Skip to main content
SpringerLink
Log in

Influence of the Oyashio Current and Tsugaru Warm Current on the circulation and water properties of Otsuchi Bay, Japan

  • Special Section: Original Article
  • Oceanographic observations after the 2011 earthquake off the Pacific coast of Tohoku
  • Published:
  • volume 73, pages 115–131 (2017)
Journal of Oceanography Aims and scope Submit manuscript

Cite this article

Abstract

Mooring and hydrographic observations were conducted from September 2012 to May 2014 at the mouth of Otsuchi Bay, a ria along the Pacific coast of Japan. Our observations quantitatively demonstrated that the circulation and the water properties of Otsuchi Bay are strongly influenced by the Tsugaru Warm Current (TWC) and Oyashio Current (OY) at seasonal and subseasonal time scales. Two bottom-mounted velocity profilers and temperature and salinity measurements beneath the near-surface halocline showed a counterclockwise lateral circulation pattern related to the TWC, which was enhanced from summer to autumn. From winter to early spring, the lateral circulation patterns related to the TWC weakened and the influence of the OY occasionally increased. When the OY was weak, surface flows became an overturning structure, with outflows in the upper layer and inflows in the lower layer. When the OY was strong and passed close to the Sanriku coast, the circulation became highly variable and intermittent. Intrusions of the markedly low-salinity OY water were observed on two occasions and persisted for periods of several weeks to several months. Salinity was sometimes less than 33.7, the lower limit of the typical TWC from late summer to autumn even when the TWC dominates. We suggested that this is the seasonal fluctuations of the TWC itself, as the upstream current of the Tsushima Warm Current is freshened in summer as a result of the influence of the Changjiang River. The surface water was generally fresher in the south of the bay than in the north, suggesting the Coriolis deflection of the river plume.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Log in via an institution

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Institutional subscriptions

Fig. 1
Fig. 2
Fig. 3
Fig. 4
Fig. 5
Fig. 6
Fig. 7
Fig. 8
Fig. 9
Fig. 10
Fig. 11
Fig. 12
Fig. 13
Fig. 14

Similar content being viewed by others

References

  • Anbo A, Otobe H, Takagi M (2005) On the river water discharged in Otsuchi Bay. Rep Int Coast Mar Res Cent 30:4–8 (in Japanese)

    Google Scholar 

  • Fukuda A, Katayama A, Yagi Y, Takasu H, Nishibe Y, Tsuda A, Nagata T (2016) Nutrient status of Otsuchi Bay (northeastern Japan) following the 2011 off the Pacific coast of Tohoku Earthquake. J Oceaongr. doi:10.1007/s10872-015-0296-2

    Google Scholar 

  • Gill EA (1982) Atmosphere-ocean dynamics. Academic, San Diego

    Google Scholar 

  • Hanawa M, Mitsudera F (1987) Variation of water system distribution in the Sanriku coastal area. J Oceanogr Soc Japan 42:435–446

    Article  Google Scholar 

  • Itoh S, Kaneko H, Ishizu M, Yanagimoto D, Okunishi T, Nishigaki H, Tanaka K (2016) Fine-scale structure and mixing across the front between the Tsugaru Warm and Oyashio Currents in summer along the Sanriku Coast, east of Japan. J Oceanogr. doi:10.1007/s10872-015-0320-6

    Google Scholar 

  • Kubokawa A (1986) Instability caused by the coalescence of two modes of a one-layer coastal current with a surface front. J Oceanogr Soc Jpn 42:373–380

    Article  Google Scholar 

  • Kusaka A, Azumaya T, Kawasaki Y (2013) Monthly variations of hydrographic structures and water mass distribution off the Doto area, Japan. J Oceaongr 69(3):295–312

    Article  Google Scholar 

  • Masunaga E, Fringer O, Yamazaki H (2016) An observational and numerical study of river plume dynamics in Otsuchi Bay, Japan. J Oceanogr. doi:10.1007/s10872-015-0324-2

    Google Scholar 

  • Nishida Y, Kanomata I, Tanaka I, Sato S, Takahashi S, Matsubara H (2003) Seasonal and interannual variations of the volume transport through the Tsugaru Strait. Oceanogr Jpn 12(5):487–499 (in Japanese)

    Article  Google Scholar 

  • Oguma S, Suzuki T, Nagata Y (2002) Seasonal variations in the sea off Sanriku coast, Japan. J Oceanogr 58:825–835

    Article  Google Scholar 

  • Okazaki M (1990) The circulation of Sea water and variation of the properties in some bays of Sanriku Coast, eastern coast of Northern Japan. Bull Coast Oceanogr 32:15–28 (in Japanese)

    Google Scholar 

  • Okuda K, Mutoh S (1986) Features of the abnormally cold water phenomena in the Tohoku sea area and its cause. Bull Jpn Soc Fish Oceanogr 46:231–238 (in Japanese)

