A model-based approach for mapping floods using Cosmo-SkyMed data

The COSMO-SkyMed mission offers a unique opportunity to obtain radar images useful for flood mapping, being characterized by high revisit time, thanks to the four satellites that form its constellation. To study the potentiality of Cosmo-SkyMed radar data for this purpose, two inundation events are analyzed in this paper, namely the flood occurred in Myanmar in May 2008 and the event that took place in the city of Alessandria (Northern Italy) in April 2009. For the first event, two radar images were considered, one temporally close to the peak of the event, and the other one that was acquired one week later. As for the Alessandria overflow, a time series of images was available. While most of the literature algorithms are based on fixed thresholds applied on an image temporarily close to the event, our method accounts both for specular reflection, typical bare flooded soils, and for double bounce backscattering often occurring on forested and urban inundated areas. Such a model-based approach is expected to improve the accuracy of flood mapping.