Journal of Oceanology and Limnology

, Volume 36, Issue 5, pp 1459–1474 | Cite as

Water masses in the far western equatorial Pacific during the winters of 2010 and 2012

  • Bo Li (李博)
  • Dongliang Yuan (袁东亮)Email author
  • Hui Zhou (周慧)


Conductivity-temperature-depth (CTD) data obtained during the 2010 La Niña winter and the 2012 normal winter, combined with concurrent Argo profiling float data, provide a quasi-synoptic description of the water mass distributions and their variations in the far western equatorial Pacific Ocean. The water mass connection between the western Pacific and the east Indonesian seas is emphasized. Analysis indicates that the North Pacific Tropical Water (NPTW, S >34.9) carried by the Mindanao Current southward and the South Pacific Tropical Water (SPTW, S >35.1) from the southern hemisphere meet in the area. Observations suggest that the southward transport of the NPTW is stronger in 2010 than in 2012 due to enhanced advection of the Mindanao Current. The distribution of SPTW, which crosses the equator in the northwest direction and retroflects back to the interior Pacific Ocean, is found to retreat from 4°–5°N in 2012 to 2°–3°N in 2010 La Niña peak in the 130°E section. A relatively fresh tropical subsurface water is identified in between the NPTW and the SPTW, moving eastward with the North Equatorial Countercurrent into the equatorial Pacific Ocean. However, the salinity maximum of this subsurface fresh water is found to decrease eastward, suggesting that the salinity maximum is generated either by strong diapycnal mixing or by isopycnal mixing of temporally entrained Indonesian sea water into the area.


far western equatorial Pacific North Pacific Tropic Water South Pacific Tropical Water tropical subsurface water La Niña 


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.



Thanks are extended to the crews and scientists of R/V Kexue - 1. Data acquisition and sample collections were supported by the NSFC Open Research Cruise (Cruise Nos. NORC2010-09 and NORC2012-09), funded by the Shiptime Sharing Project of NSFC. This cruise was conducted onboard R/V Kexue-1 by the Institute of Oceanology, Chinese Academy of Sciences.


