1. Department of Solar Energy and Environmental Physics, Jacob Blaustein Institute for Desert Research, Ben-Gurion University of the Negev, Sede-Boker Campus 84990, Israel and Department of Physics, Ben-Gurion University, Beer Sheva 84105 Israel
2. Department of Natural Resources and Environmental Management, Faculty of Social Sciences, University of Haifa, Mount Carmel, Haifa, 31905 Israel, Israel