3d Flood Information from Sar as a Means for Reducing Uncertainties in Flood Inundation Modeling
نویسندگان
چکیده
SAR images of river inundation prove to be very relevant for operational flood management. However, common exploitation of satellite images of floods is generally restricted to a flood extent extraction. The usefulness of these images could be significantly improved by providing a hydraulic-coherent 3-dimensional (3D) characterization of floods and by integrating these Remote Sensing-Derived (RSD) spatial characteristics of floods in hydraulic models in order to render flood inundation forecasts more reliable and accurate. This study aims at developing SAR image analysis methods that go beyond flood extent mapping in order to demonstrate the potential of these images in the spatio-temporal characterization of flood events. To fulfill this objective, two research issues were addressed. The first issue relates to water level estimation. Applied to an ENVISAT image of an Alzette River flood (2003, Grand-Duchy of Luxembourg), the developed method provides ± 54 cm average vertical uncertainty water levels, that were validated with ground surveyed high water marks. The second issue aims at evaluating how far RSD flood characteristics could allow a better constraining of hydraulic models. To achieve this goal, various calibration scenarii using only recorded hydrographs or recorded hydrographs and RSD flood characteristics are computed. These scenarii show that the integration of the RSD characteristics leads to better constrain the model (i.e. the number of parameter sets providing acceptable results with respect to observations is reduced) and render it more reliable, even in the case of quite rather abundant ground observed data.
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