Aircraft Measurements of Medium-Range Transport of Air Pollutants over Complex Terrain

Abstract

A series of aircraft measurements of the three-dimensional distribution of air pollutants and meteorological elements was conducted each summer of 1980, 1981 and 1982 in the Inland Sea area of Japan in order to examine the medium-range transport processes due to local circulations.The data show that polluted air is horizontally distributed over almost all of the Sea and is confined to levels below 1000m in the early morning. The polluted air is transported to upper levels up to 3000m in the evening by upslope winds and/or the sea breeze on the Shikoku side of the Sea. Developed cumulus clouds over the mountains seem to contribute to the vertical transport of ozone and the scavenging of aerosols.The structure of the internal boundary layers formed over the complex terrain is also analyzed. The results agree quite well with a simple model simulation.