Monthly deposition rates of non-sea salt (nss-)sulfate from the atmosphere were observed at Toyama (1981Toyama ( -1991 and Wajima (1982Wajima ( -1984, both facing the Sea of Japan. The deposition rates at Toyama and Wajima showed similar seasonal variations with a large increase in winter, showing a good correlation to sodium deposition rate which is one of indicators of transport from the Sea of Japan. Thus, the increase in deposition rate in winter is attributed to the long-distance transport of sulfur diox ide from the Asian continent. The deposition rate and nss-S04 / Na ratio in each winter season during 1981-1991, however, did not show an increase with time, though the annual consumption rate of coal in East Asia increased by more than 50% in the 1980s. When the nss-sulfate deposition rate is plotted against the nss-calcium deposition rate, the deposition rates in the summer season shows a correlation of 1:1 in mole. This suggests that most of the nss-sulfate in summer is due to calcium sulfate emitted from flue gas desulfurization plants. On the contrary, in winter, the large increase in nss-sulfate was coupled with a slight increase in nss-calcium, but the ratio of nss-Ca/nss-S04 was lower than unity. This suggests that nss-sulfate in winter can be a mixture with variable ratios of calcium sulfate in Japan to sulfuric acid converted from sulfur dioxide from the Asian continent.

Harbor structures with suction foundations bring sharp cost reductions over conventional gravity harbor structures consisting of foundation mounds and caissons thanks to their superior structural properties and constructibility.This report presents an outline of the suction foundation structure, a description of a corroborative field test, and a summary of the results of the primary analysis of measurement data obtained during suction foundation penetration.

Masashi MIYASAKA Buoyancy-driven vertical piling breakwater-a new type of breakwater formed by upper and lower steel pipes rises above sea level by feeding the air into the upper pipe when high waves or tsunamis are imminent , whereas it normally rests inside the lower pile installed below seabed so that navigation is undisturbed . This paper outlines the results of a series of experiments by a large scale physical model and of the numerical analyses with regard to the rising / sinking behavior of the breakwater. The results clearly demonstrate that: 1) The time required for raising the upper pipe is just a few minutes, being rapid enough to prevent tsunamis from attacking harbors; and 2) The numerical model gives good approximation and is fairly applicable.