Areal distribution of water-insoluble particles in snow covers of the central mountainous area, Japan

The vertical snow samples collected from 6 locations (Iou-zen: 800m A.M.S.L; the nearest site from the Sea of Japan, Kongoudou-zan: 1300m, Nishi-Hodaka-Dake: 2200m; the Northern Japan Alps, Hachimori-yama: 2100m, Kiriga-mine: 2000m, Yatsuga-take: 2200m; the most inlying site) in the central mountainous area, Japan, during early spring season 2004, were analyzed for size-separated concentrations of water-insoluble particles in snow layers to investigation of long-range transportation of chemical substances from the Asian continent to high mountainous areas in Japan. Most of particles are less than 30 μm in diameter, the greater part of particles observed at the 6 locations were considered to be transported from the Asian continent sources as Asian dust (KOSA). The variation patterns of the vertical profiles of particle concentrations in snow layers were corresponding among each location. The concentrations of particles with less than 30 μm was gradually increased with increasing distance from the Sea of Japan to the Japan Alps, although, sharply-decreased at 3 sites located the monsoon-leeward of the Japan Alps, suggesting that the particles transported with monsoon were gradually removed from air and deposited in snow cover when the air parcel pass through the Japan Alps.