駿河灣東北隅淡島大謀網附近の海況に就て(績報 II) : 水温・塩分及び透明度の変化と相互關係
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1. Remarkable changes in water temperature, seemingly keeping pace with the tidal currents, were observed at the hydrographical station near Awasima Isle, in the lower layers of water during the stratification periods1). 7.3°C on July 30, 1933 and 9.1°C on August 25, 1934 were the greatest values, in the respective years, of the difference in temperature at 25m, recorded between two successive observations, which were carried out with several hours intermissions. The water so cool as 14 to 15°C appeared in the lower layers of about 20m in summer, when the air temperature was about 30°C. Such cool water must have been carried there by the tidal currents from the bottom of the wider north-eastern area of Suruga Bay about 100m deep, where a mass of water at the same temperature was found to be spreaded. 2. The quality of the sea-water at the station is determined by the proportion of mixing of (A) the surface water of Kurosio (Japan Current), (B) the water of River Kano and (C) the bottom water spreaded in the wider north-eastern area of the bay. The surface waters are mainly affected by the inflow of the river-water (B) and the water of lower layers by the upwelling of the bottom water (C), while the waters of intermediate layers by all of the three kinds. Consequently, the thermo-haline curve at the station assumes an hyperbolic curve, as shown in Fig. 6. The deformation of such a thermo-haline curve from decade to decade enabled the author to discuss the quantities of the three kinds of waters inflowing to the station. In such a longer variations, temperature or salinity at the surface attains the maximum or the minimum values sooner than in the lower layers. The surface salinity attains generally the minimum values about one and half days earlier than transparency or the salinity at 25m, suggesting the different type of the current at both levels.