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RWE Dea Azerbaijan tasked GAF with the performance of a bathymetric survey in its exploration area of interest in the Caspian Sea. GAF made use of satellite remote sensing and its new stereo approach for this task and mapped an area of 230 sqkm. The bathymetric analysis was based on a stereo pair of very high resolution multispectral satellite images. First, stereoscopic measurements were performed, which provided depth information about clearly recognisable submerged features and topography. In a second step, a bathymetric model was created using these features and the satellite imagery, in order to provide area-wide bathymetric mapping of depths and seabed morphology. The bathymetric information was collected in a regular grid with a spatial resolution of 4m and had an absolute vertical accuracy better than 2m. The modelling approach utilises the spectral absorption of light in the water column, which is dependent on the water depth. The method is based on the amount of light penetration into the water column, which under favourable circumstances can reach depths of up to 20m. It should be noted, however, that strong sun glint, and dense accumulations of microorganisms, vegetation or suspended load can hamper the application of the method.

Dr. Christian Bücker, Manager of Geoinformation Research and Development at RWE Dea, states: "The satellite-derived bathymetry provides valuable information for our exploration block in our area of interest in the Caspian sea. The bathymetric analysis was performed successfully and has sufficient accuracy to detect and map mud volcanoes. The existing sparse bathymetry knowledge of the areas has thus been greatly improved."

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