A technique for the calibration of hydraulic models using uncertain satellite observations of flood extent

摘要

This paper presents a methodology to calibrate hydraulic models using possibilityof inundation maps derived from satellite imagery. The study was performed on a river reach of the Lower Dee, UK, where a coarse resolution image(ENVISAT ASAR) and high resolution satellite image (ERS-2 SAR) were acquired at the same time during the December 2006 flood event. Ten different flood extent maps were derived from the two flood images by using five different procedures to process these data. These flood extent maps were used to perform a sensitivity analysis of a simple raster-based inundation model (LlSFLOOD- FP). The sensitivityanalysisenabled us to investigatethe capability of the two different resolution images to calibrate the friction parameters of the flood inundation model. The analysis showed that the optimal parameters of the modeldepend on the type of satellite image used to evaluate the modelas well as on the particular procedure used to derive the flood extent map. Finally, the study developeda novel methodology to calibrate flood inundation models by comparing the model results to a possibility of inundation map obtained by combining the ten different flood extent maps.