Altimetric data in hydrological models
Frederique Seyler(1) , Stephane Calmant(1) , Marie Paule Bonnet(1) , Juan Gabriel Leon(1) , Frederic Frappart(2) , Mathilde Cauhope(1) , naziano Filizola(3) , and Jean Loup Guyot(1)
14 av E. Belin,
(2) CNES, 14 AV. E. Belin, 31400 Toulouse, France
(3) Univ. Manaus, Univ. manaus, Manaus, Brazil
Hydrodynamical models are aimed to describe the flow propagation in river channels. Such models are highly demanding in data input, including water height, channel geometry (cross-sections and bed slope). In large basin such as the Amazon, the hydrodynamical modelling was coming up against such a need of data. Above all the lack of gauge levelling and the scarcity (relatively to the size of the basin) of the gauging stations have precluded until now the modelling in most of the network contributors. In the Amazon, another drawback is the un-channelized flow, derived in numerous and large inundation plains.
Satellite altimetry data can solve part of these problems. First, for gauge levelling, we present some examples of stations that we levelled using various satellite data, T/P, ENVISAT and ICEsat. We discuss the accuracy of the method, by comparation with GPS levelling. Second, we used the slope derived from these levelling to run a model based on diffusion-cum-cinematic wave propagation (Muskingum-Cunge formulation). Third, we have combined the modelled discharge with altimetric heights to produce rating curves at satellite-river crossings.
Concerning the inundation plains, altimetric data are not, as are the gauging stations, limited to channelized rivers. Thus, it is possible, by combining the water elevation variations from various radar altimetric data sources with the inundation spatial extension mapping from radar images as the JERS mosaic, to quantify the volume variation of water storage in the inundation area. These estimation are very useful for hydrodynamical modelling of the exchanges between the river channel and the floddplain.