THE USE OF MICROWAVE REMOTE-SENSING TO IMPROVE SPATIAL PARAMETERIZATION OF HYDROLOGICAL MODELS

In the past, cloud-cover has been a major factor limiting the use of remote sensing for hydrological applications. Satellites such as ERS-1, which carry microwave sensors, can now achieve regular observation of the Earth's surface, even in the presence of thick cloud-cover. This offers new opportunities for the observation of hydrological change over time and for the quantification from space of hydrological variabilities which are very difficult to measure on the ground. This paper identifies three areas where remote sensing can be particularly useful for hydrological studies. These are, the siting of ground-based instruments, the measurement of catchment physical characteristics and the quantification of catchment variables, Application areas for microwave remote sensing are then classified as being either operationally feasible, near-operational or requiring development and/or multifrequency sensors. A range of satellite microwave sensors will be operational until the end of the century; their data will be underused unless hydrological models are designed to accept the type of spatially referenced information they produce.