Fig.7. Salinity and density (sigma-t) cross-sections along the line which is produced by connecting the cross-marks in Fig.5. The portion where the salinity is higher than 35.00 is shown by a shaded area. The dates of the observations are shown in the upper column.
4.2 R/V Takuyo in May, 1981
The R/V Takuyo of the Hydrographic Department,Japan Maritime Safety Agency found the abnormally saline water at 5 stations in the region under consideration in May,1981(Table 1). The observation area of the R/V Takuyo extends further toward east,and the abnormally saline water was also found on the observation line along 138゜E. Here we shall analyze the whole data taken by the R/V Takuyo in May 1981.
The observation lines are shown in Fig.5. The observations consist of two legs ：off from Suruga Bay to Enshunada on May 8-12,and off the Kii Peninsula and Shikoku on May 18-22. The portions where the abnormally saline water was found are shown by bold lines,and the cross-marks indicate the places where the highest salinity value was found and/or the thickest stratum of abnormally saline water was found in each north-south section. The current field and path of the Kuroshio (upper figure of Fig.6) and temperature field at 200m level (lower figure of Fig.6) are cited from the Prompt Report of Oceanic State (13-31 May,1981) issued by the Hydrographic Department, MSA. The observed abnormally saline water is located near the southern boundary of the observation area, and north-south extent night be greater than seen in Fig.5.
The salinity and density (sigma-t) cross-sections are shown in Fig.7 along the line which is produced by connecting the cross-marks in Fig.5. The abnormally saline water was found far to the south of the Kuroshio in this case,and might be in the weak current zone of the Kuroshio Counter Current flowing southwestward (see the upper figure of Fig.6). As the abnormally saline water was observed in both of two legs of the voyage by the R/V Takuyo, the time scale of the water mass might be longer than observed in August,1984. Another different characteristic of this saline water is that its domain extends to the surface.
4.3 Observation along the 137゜E meridian
The other abnormally saline water were observed along the 137゜E meridian：by the R/V Shumpu-maru of the Kobe Marine Observatory,JMA on May 4,1981 (a) and October 13, 1981 (b), and the R/V Ryofu-maru of the Japan Meteorological Agency on July 21, 1991 (c). The northsouth cross-sections of the salinity and the density (sigma-t) of these observations are shown in Figs. 8a through 8c,respectively. The abnormally saline water extends to the surface in cases (a) and (c),and is found in the mid-layer in case (b). The Sub-surface saline water higher than 34.90 in Fig.8a (also Fig.5) suggests that the abnormally saline water occasionally extends further in the sub-surface layers.
