Contribution of multispectral satellite imagery to the bathymetric analysis of coastal sea bottom

Abstract

The knowledge of the topography of the seafloor is important for several applications. Image satellites of observation of the earth are the result of the interaction of the electromagnetic radiance with the system sea - atmosphere and sensor. To understand this complex phenomena us developed an analytic model of radiatif transfer simulation in water coupled to an atmospheric model in order to simulate measure by satellite. This direct model permits to follow the solar radiance in his trajectory Sun-Atmosphere - Sea - Depth of sea- sensor. The goal of this simulation is to show for every satellite of observation (Alsat1, Spot, Landsat MSS, Landsat TM) possibilities that can offer in domain of bathymetry. The principle of measure of bathymetry necessarily takes this model of reflectance joining the intensity of radiometric signal measured by the satellite to the depth as a basis; it can call on the physical method that requires the knowledge of all parameters governing this model (optic properties of water, coefficient of reflection of the bottom, transmittance of the atmosphere,). In application, a set of relations figures are gotten to determine the bathymetry of an inshore zone of Algeria. The model provides of image mono channel where each pixel of the maritime domain is represented either by a radiometry in - situ but rather by a calculated depth. In general the use of hybrid multiple Spot band regression algorithms are superior to the exclusive use of any single band.