MESOSCALE MODELING OF RUNOFF AND WATER BALANCES USING REMOTE-SENSING AND OTHER GIS DATA

For about two decades remote sensing (RS) data in the form of multi-spectral air photography, ground based weather radar as well as geostationary and polar orbiting satellite data have been available for use in hydrology. It is the intention of this paper to advocate the use of RS data in the field of hydrological modelling. It is shown that the main field of application of RS data in hydrological modelling lies in the meso-scale. The potential of RS in the framework of GIS is shown along with three examples. The first example shows the use of RS data for rainfall/runoff modelling in the lower meso-scale. A model was developed which used the high spatial resolution of Landsat polar orbiting satellites (30m X 30m) for model parameter estimation. The second example shows the use of geostationary satellite data for the computation of long time series of monthly runoff values in the upper meso-scale. It was applied in West Africa for the purpose of water resources planning. In the third example, a water balance model in the upper meso-scale is presented which computes daily values for all the variables in the water balance equation along with an example of the model's application in the international Mosel River basin. Here also the detection of land use changes by multi-temporal satellite imagery and their impact on hydrological parameters is discussed. In this example, emphasis is put on the combination of RS data with other information, such as digital elevation models or digitized maps, all within the framework of GIS. In conclusion, not only the potential but also the limitations of the use of RS in hydrological modelling are discussed.