Guerriero, L.

The COSMO-SkyMed mission offers a unique opportunity to obtain radar data characterized by short revisit time, thus being useful for flood evolution mapping. A procedure to monitor an inundation event using multitemporal COSMO-SkyMed data is presented in this paper. The methodology is based on an automatic image segmentation technique and on the use of a well-established electromagnetic model to correctly explain the radar return from the image segments. It is applied to a series of five COSMO-SkyMed images regarding an event chosen as a test bed, i.e., a flood occurred in Northern Italy in 2009. In order to associate the segments to the classes of flooded or non-flooded areas, some reference multi-temporal backscattering trends have been assumed with the aid of the theoretical model. Using these reference trends as a training set, a classification algorithm has been developed to generate a map of the flood evolution. Although the methodology needs to be further tested on different case studies, our investigation demonstrates the feasibility and the utility of a combined use of an electromagnetic scattering model and an advanced image processing technique for inundation monitoring.

An algorithm developed to map flooded areas from synthetic aperture radar imagery is presented in this paper. It is conceived to be inserted in the operational flood management system of the Italian Civil Protection and can be used in an almost automatic mode or in an interactive mode, depending on the user’s needs. The approach is based on the fuzzy logic that is used to integrate theoretical knowledge about the radar return from inundated areas taken into account by means of three electromagnetic scattering models, with simple hydraulic considerations and contextual information. This integration aims at allowing a user to cope with situations, such as the presence of vegetation in the flooded area, in which inundation mapping from satellite radars represents a difficult task. The algorithm is designed to work with radar data at L, C, and X frequency bands and employs also ancillary data, such as a land cover map and a digital elevation model. The flood mapping procedure is tested on an inundation that occurred in Albania on January 2010 using COSMO-SkyMed very high resolution X-band SAR data.