Numerical study of fog occurrence and fog water deposition on the vegetation at a semi-arid coastal area in Saudi Arabia

Katata, Genki; Nagai, Haruyasu  ; Ueda, Hiromasa*

Generation of fog along the coastal mountain range in a semi-arid environment is investigated using three-dimensional Mesoscale Model (MM5) simulations. The study focuses on dense fog formed along a west side of the Asir mountains in Saudi Arabia during January 2002. MM5 reproduced tower measurements of cloud water content, wind speed and direction, air temperature, humidity, and solar radiation. Computed profiles of wind speed and direction, air temperature, and humidity also agreed with rawinsonde measurements. Numerical experiments using a one-dimensional model for atmosphere-soil-vegetation interaction (SOLVEG) with fog water deposition process have been performed to evaluate the contribution of fog water deposition to water resource at the area. Meteorological and cloud water at the lowest atmospheric layer from MM5 simulation results were used in the experiments. Fog along the coastal mountain range may be an important water resource for vegetation surviving in the area.