Analysis of precipitation chemistry at a rural site in Hiroshima Prefecture, Japan

Event basis measurements of precipitation chemistry at Shobara, the rural a rea of the northeastern part in;Hiroshima Prefecture in Japan, during the p eriod 1984-1988, were assessed for determining the sources of major ions, a nd for understanding the relation between ionic concentrations and synoptic meteorological situations. Seasonal patterns of the volume-weighted mean c oncentrations for major ions except H+ could be characterized by winter max ima and summer minima. Principal component analysis was performed on monthl y ionic deposition. Varimax rotated three principal components accounting f or approximately 90% of the total variance in the data set, could be interp reted to be acid, seasalt and soil. From back-trajectories for an event usi ng 850 hPa winds, it was found that the volume-weighted mean concentration of non-sea-salt (nss -) SO42- for the air-mass transported from the norther n part of Asian Continent was highest, and that the majority of high nss-SO 42- concentrations for an event were observed for the continental air-mass under the condition of light precipitation amount. (C) 1999 Elsevier Scienc e Ltd. All rights reserved.