Abstract
We analyzed hydrographic data obtained monthly by the Iwate Prefectural Fisheries Laboratory during 1977–1981. Our attention was focussed on the classification of waters based on the Temperature-Salinity (T-S) scatter diagram analyses, and on the extraction of the “mean state” of their distribution for each season. The “water system” was defined as “all waters occupying some specific region on the T-S plane”, and the mean state for each season was expressed by the distribution of the “mode water systems” (i.e., the most commonly occuring water system).
Because of the coexistence of the Tsugaru Warm Current, the Oyashio and the Kuroshio, and their large seasonal variability, the sea waters had a wide variety of T-S combinations. The detailed T-S scatter diagram analyses allowed us to classify the waters into six water systems. A time-longitude diagram of water systems and the distribution of mode water systems are presented. The latter showed clear seasonal variations of the Tsugaru Warm Current and the Oyashio.
Though the water system analysis was successfully able to present the distribution of the various waters in the Sanriku Coastal Area and to clearly extract the mean state of sea conditions, it was found that the classification of water systems on the T-S plane was not complete in all cases for this area.
Similar content being viewed by others
References
Akabane, M. and K. Takahashi (1977): Oceanographical structure at the east and west sections of the Tsugaru Strait. Proc. Meeting of Tohoku District Oceanic Community, 40–44. (in Japanese).
Fisheries Agency (1981, 1982, 1983, 1983 and 1984): The Results of Fisheries Oceanographical Observation 1977, 1978, 1979, 1980 and 1981.
Hanawa, K. (1983): Sea surface temperature off Sanriku Coast and east of Tsugaru Strait by Ferry Ishikari (I) 1981. Tohoku Geophys. J.,29, 192–222.
Hanawa, K. (1984): Coastal boundary current. Bull. Coast. Oceanogr.,22, 67–82. (in Japanese).
Ichikawa, H., T. Takahashi and A. Maeda (1983): Oceanic conditions in the continental shelf margine. Bull. Jap. Soc. Fish. Oceanogr.,43, 21–26. (in Japanese).
Ichiye, T. (1956a): On the movement of the upper water in the Polar Front region. Oceanogr. Mag.,8, 29–40.
Ichiye, T. (1956b): On the properties of the isolated cold and fresh water along the edge of the Kuroshio. Oceanogr. Mag.,8, 53–64.
Johbashi, H. and K. Nishiyama (1983): The remarkable northward deviation of the Kuroshio Current axis, east of Honshu in 1979. Umi to Sora,58, 149–156. (in Japanese with English abstract and captions).
Kajiura, K., M. Tsuchiya and K. Hidaka (1958): The analysis of oceanographical condition in the Japan Sea. Rep. Develop. Fisher. Resour. in the Tsushima Warm Current,1. 158–170. (in Japanese).
Kawai, H. (1972a): Hydrography of the Kuroshio extention. p. 235–352. In: Kuroshio, ed. by H. Stommel and K. Yoshida, Univ. Tokyo Press, Tokyo.
Kawai, H. (1972b): Hydrography of the Kuroshio and the Oyashio. p. 129–320. In: Physical Oceanography II, Kaiyokagaku Kiso Koza (Fundamental Lectures of Oceanography), Tokai Univ. Press, Tokyo. (in Japanese).
Masuzawa, J. (1952): On the intermediate water in the northeastern sea of Japan (Second Paper). Oceanogr. Rep. Central Meteorol. Obs.,2, 241–245. (in Japanese with English abstract).
Masuzawa, J. and K. Hasunuma (1977): Water system in the ocean. p. 1–113. In: Physical Oceanography IV, Kaiyokagaku Kiso Koza (Fundamental Lectures of Oceanography), Tokai Univ. Press, Tokyo. (in Japanese).
Mizuno, K. (1984): Note on the hydrographic variability in the vicinity of the east coast of Japan. Bull. Tohoku Reg. Fish. Res. Lab.,46, 61–80. (in Japanese with English abstract and captions).
Mutoh, S. (1985): II. Physics in Sanriku coastal area. p. 220–232. In: Coastal Oceanography of Japanese Islands, Tokai Univ. Press, Tokyo. (in Japanese).
Mutoh, S., K. Sano, M. Hirai, H. Kudoh, K. Yano and Y. Yano (1969): The hydrographic study in the coastal region off Sanriku. 1. The variation of southward flow of Tsugaru Warm Current. Bull. Tohoku Reg. Fish. Res. Lab.,29, 93–123. (in Japanese with English abstract).
Ohtani, K. (1971): Studies on the change of the hydrographic conditions in the Funka Bay. II. Characteristics of the water occupying the Funka Bay. Bull. Fac. Fish. Hokkaido Univ.,22, 58–66. (in Japanese with English abstract).
Okuda, K. (1986): Occurrence of extremely lowtemperature in the coastal region of the Tohoku area associated with interannual variations of the Oyashio. Bull. Tohoku Reg. Fish. Lab.,48, 87–96. (in Japanese with English captions).
Okuda, K. and S. Mutoh (1986): Features of the abnormally cold water phenomena in the Tohoku sea area and its cause. Bull. Jap. Soc. Fish. Oceanogr.,46, 231–238. (in Japanese).
Science and Technology Agency (1979): Report of synthetic studies on the Tsugaru Warm Current region, 335 pp. (in Japanese).
Toba, Y., K. Tomizawa, Y. Kurasawa and K. Hanawa (1982): Seasonal and year-to-year variability of the Tsushima-Tsugaru Warm Current system and its possible cause. La mer,20, 41–51.
Ueno, Y. (1982): On the sea condition at the encrouchment of the Oyashio to the coast of Iwate Prefecture in winter and spring. Ohtsuchi Mar. Cent. Rep.,8, 110–112. (in Japanese).
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Hanawa, K., Mitsudera, H. Variation of water system distribution in the Sanriku Coastal Area. Journal of the Oceanographical Society of Japan 42, 435–446 (1986). https://doi.org/10.1007/BF02110194
Received:
Revised:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/BF02110194