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Journal of Oceanography

, Volume 58, Issue 6, pp 825–835 | Cite as

Seasonal Variations in the Sea off Sanriku Coast, Japan

  • Sachiko Oguma
  • Toru Suzuki
  • Yutaka Nagata
Article

Abstract

The temperature and salinity data obtained by the Iwate Fisheries Technology Center for the 25-year period from 1971 to 1995 were analyzed to clarify the seasonal variations in the sea off Sanriku, Japan. The variations of three typical waters found in this region, the Tsugaru Current water, the Oyashio water, and the Kuroshio water are discussed in terms, of a T-S scatter diagram referring to the water mass classification proposed by Hanawa and Mitsudera (1986). The mean temperature and salinity fields averaged for each month show clear seasonal variation. Distributions of the Tsugaru Current water and the Oyashio water can barely be distinguished in the fields deeper than 200 m since the Tsugaru Current has a shallow structure; however, the fields at 100 m depth indicate remarkable seasonal variation in the area of the Tsugaru Current. At 100 m depth, the temperature and salinity fronts between the Tsugaru Current water and the Oyashio water gradually disappear in January through April, appear again in May, then become clearest in September.

Seasonal variation Tsugaru Current First Branch of the Oyashio Oyashio water Kuroshio water Mixed Water Region the sea off Sanriku 

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References

  1. Amano, K. (1986): Study on Variations of Oceanic Structure in the Sea off Aomori Prefecture—II. Data book published by Aomori Prefectural Fisheries Station, 364 pp. (in Japanese).Google Scholar
  2. Hanawa, K. and H. Mitsudera (1986): Variation of water system distribution in the Sanriku coastal area. J. Oceanogr. Soc. Japan, 42, 435–446.CrossRefGoogle Scholar
  3. Kawai, H. (1972): Hydrography of the Kuroshio Extension. p. 235–352. In Kuroshio, Its Physical Aspect, ed. by H. Stommel and K. Yoshida, Chap. 8, Univ. of Tokyo Press.Google Scholar
  4. MIRC (2001): MIRC Ocean Dataset 2001. MIRC Technical Report No. 1.Google Scholar
  5. Mizuno, K. (1984): Notes 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).Google Scholar
  6. Muto, S., T. Sano, M. Hirai, H. Kudo, K. Yao and Y. Yamamura (1969): The hydrographical study in the coastal sea region off Sanriku. Bull. Tohoku Reg. Fish. Res. Lab., 29, 93–123 (in Japanese with English abstract).Google Scholar
  7. Oguma, S., T. Suzuki, Y. Nagata, H. Watanabe, H. Yamaguchi and S. Takasugi (1999): Errors in oceanic dataset often generated in data processing and in data management—II Case of the Iwate Fisheries Technology Center and treatment of duplicated data. J. Japan Soc. Marine Sur. and Tech., 11, 11–18 (in Japanese with English abstract).Google Scholar
  8. Okuda, K. (1986): Occurrence of extremely low temperature in the coastal region of the Tohoku area associated with interannual variation of the Oyashio. Bull. Tohoku Reg. Fish. Res. Lab. 48, 87–96 (in Japanese with English abstract).Google Scholar
  9. Sekine, Y. (1988): Anomalous intrusion of the Oyashio east of Japan. 1. Influence of the interannual and seasonal variation in the wind stress over the North Pacific. J. Geophy. Res., 93, 2247–2277.CrossRefGoogle Scholar
  10. Takasugi, S. (1992): Distribution of Tsugaru Warm Current Water in the Iwate coastal area and their influence to the sea surface temperature at coastal hydrographic station. Fish. Oceanogr., 56, 434–448 (in Japanese with English abstract).Google Scholar
  11. Talley, D. L., Y. Nagata, T. Iwao, T. Kono, D. Inagake, M. Hirai and K. Okuda (1995): North Pacific Intermediate Water in the Kuroshio/Oyashio Mixed Water Region. J. Phys. Oceanogr., 25, 475–501.CrossRefGoogle Scholar

Copyright information

© The Oceanographic Society of Japan 2002

Authors and Affiliations

  • Sachiko Oguma
    • 1
  • Toru Suzuki
    • 1
  • Yutaka Nagata
    • 1
  1. 1.Marine Information Research CenterJapan Hydrographic AssociationTokyoJapan

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