"AN ESTIMATION OF THE DISTRIBUTION OF THE AMOUNT OF FOG WATER DEPOSITION OVER THE KANTO-CHUBU AREA" 

Kazuya Inoue¹, Haruyuki Higashino¹, Ryusuke Yasuda², Arimitsu Ikeda²

¹National Institute of Advanced Industrial Science and Technology
²Osaka Prefecture University

8th International Conference for Atmospheric Sciences and Applications to Air Quality (Tsukuba, Japan 2003/3/13)

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Abstract

Fog water deposition is one of the most important pathways of the deposition of atmospheric pollutants as well as wet and dry deposition. It is necessary to estimate the distribution of the deposition of polluted fog water in order to define the relationship between atmospheric pollutants and the forest decline. In Japan, however, there were few observational studies about fog water deposition.

We tried estimating the regional distribution of the amount of fog water deposition itself by means of numerical simulation, constructing the on-line coupled meteorological fog deposition model. The Regional Atmospheric Modeling System (RAMS) was utilized as a meteorological model, and the model which had multi layers in the forest canopy was utilized as a fog water deposition model. The target region was the Kanto-Chubu area including the northern Kanto mountainous area where the forest was declined significantly. 

At first, we investigated the typical meteorological condition favorable for the occurrence of fog in the northern Kanto mountainous area, and found that fog occurred frequently when local circulation such as ‘extended sea breeze’ developed and water vapor was transported to inland regions. Next, on such a meteorological condition, we conducted numerical simulations to investigate the typical regional distribution of the amount of fog water deposition. 

It was found that fog water was deposited in many places over inland mountainous and valley regions and that especially much fog water (i.e. more than 10 mm/day) was deposited over the mountainous area surrounding the Oku-Nikko area where the forest decline was especially significant. This result suggests that fog water deposition has some impacts on the forest decline in the mountainous area.

Keywords

fog, deposition, RAMS, simulation, Kanto