210Pb deposition in the far East Asia: controlling factors of its spatial and temporal variations

In order to better understand the behavior of (210)Pb deposition in Far East Asia, comprehensive data of monthly (210)Pb deposition, which includes several time-series and spatial distribution data at 14 stations in Japan and 2 stations in Taiwan, were analyzed. Pb-210 deposition at most of the sites exhibited a typical seasonal change with higher values in winter and lower values in summer; especially, the greatest (210)Pb deposition in the world occurred in winter at sites beside the Japan Sea. The deposition behavior of (210)Pb in Far East Asia differed between winter and summer. The meteorological phenomenon peculiar to winter of the Japan Sea side, i.e., formation of the Japan Sea convergence zone, might cause the high (210)Pb concentration in rainwater, as may heavy snowfall. The (210)Pb concentration in rainwater showed long-term variability, although this differed between winter and summer. This long-term variability may be related to climatological factors such as El Niño.