  1. Akima H. 1970. A new method of interpolation and smooth curve fitting based on local procedures. Journal of the ACM, 17(4): 589–602.CrossRefGoogle Scholar
  2. Bingham F M, Lukas R. 1994. The southward intrusion of North Pacific Intermediate Water along the Mindanao coast. J. Phys. Oceanogr., 24(1): 141–154.CrossRefGoogle Scholar
  3. Bingham F M, Lukas R. 1995. The distribution of intermediate water in the western equatorial pacific during January–February 1986. Deep Sea Research Part I: Oceanographic Research Papers, 42(9): 1 545–1 573.CrossRefGoogle Scholar
  4. Broecker W S. 1991. The great ocean conveyor. Oceanography, 4(2): 79–89.CrossRefGoogle Scholar
  5. Cannon G A. 1966. Tropical waters in the western Pacific Ocean, August–September 1957. D eep Sea Research and Oceanographic Abstracts, 13(6): 1 139–1 148.CrossRefGoogle Scholar
  6. Choi K Y, Vecchi G A, Wittenberg A T. 2015. Nonlinear zonal wind response to ENSO in the CMIP5 models: roles of the zonal and meridional shift of the ITCZ/SPCZ and the simulated climatological precipitation. J. Climate, 28(21): 8 556–8 573.CrossRefGoogle Scholar
  7. Chung C T Y, Power S B, Arblaster J M, Rashid H A, RoffG L. 2014. Nonlinear precipitation response to El Niño and global warming in the Indo–Pacific. Climate Dyn., 42(7–8): 1 837–1 856.CrossRefGoogle Scholar
  8. Delcroix T, Hénin C. 1991. Seasonal and interannual variations of sea surface salinity in the tropical Pacific Ocean. J. Geophys. Res., 96(C12): 22 135–22 150.CrossRefGoogle Scholar
  9. Delcroix T, McPhaden M J. 2002. Interannual sea surface salinity and temperature changes in the western Pacific warm pool during 1992–2000. J. Geophys. Res., 107(C12): 8 002.CrossRefGoogle Scholar
  10. Delcroix T, Picaut J. 1998. Zonal displacement of the western equatorial Pacific “fresh pool”. J. Geophys. Res., 103(C1): 1 087–1 098.CrossRefGoogle Scholar
  11. Delcroix T. 1998. Observed surface oceanic and atmospheric variability in the tropical Pacific at seasonal and ENSO timescales: a tentative overview. J. Geophys. Res., 103(C9): 18 611–18 633.Google Scholar
  12. Ffield A, Gordon A L. 1992. Vertical mixing in the Indonesian thermocline. J. Phys. Oceanogr., 22: 184–195.CrossRefGoogle Scholar
  13. Fine R A, Lukas R, Bingham F M, Warner M J, Gammon R H. 1994. The western equatorial Pacific: A water mass crossroads. J. Geophs. Res., 99(C12): 25 063–25 080.Google Scholar
  14. Gordon A L, Fine R A. 1996. Pathways of water between the Pacific and Indian oceans in the Indonesian seas. Nature, 379(6561): 146–149.CrossRefGoogle Scholar
  15. Gordon A L. 1986. Interocean exchange of thermocline water. J. Geophys. Res., 91(C4): 5 037–5 046.CrossRefGoogle Scholar
  16. Hasunuma K. 1978. Formation of the intermediate salinity minimum in the northwestern Pacific Ocean. Bull. Ocean Res. Inst. Univ. Tokyo, 9: 1–47.Google Scholar
  17. Hu D X, Cui M C, Qu T D, Li Y X. 1991. A subsurface northward current offMindanao identified by dynamic calculation. In: Takanao K ed. Oceanography of Asian Marginal Seas. Elsevier Oceanography Series, 54. Elsevier, New York. p.359–365.Google Scholar
  18. Johnson E S, Lagerloef G S E, Gunn J T, Bonjean F. 2002. Surface salinity advection in the tropical oceans compared with atmospheric freshwater forcing: A trial balance. J. Geophys. Res., 107(C12): 8 014, 1029/2001JC001122.Google Scholar
  19. Kashino Y, Aoyama M, Kawano T, Hendiarti N, Anantasena Y, Muneyama K, Watanabe H. 1996. The water masses between Mindanao and New Guinea. J. Geophys. Res., 101(C5): 12 391–12 400.CrossRefGoogle Scholar
  20. Kashino Y, España N, Syamsudin F, Richards K J, Jensen T, Dutrieux P, Ishida A. 2009. Observations of the North Equatorial current, Mindanao current, and Kuroshio current system during the 2006/07 El Niño and 2007/08 La Niña. J. O ceanogr., 65(3): 325–333.Google Scholar
