1. Department of Earth and Environmental Sciences, Remote Sensing of Environmental Dynamics Laboratory, Università degli studi di Milano - Bicocca, Milan, Italy
2. Institute for Electromagnetic Sensing of the Environment, National Research Council, Milan, Italy
3. Environmental Protection Agency of Umbria Region, ARPA Umbria, Terni, Italy
4. Environmental Protection Agency of Umbria Region, ARPA Umbria, Perugia, Italy