1. a Department of Physics , Bar-Ilan University , Tel-Aviv , Israel
2. b Katif Research Centre for the Development of Coastal Deserts , Beit-Kama , Israel
3. c Department of Geography and Environmental Development , Ben Gurion University of the Negev , Beer-Sheva , Israel
4. d Jacob Blaustein Institute for Desert Research , Ben Gurion University of the Negev , Beer-Sheva , Israel