Advertisement

Journal of Oceanography

, Volume 69, Issue 2, pp 159–174 | Cite as

Pathway and variability of deep circulation around 40°N in the northwest Pacific Ocean

  • Kojiro Ando
  • Masaki Kawabe
  • Daigo Yanagimoto
  • Shinzou Fujio
Original Article

Abstract

To clarify the global deep-water circulation in the northwest Pacific, we conducted current observations with seven moorings at 40°N east of Japan from May 2007 to October 2008, together with hydrographic observations. By analyzing the data, while taking into consideration that the deep circulation has a northward component in this region and carries low-silica, high-dissolved-oxygen water, we clarified that the deep circulation flows within the region between 144°30′ and 146°10′E at 40°N on and east of the eastern slope of the Japan Trench with marked variability; the deep circulation flows partly on the eastern slope of the trench and mainly to the east during P1 (10 May–24 November 2007), is confined to the eastern slope of the trench during P2 (25 November 2007–20 May 2008), and flows on and to the immediate east of the eastern slope of the trench during P3 (21 May–15 October 2008). Previous studies have identified two branches of the deep circulation at lower latitudes in the western North Pacific; one flows off the western trenches and the other detours near the Shatsky Rise. It was thus concluded that the eastern branch flows westward at 38°N and then northward to the east of the trench, finally joining the western branch around 40°N during P1 and P3, whereas the eastern branch passes westward south of 38°N, joins the western branch around 38°N, and flows northward on the eastern slope of the trench during P2.

Keywords

Deep-water circulation Moored current meters Lower circumpolar deep water Silica Dissolved oxygen Japan Trench Northwest Pacific Basin 

Notes

Acknowledgments

The authors are grateful to Captain S. Suzuki, the crew of the R/V “Hakuho Maru”, and scientists and technical staff who participated in cruises KH-07-1 leg 2 and KH-08-3 leg 2 for their great work and cooperation in the observations. They also thank Ms. Eriko Fukumura for drawing the figures. Comments from two anonymous reviewers were fruitful. This work was supported by KAKENHI (18340136, 23244094) and the Sasakawa Scientific Research Grant from The Japan Science Society.

