Quantitative use of passive optical remote sensing over coastal and inland water bodies

Adequate water quality management requires information on actual concentrations, spatial distribution and temporal variations of water constituents. Using passive remote sensing, synoptic information on a limited number of water parameters can regularly be obtained. Monitoring purposes and the study of the functioning of the aquatic ecosystem require quantitative processing and analysis rather than visual interpretation of remote sensing imagery. The quantitative use of remote sensing over water bodies is hampered by insufficient understanding of the physical mechanisms involved and by technical limitations of the instruments used. Items that play an important role in this respect are connected to the object characteristics, the geometry of the Sun, object and sensor, the atmosphere, the remote sensing instruments and the data processing involved. These items are critically assessed successively. Practical solutions and recommendations concerning implementation of remote sensing in operational water management practice are given.