関東地方における酸性降下物の分布特性及びその輸送メカニズムに関する解析

抄録

The value of acidity in Japan vary widely from the seasons. It is considered that acidic oxide in the Kanto region of Japan is mainly caused by the advection from the East-Asia continent in winter. In summer, it may be caused by the advection from Keihin industrial zone in the southern Kanto region. The present study conducted some investigations, based on station observation datasets, into the characteristics of the spatiotemporal distribution of acidic oxide in the Kanto region. The transport mechanisms of acidic oxide in each season also was investigated through a trajectory analysis. The acidity of precipitation tends to be higher as a whole in summer than in winter in the Kanto region, while the concentration of acid ion increases in winter in a part of the northern Kanto region. The results of the trajectory analysis showed that the source area of sulfur dioxide carried to the Kanto region in winter was likely to be the northern part of China.