HR: 0800h
AN: A51A-0745    [Abstracts]
TI: Seasonal Difference of Air Parcels Arriving at the Japan Area Between Summer and Winter
AU: * Kazaoka, R
EM: kazaoka@kugi.kyoto-u.ac.jp
AF: Department of Geophysics, Kyoto University, Sakyo-ku, Kyoto, 606-8502 Japan
AU: Kida, H
EM: kida@kugi.kyoto-u.ac.jp
AF: Department of Geophysics, Kyoto University, Sakyo-ku, Kyoto, 606-8502 Japan
AB: General increase in atmospheric air pollutants from Eastern Asia is expected to continue in the near future. Since anthropogenic and natural aerosols are widely distributed around the Japan area and the interannual and seasonal variability occurred, it is important to examine source and transport pathway of continental and marine air mass arriving at the Japan area. Examining probability distribution of transport pathway of the air parcels arriving at the Japan area, relationship between atmospheric circulation and the source and transport pathway of the air parcels were investigated. In this study, air parcel's trajectories were calculated using wind fields in sigma coordinate. The seven day backward air parcel's trajectories arriving at two areas, which are south (32.5N, 131.0E) and north of Japan (43.5N, 142.5E) in boundary layer, were calculated each day from January to December 2001. The probability of transport pathway was estimated by counting the trajectories in 2.5 degrees longitude-latitude columns at a grid. The grid point values of geopotential height and wind component from the NCEP/DOE AMIP-II re-analysis data were used. It was found out that the probability distribution of transport pathway of air parcels arriving at those areas was changed with season. The source and transport pathway of air parcel arriving at those areas were greatly different especially in summer and winter, although the south of Japan is close to the north of Japan in the global scale. In winter the south of Japan was strongly influenced by continental air mass from the Eurasia. However, the marine air mass from the Sea of Okhotsk and near Alaska was frequently transported toward the north of Japan. In winter, passage of extratropical cyclone around the Japan area, effluent of Siberian anticyclone, and development of the extratropical cyclone over the Okhotsk Sea played important roles in transport of air parcel arriving at the Japan Area. In summer, transport of marine air mass from East China Sea and Pacific Ocean toward the south of Japan was prevailed, although continental air mass from the east coast of Asian continent including Japan and Korea were often transported to the north of Japan. It was found out that the features of air parcel transport in summer were associated with activity of the Pacific high and weak westerly flow around the Japan area. It is suggested from these findings that the knowledge of geographical location of a specified area is important when we examine the transport mechanism on the atmospheric circulation system.
DE: 3319 General circulation
DE: 1610 Atmosphere (0315, 0325)
DE: 0300 ATMOSPHERIC COMPOSITION AND STRUCTURE
DE: 0322 Constituent sources and sinks
DE: 0368 Troposphere--constituent transport and chemistry
SC: Atmospheric Sciences [A]
MN: 2004 AGU Fall Meeting