References

  1. Akima H (1970) A new method of interpolation and smooth curve fitting based on local procedures. J Assoc Comput Mach 17:589–602CrossRefGoogle Scholar
  2. Endoh T, Hibiya T (2007) Meridional overturning circulation of the deep Pacific estimated assuming the vertical advective–diffusive balance. Geophys Res Lett 34(11):L11602CrossRefGoogle Scholar
  3. Fujio S, Yanagimoto D (2005) Deep current measurements at 38°N east of Japan. J Geophys Res 110:C02010. doi: 10.1029/2004JC002288 CrossRefGoogle Scholar
  4. Fujio S, Yanagimoto D, Taira K (2000) Deep current structure above the Izu-Ogasawara Trench. J Geophys Res 105:6377–6386CrossRefGoogle Scholar
  5. Hallock ZR, Teague WJ (1996) Evidence for a North Pacific deep western boundary current. J Geophys Res 101:6617–6624CrossRefGoogle Scholar
  6. Hasumi H, Tatebe H, Kawasaki T, Kurogi M, Sakamoto TT (2010) Progress of North Pacific modeling over the past decade. Deep-Sea Res II 57:1188–1200CrossRefGoogle Scholar
  7. Imawaki S, Taira K, Teramoto T (1984) Mesoscale current fluctuations observed in the deep western North Pacific. J Oceanogr Soc Jpn 40:39–45CrossRefGoogle Scholar
  8. Ishizaki H (1994) A simulation of the abyssal circulation in the North Pacific Ocean. PartI: flow field and comparison with observations. J Phys Oceanogr 24:1941–1954CrossRefGoogle Scholar
  9. Johnson GC, Toole JM (1993) Flow of deep and bottom waters in the Pacific at 10°N. Deep Sea Res I 40:371–394CrossRefGoogle Scholar
  10. Kato F, Kawabe M (2009) Volume transport and distribution of deep circulation at 165°W in the North Pacific. Deep Sea Res I 56:2077–2087CrossRefGoogle Scholar
  11. Kawabe M (1993) Deep water properties and circulation in the western North Pacific. In: Teramoto T (ed) Deep ocean circulation, Physical and Chemical Aspects. Elsevier, Amsterdam, pp 17–37CrossRefGoogle Scholar
  12. Kawabe M, Fujio S (2010) Pacific Ocean circulation based on observation. J Oceanogr 66:389–403CrossRefGoogle Scholar
  13. Kawabe M, Taira K (1995) Flow distribution at 165°E in the Pacific Ocean. In: Sakai H, Nozaki Y (eds) Biogeochemical processes and ocean flux in the Western Pacific. Terra Scientificy (TERRAPUB), Tokyo, pp 629–649Google Scholar
  14. Kawabe M, Fujio S, Yanagimoto D (2003) Deep-water circulation at low latitudes in the western North Pacific. Deep Sea Res I 50:631–656CrossRefGoogle Scholar
  15. Kawabe M, Yanagimoto D, Kitagawa S, Kuroda Y (2005) Variations of the deep western boundary current in Wake Island Passage. Deep Sea Res I 52:1121–1137CrossRefGoogle Scholar
  16. Kawabe M, Yanagimoto D, Kitagawa S (2006) Variations of deep western boundary currents in the Melanesian Basin in the western North Pacific. Deep Sea Res I 53:942–959CrossRefGoogle Scholar
  17. Kawabe M, Fujio S, Yanagimoto D, Tanaka K (2009) Water masses and currents of deep circulation southwest of the Shatsky Rise in the western North Pacific. Deep Sea Res I 56:1675–1687CrossRefGoogle Scholar
  18. Kouketsu S, Fukasawa M, Kaneko I, Kawano T, Uchida H, Doi T, Aoyama M, Murakami K (2009) Changes in water properties and transports along 24°N in the North Pacific between 1985 and 2005. J Geophys Res 114:C01008CrossRefGoogle Scholar
  19. Mantyla AW (1975) On the potential temperature in the abyssal Pacific Ocean. J Mar Res 33:341–354Google Scholar
  20. Mantyla AW, Reid JL (1983) Abyssal characteristics of the World Ocean waters. Deep Sea Res 30:805–833CrossRefGoogle Scholar
  21. Mitsuzawa K, Holloway G (1998) Characteristics of deep currents along trenches in the northwest Pacific. J Geophys Res 103:13085–13092CrossRefGoogle Scholar
  22. Owens WB, Warren BA (2001) Deep circulation in the northwest corner of the Pacific Ocean. Deep Sea Res I 48:959–993CrossRefGoogle Scholar
  23. Reed RK (1969) Deep water properties and flow in the central North Pacific. J Mar Res 27:24–31Google Scholar
  24. Reid JL (1997) On the total geostrophic circulation of the Pacific Ocean: flow patterns, tracers, and transports. Prog Oceanogr 39:263–352CrossRefGoogle Scholar
  25. Roussenov V, Williams RG, Follows MJ, Key RM (2004) Role of bottom water transport and diapycnic mixing in determining the radiocarbon distribution in the Pacific. J Geophys Res 109:C06015. doi: 10.1029/2003JC002188 CrossRefGoogle Scholar
  26. Schmitz WJ Jr, Niiler PP, Koblinsky CJ (1987) Two-year moored instrument results along 152°E. J Geophys Res 92:10826–10834CrossRefGoogle Scholar
  27. Talley LD (2003) Shallow, intermediate, and deep overturning components of the global heat budget. J Phys Oceanogr 33:530–560CrossRefGoogle Scholar
  28. Talley LD (2007) Hydrographic atlas of the world ocean circulation experiment (WOCE). Pacific Ocean, vol 2. International WOCE Project Office, SouthamptonGoogle Scholar
  29. Talley LD, Joyce TM, deSzoeke RA (1991) Transpacific sections at 47°N and 152°W: distribution of properties. Deep Sea Res 38(Suppl):S63–S82Google Scholar
  30. Thompson RORY (1983) Low-pass filters to suppress inertial and tidal frequencies. J Phys Oceanogr 13:1077–1083CrossRefGoogle Scholar
  31. Warren BA, Owens WB (1985) Some preliminary results concerning deep northern-boundary currents in the North Pacific. Prog Oceanogr 14:537–551CrossRefGoogle Scholar
  32. Warren BA, Owens WB (1988) Deep currents in the central subarctic Pacific Ocean. J Phys Oceanogr 18:529–551CrossRefGoogle Scholar
  33. Yanagimoto D, Kawabe M (2007) Deep-circulation flow at mid-latitude in the western North Pacific. Deep Sea Res I 54:2067–2081CrossRefGoogle Scholar
  34. Yanagimoto D, Kawabe M, Fujio S (2010) Direct velocity measurements of deep circulation southwest of the Shatsky Rise in the western North Pacific. Deep Sea Res I 57:328–337CrossRefGoogle Scholar

Copyright information

© The Oceanographic Society of Japan and Springer Japan 2013

Authors and Affiliations

  • Kojiro Ando
    • 1
  • Masaki Kawabe
    • 1
  • Daigo Yanagimoto
    • 1
  • Shinzou Fujio
    • 1
  1. 1.Atmosphere and Ocean Research InstituteThe University of TokyoKashiwaJapan

Personalised recommendations