An analysis of precipitation chemistry measurements in Shimane, Japan

Abstract

In order to understand the concentration and deposition levels of the major ions in Shimane, on the Japan Sea coast where precipitation chemistry data are scarce, the precipitation was collected at three sites (Matsue, Gotsu and Masuda) from April 1985 to March 1988. The mean precipitation chemistry was very close to each other except for the seasalt concentration. Masuda showed a halved seasalt contribution compared with the other sites. The volume-weighted annual pH mean at each site ranged from 4.6 to 4.9. Nitrate to SO 4 −2 equivalent ratios were in the range of 0.2 and 0.4 throughout the year. Ammonia and calcium species are interpreted to have neutralized approximately 70% of the original sulfuric and nitric acids. The annual depositions of the major ions in g m −2y −1 were as follows: H +; 0.023–0.037, NH 4 +; 0.57–0.68, Ca 2+; 0.51–0.92, SO 4 2−; 3.29–5.04, NO 3 −; 1.20–1.70. These levels are of the same intensity as corresponding values of JEA network results.