  21. Kashino Y, Firing E, Hacker P, Sulaiman A, Lukiyanto. 2001. Currents in the Celebes and Maluku Seas, February 1999. Geophys. Res. Lett., 28(7): 1 263–1 266.CrossRefGoogle Scholar
  22. Kashino Y, Ishida A, Kuroda Y. 2005. Variability of the Mindanao current: mooring observation results. Geophys. Res. Lett., 32: L18611, Scholar
  23. Kashino Y, Ueki I, Sasaki H. 2015. Ocean variability east of Mindanao: mooring observations at 7°N, revisited. J. Geophys. Res., 120(4): 2 540–2 554.CrossRefGoogle Scholar
  24. Kashino Y, Watanabe H, Herunadi B, Aoyama M, Hartoyo D. 1999. Current variability at the Pacific entrance of the Indonesian Throughflow. J. Geophys. Res., 104(C5): 11 021–11 035.CrossRefGoogle Scholar
  25. Kim Y Y, Qu T, Jensen T, Miyama T, Mitsudera H, Kang H W, Ishida A. 2004. Seasonal and interannual variations of the North Equatorial Current bifurcation in a high–resolution OGCM, J. Geophys. Res., 109: C03040.Google Scholar
  26. Li Y L, Wang F. 2012. Spreading and salinity change of North Pacific tropical water in the Philippine Sea. J. O ceanogr., 68(3): 439–452.Google Scholar
  27. Lindstrom E, Lukas R, Fine R, Firing E, Godfrey S, Meyers G, Tsuchiya M. 1987. The western equatorial Pacific Ocean circulation study. Nature, 330(6148): 533–537.CrossRefGoogle Scholar
  28. Lu P, McCreary J P Jr. 1995. Influence of the ITCZ on the flow of thermocline water from the subtropical to the equatorial Pacific Ocean. J. Phys. O ceanogr., 25(12): 3 076–3 088.Google Scholar
  29. Lukas R, Firing E, Hacker P, Richardson P L, Collins C A, Fine R, Gammon R. 1991. Observations of the Mindanao current during the Western Equatorial Pacific Ocean circulation study. J. Geophys. Res., 96(C4): 7 089–7 104.Google Scholar
  30. Lukas R, Lindstrom E. 1991. The mixed layer of the western equatorial Pacific Ocean. J. Geophys. Res., 96(S01): 3 343–3 357.Google Scholar
  31. Lukas R. 1988. Interannual fluctuations of the Mindanao current inferred from sea level. J. Geophys. Res., 93(C6): 6 744–6 748.Google Scholar
  32. Maes C, Ando K, Delcroix T, Kessler W S, McPhaden M J, Roemmich D. 2006. Observed correlation of surface salinity, temperature and barrier layer at the eastern edge of the western Pacific warm pool. Geophys. Res. Lett., 33: L06601, Scholar
  33. Nitani H. 1972. Beginning of the Kuroshio. In: Stommel H, Yoshida K eds. Kuroshio: Physical Aspects of Japan Current. University of Washington Press, Washington. p.129–163.Google Scholar
  34. Qu T D, Lindstrom E J. 2004. Northward intrusion of Antarctic Intermediate Water in the western Pacific. J. Phys. Oceanogr., 34: 2 104–2 118.CrossRefGoogle Scholar
  35. Qu T D, Mitsudera H, Yamagata T. 1998. On the western boundary currents in the Philippine Sea. J. Geophys. Res., 103(C4): 7 537–7 548.Google Scholar
  36. Qu T D, Mitsudera H, Yamagata T. 1999. A climatology of the circulation and water mass distribution near the Philippine Coast. J. Phys. Oceanogr., 29(7): 1 488–1 505.CrossRefGoogle Scholar
  37. Qu T D, Song Y T, Maes C. 2014. Sea surface salinity and barrier layer variability in the equatorial Pacific as seen from Aquarius and Argo. J. Geophys. Res., 119(1): 15–29.CrossRefGoogle Scholar
  38. Qu T D, Yu J Y. 2014. ENSO indices from sea surface salinity observed by Aquarius and Argo. J. O ceanogr., 70(4): 367–375.Google Scholar
  39. Reid J L Jr. 1965. Intermediate waters of the Pacific Ocean. In: Johns Hopkins Oceanographic Studies, No. 2. Johns Hopkins Press, Baltimore, Maryland.Google Scholar
  40. Rochford D J. 1960. The intermediate depth waters of the Tasman and Coral Sea. I. The 27. 20σ t surface. Australian Journal of Marine and Freshwater Research, 11(2): 127–147.CrossRefGoogle Scholar
  41. Talley L D. 1993. Distribution and formation of North Pacific Intermediate Water. J. Phys. Oceanog., 23: 517–537.CrossRefGoogle Scholar
