Operational applications of remote sensing in hydrology: success, prospects and problems

The use of remote sensing information in operational hydrology is relativel y limited, but specific examples can be cited for determining precipitation , soil moisture, groundwater, snow, surface water and basin characteristics . The application of remote sensing in hydrology can be termed operational if at least one of two conditions are met: (a) the application produces an output on a regular basis, or (b) the remote sensing data are used regularl y on a continuing basis as part of a procedure to solve a problem or make d ecisions. When surveying the various operational applications, simple appro aches and simple remote sensing data sets are the most successful. In the d ata-sparse developing countries, many operational remote sensing approaches exist (out of necessity) that may not be needed in developed countries bec ause of existing data networks. To increase the use of remote sensing in op erational hydrology in developed countries, pilot projects need to be incre ased and information services must be improved. Increased utilization of GI S to combine remote sensing with other information will promote new product s and applications. End user training must be improved by focusing on satel lite data processing and manipulation. In developing countries the same imp rovements are needed plus some more basic ones. There is a need for interna tional monetary assistance to establish long-term remote sensing data, impr oved database systems and image processing capabilities. There is also the need to set up innovative regional training centres throughout the developi ng world.