佐久盆地の局地風と大気汚染

Abstract

High concentrations of photo-chemical oxidants are frequently observed in summer in theSaku Basin, in Nagano prefecture, where there is no large-scale source of air pollutions. Airpollutions in the Saku Basin are caused by long-range transport of air pollutants from coastalareas with easterly wind of regional scale. The purpose of this paper is to clarify the localwind system such as mountain and valley wind, and estimate the exchange of pollutantsbetween the atmospheric boundary layer and the free atmospheric layer in the Saku Basin.Field observations of the vertical distributions of wind, temperature, ozone concentrationand so on were carried out at Komoro, Saku, Asashina in the Saku Basin from 23 to 25 inJuly 1985.Amounts of ozone fluxs and horizontal divergence of air over the Saku Basin werecalculated. Preliminary estimates indicated that the half amount of ozone transported fromcoastal areas were lifted into the above free atmospheric layer over the Saku Basin and theremainder were transported to the westerly inland area.