Journal of Oceanography

, Volume 58, Issue 6, pp 815–823 | Cite as

Winter Mixed Layer and Formation of Dichothermal Water in the Bering Sea

  • Takahiro Miura
  • Toshio Suga
  • Kimio Hanawa


The temperature minimum layer, called “dichothermal water”, is a characteristic feature of the North Pacific subarctic gyre. In particular, dichothermal water having a density of approximately 26.6 sigma-theta (σθ), which corresponds to the densest water outcropping in winter in the North Pacific, is seen in the Bering Sea. In order to clarify the water properties, and the area in which and the process by which the dichothermal water is formed, a new seasonal mean gridded climatological dataset with a fine resolution for the Bering Sea and adjacent seas has been prepared using historically accumulated hydrographic data. Although the waters of the Alaskan Stream have temperature minimum layers, their temperature inversions are very weak in climatologies and the core densities of the temperature minimum layers are much lighter than 26.6σθ. On the other hand, in the Bering Sea one can see the robust structure of temperature minimum layers, the core density of the dichothermal water being around 26.6σθ. In addition, it has been found that the properties of the dichothermal water observed in the warming season are almost the same as those in the winter mixed layer. That is, the dichothermal waters are formed in the winter mixed layer in the Bering Sea. Since these waters are found in the Kamchatka Strait, i.e., the main exit of the Bering Sea waters, it can be supposed that the dichothermal waters are exported from the Bering Sea to the Pacific Ocean by the Kamchatka Current.

Bering Sea dichothermal layer mixed layer subarctic gyre halocline 


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  1. Dodimead, A. J., F. Favorite and T. Hirano (1963): Salmon of the North Pacific Ocean, Part II. Bull. Int. North Pacific Fish. Comm., 13, 1–195.Google Scholar
  2. Favorite, F., A. J. Dodimead and K. Nasu (1976): Oceanography of the Subarctic Pacific region, 1960 -1971. Bull. Int. North Pacific Fish. Comm., 33, 1–187.Google Scholar
  3. Levitus, S. (1982): Climatological Atlas of the World Ocean. NOAA Professional Paper No. 13. National Oceanic and Atmospheric Administration, Rockville, MD, 173 pp.Google Scholar
  4. Miura, T., T. Suga and K. Hanawa (2002): Numerical study on formation of the dichothermal water in the Bering Sea. J. Oceanogr. (submitted).Google Scholar
  5. NODC (1994): World Ocean Atlas 1994. NODC Internal Report No. 13. National Oceanographic Data Center Ocean Climate Laboratory, Sliver Spring, MD, 30 pp.Google Scholar
  6. NODC (1998): World Ocean Database 1998. NODC Internal Report No. 14. National Oceanographic Data Center Ocean Climate Laboratory, Sliver Spring, MD, 70 pp.Google Scholar
  7. NODC (1999): World Ocean Atlas 1998. NODC Internal Report No. 15. National Oceanographic Data Center Ocean Climate Laboratory, Sliver Spring, MD, 16 pp.Google Scholar
  8. Oberhuber, J. M. (1988): An atlas based on the COADS data set: the budgets of heat, buoyancy and turbulent kinetic energy at the surface of the global ocean. Rep. 15, Max-Planck Inst., Hamburg, Germany, 20 pp.Google Scholar
  9. Ohtani, K. (1973): Oceanographic structure in the Bering Sea. Mem. Fac. Fish., Hokkaido Univ., 21, 65–106.Google Scholar
  10. Ohtani, K., Y. Akiba and A. Y. Takenouti (1972): Formation of western subarctic water in the Bering Sea. p. 31–44. In Biological Oceanography of the Northern North Pacific Ocean, ed. by A. Y. Takenouti, Idemitsu Shoten, Tokyo.Google Scholar
  11. Reed, R. K. (1995): On geostrophic reference levels in the Bering Sea basin. J. Oceanogr., 51, 489–498.CrossRefGoogle Scholar
  12. Roden, G. I. (1995): Aleutian Basin of the Bering Sea: Thermohaline, oxygen, nutrient, and current structure in July 1993. J. Geophys. Res., 100, 13539–13554.CrossRefGoogle Scholar
  13. Stabeno, P. J. and R. K. Reed (1994): Circulation in the Bering Sea basin observed by satellite-tracked drifters: 1986-1993. J. Phys. Oceanogr., 24, 848–854.CrossRefGoogle Scholar
  14. Tomczak, M. and J. S. Godfrey (1994): Regional Oceanography: An Introduction. Pergamon, 422 pp.Google Scholar

Copyright information

© The Oceanographic Society of Japan 2002

Authors and Affiliations

  • Takahiro Miura
    • 1
  • Toshio Suga
    • 1
  • Kimio Hanawa
    • 1
  1. 1.Department of Geophysics, Graduate School of ScienceTohoku UniversityAoba-ku, SendaiJapan

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