Flood mapping in vegetated and urban areas and other challenges: Models and methods

Floods are the most frequent weather disasters in the world and the most costly in terms of economic losses. Mapping flood extension is fundamental to ascertain the damage and for relief organization. Spaceborne synthetic aperture radar (SAR) systems represent a powerful tool to monitor floods because of their all-weather capability, the very high spatial resolution of the new generation of instruments, and the short revisit time of the present and future satellite constellations. However, mapping flooded vegetated and urban areas still represents a challenging problem. Modeling different targets both in the presence and in the absence of flood water is a very complex task. In the first part of the chapter we review these challenging conditions, showing their potential effects on radar data and in particular on COSMO-SkyMed images. In some cases the potential of electromagnetic models to predict the radar response is shown. A second part of the chapter illustrates a number of strategies one can exploit, with examples showing the achievable performances with respect to a simple mapping of dark areas in the SAR image.