1. Department of Engineering, University of Perugia, via G. Duranti 93, 06125 Perugia, Italy
2. Department of Information Engineering, Electronics and Telecommunications, Sapienza University of Rome, via Eudossiana 18, 00184 Roma, Italy
3. Institute of Biometeorology (IBIMET—CNR), via G. Caproni 8, 50145 Firenze, Italy