  42. Trenberth K E. 1976. Spatial and temporal variations of the Southern Oscillation. Quart. J. Roy. Meteor. Soc., 102(433): 639–653, Scholar
  43. Tsuchiya M, Lukas R, Fine R A, Firing E, Lindstrom E. 1989. Source waters of the Pacific equatorial undercurrent. Progress in Oceanogr aphy, 23(2): 101–147.CrossRefGoogle Scholar
  44. Tsuchiya M. 1968. Upper waters of the intertropical Pacific Ocean. In: Johns Hopkins Oceanographic Studies. No. 4. The Johns Hopkins Press, Baltimore.Google Scholar
  45. Tsuchiya M. 1991. Flow path of the Antarctic Intermediate Water in the western equatorial South Pacific Ocean. Deep Sea Research Part A. Oceanographic Research Papers, 38(Suppl.): S273–S279.Google Scholar
  46. Ueki I, Ando K. 2013. Detection of Pacific tropical water variability by taut–line moorings in the western equatorial Pacific. J. Oceanogr., 69(4): 429–441.CrossRefGoogle Scholar
  47. Wang B. 1995. Interdecadal changes in El Niño Onset in the last four decades. J. Climate, 8: 267–285.CrossRefGoogle Scholar
  48. Wang F, Hu D X. 1998. Dynamic and thermohaline properties of the Mindanao Undercurrent, Part II: thermohaline structure. Chinese Journal of Oceanology and Limnology, 16(3): 206–213.CrossRefGoogle Scholar
  49. Wang F, Hu D X. 2010. Introduction to international NPOCE program. Chinese Journal of Oceanology and Limnology, 28(4): 953.CrossRefGoogle Scholar
  50. Wang F, Li Y L, Wang J N. 2016. Intraseasonal variability of the surface zonal currents in the western tropical pacific ocean: characteristics and mechanisms. J. Phys. Oceanogr., 46(12): 3 639–3 660.CrossRefGoogle Scholar
  51. Wang F, Li Y L, Zhang Y H, Hu D X. 2013. The subsurface water in the North Pacific tropical gyre. Deep Sea Research Part I: Oceanographic Research Papers, 75: 78–92, Scholar
  52. Wyrtki K. 1961. Physical oceanography of the Southeast Asian Waters. In: NAGA Report vol. 2, Scientific Results of Marine Investigations of the South China Sea and the Gulf of Thailand, Scripps Institution of Oceanography. University of California, San Diego, La Joola, CA. 195p.Google Scholar
  53. Xie L L, Tian J W, Hu D X, Wang F. 2009. A quasi–synoptic interpretation of water mass distribution and circulation in the western North Pacific: I. Water mass distribution. Chinese Journal of Oceanology and Limnology, 27(3): 630–639.CrossRefGoogle Scholar
  54. Zenk W, Siedler G, Ishida A, Holfort J, Kashino Y, Kuroda Y, Miyama T, Müller T J. 2005. Pathways and variability of the Antarctic Intermediate Water in the western equatorial Pacific Ocean. Progress in Oceanography, 67(1–2): 245–281.CrossRefGoogle Scholar
  55. Zhang L L, Hu D X, Hu S J, Wang F, Wang F J, Yuan D L. 2014. Mindanao Current/Undercurrent measured by a subsurface mooring. J. Geophys. Res., 119(6): 3 617–3 628.CrossRefGoogle Scholar
  56. Zhao J, Li Y L, Wang F. 2013. Dynamical responses of the west Pacific North Equatorial Countercurrent(NECC) system to El Niño events. J. Geophys. Res., 118(6): 2 828–2 844, Scholar

Copyright information

© Chinese Society for Oceanology and Limnology, Science Press and Springer-Verlag GmbH Germany, part of Springer Nature 2018

Authors and Affiliations

  • Bo Li (李博)
    • 1
    • 4
    • 5
  • Dongliang Yuan (袁东亮)
    • 1
    • 2
    • 3
    Email author
  • Hui Zhou (周慧)
    • 1
  1. 1.Key Laboratory of Ocean Circulation and Waves, Institute of OceanologyChinese Academy of SciencesQingdaoChina
  2. 2.Function Laboratory for Ocean Dynamics and ClimateQingdao National Laboratory for Marine Science and TechnologyQingdaoChina
  3. 3.Qingdao Collaborative Innovation Center of Marine Science and TechnologyQingdaoChina
  4. 4.State Key Laboratory of Tropical Oceanography, South China Sea Institute of OceanologyChinese Academy of SciencesGuangzhouChina
  5. 5.University of the Chinese Academy of SciencesBeijingChina

Personalised recommendations