1. Institute of Applied Physics “N. Carrara,” National Research Council, Sesto Fiorentino, Italy
2. Byrd Polar and Climate Research Center, The Ohio State University, Columbus, OH, USA
3. ElectroScience Laboratory, The Ohio State University, Columbus, OH, USA
4. Department of Electrical Engineering and Computer Science, Radiation Laboratory, University of Michigan, Ann Arbor, MI, USA
5. Department of Geography and Earth and Environmental Systems Institute, Pennsylvania State University, University Park, PA, USA