between radar data and model predictions is not always good, due to lack of knowledge on the basic processes. However, in cases where there is good agreement, the imaging model can be inverted numerically to retrieve depth information from radar images