    Google Scholar 

  • Otobe H, Onishi H, Inada M, Michida Y, Terazaki M (2009) Estimation of water circulation in Otsuchi bay, Japan inferred from ADCP observation. Coast Mar Sci 33(1):78–86

    Google Scholar 

  • Sakamoto TT, Urakawa SL, Hasumi H, Itoh S, Ishizu M, Tanaka K (2016) Numerical simulation of Pacific water intrusion into Otsuchi Bay, northeast of Japan, using a nested-grid OGCM. J Oceanogr. doi:10.1007/s10872-015-0344-y

  • Senju T, Ookei N (2012) Hydrographic conditions northwest off the Noto Peninsula in the Japan Sea and its importance to the monitoring of the Tsushima Current. Umi to Sora 87:1–16 (in Japanese with English abstract)

    Google Scholar 

  • Senju T, Enomoto H, Matsuno T, Matsui S (2006) Interannual salinity variations in the Tsushima Strait and its relation to the Changjiang discharge. J Oceanogr 62:681–692

    Article  Google Scholar 

  • Shikama N (1980) Current measurements in Otsuchi Bay. Bul Coast Oceanogr 18:1–8 (in Japanese)

    Google Scholar 

  • Shikama N (1986) Exchange mechanism of water in a ria-type bay along Sanriku coast. Bull Jpn Soc Fish Oceanogr 50:170–174 (in Japanese)

    Google Scholar 

  • Shikama N (1990)Characteristics in flow field of water Otushi Bay. Mar Rese Cent Rep 16:75 (in Japanese)

    Google Scholar 

  • Tanaka KK, Komatsu S, Itoh D, Yanagimoto M, Ishizu H, Hasumi TT, Sakamoto S, Urakawa Y Michida (2016) Baroclinic circulation and its high frequency variability in Otsuchi Bay on the Sanriku ria coast, Japan. J Oceanogr. doi:10.1007/s10872-015-0338-9

    Google Scholar 

  • Tatebe H, Yasuda I (2005) Numerical experiments on the seasonal variations of the Oyashio near the east coast of Japan. J Phys Oceanogr 35:2309–2325

    Article  Google Scholar 

  • Urakawa LS, Kurogi M, Yoshimura K, Hasumi H (2015) Modeling low salinity waters along the coast around Japan using a high resolution river discharge data set. J Oceanogr 71:715–739

    Article  Google Scholar 

  • Valle-Levinson A (2010) Contemporary issues in estuarine physics. Cambridge University, New York, p 1–315

  • Wagawa T, Kuroda H, Ito S-I, Kakehi S, Yamanome T, Tanaka K, Endoh Y, Kaga S (2015) Variability in water properties and predictability of sea surface temperature along Sanriku coast, Japan. Cont Shelf Res 103:12–22. doi:10.1016/j.csr.2015.04.016

    Article  Google Scholar 

Download references

Acknowledgments

This research is a contribution to the Tohoku Ecosystem-Associated Marine Science (TEAMS) project, and Regeneration, Conservation and Sustainable Uses of Living Marine Resource Productivity of the Coastal Ecosystem Complex (CEC) program funded by the Ministry of Education, Culture, Sports, Science and Technology in Japan. We also thank the members of the Fisheries Cooperative for Otsuchi Bay and the captain and crews of the R/V Yayoi. The bathymetric data were provided by the Japan Oceanographic Data Center. The offshore CTD observation data were provided by the Iwate Fisheries Technology Center. The data from the ADCP profilers are available at the Research Information and Data Access Site of TEAMS (RIAS; http://www.i-teams.jp/catalog/rias/e/index.html).

Author information

Authors and Affiliations

  1. International Coastal Research Center, Atmosphere and Ocean Research Institute, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba, 277-8564, Japan

    Miho Ishizu & Kiyoshi Tanaka

  2. Center for Earth Surface System Dynamics, Atmosphere and Ocean Research Institute, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba, 277-8564, Japan

    Sachihiko Itoh

  3. Graduate School of Frontier Sciences, Atmosphere and Ocean Research Institute, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba, 277-8564, Japan

    Kosei Komatsu

Authors
  1. Miho Ishizu
    View author publications

    You can also search for this author in PubMed Google Scholar

  2. Sachihiko Itoh
    View author publications

    You can also search for this author in PubMed Google Scholar

  3. Kiyoshi Tanaka
    View author publications

    You can also search for this author in PubMed Google Scholar

  4. Kosei Komatsu
    View author publications

    You can also search for this author in PubMed Google Scholar

Corresponding author

Correspondence to Miho Ishizu.

Rights and permissions

Reprints and Permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

Ishizu, M., Itoh, S., Tanaka, K. et al. Influence of the Oyashio Current and Tsugaru Warm Current on the circulation and water properties of Otsuchi Bay, Japan. J Oceanogr 73, 115–131 (2017). https://doi.org/10.1007/s10872-016-0383-z

Download citation

  • Received:

  • Revised:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1007/s10872-016-0383-z

Keywords

search

Navigation