Seasonal variations of atmospheric trajectories arriving at Osaka in the Kansai area

Seasonal characteristics of back trajectories of long-range pollutants beyond 100 km from the ground are studied for the Kansai area of Japan from the climatological point of view. The wind fields in the domain being considered are first determined by a mass-consistent model and then trajectories of pollutants terminating the central urban area of Osaka are estimated using these wind fields. The results shows that routes of back trajectories are primarily determined by synoptic-scale pressure distributions and the topographic feature.