Journal of Oceanography

, Volume 74, Issue 4, pp 393–420 | Cite as

Identification of the fronts from the Kuroshio Extension to the Subarctic Current using absolute dynamic topographies in satellite altimetry products

  • Hideyuki Nakano
  • Hiroyuki Tsujino
  • Kei Sakamoto
  • Shogo Urakawa
  • Takahiro Toyoda
  • Goro Yamanaka
Original Article


The climatologies and variabilities of the fronts associated with the Kuroshio Extension (KE), the Kuroshio Extension Northern Branch (KENB), the flow along the Subarctic Boundary (SAB), and the Subarctic Current (SAC) are identified by a new method based on the absolute dynamic height product from the archiving, validation, and interpretation of satellite oceanographic data (the AVISO product). The fronts are detected by examining the specific contour values of the absolute dynamic topography (ADT) in the AVISO product. The (time-varying) specific contour values are decided from the local maxima of the averaged surface geostrophic velocity along the ADT. Assuming the specific contours as the front locations, we obtain an occurrence frequency map of the four front locations, and determine the monthly variability of the fronts over the 1993–2015 period. The results are validated by hydrographic observations. The KE and KENB east of the Shatsky Rise migrate southward several times at a speed of ~ 0.2 cm s−1, while the SAB and SAC are mostly stationary.


Front identification Kuroshio extension Kuroshio bifurcation northern branch Subarctic boundary current Subarctic current AVISO 



We thank the members of the Oceanography and Geochemistry Research Department of MRI for many fruitful discussions and comments. This work is funded by MRI and is partly supported by JSPS KAKENHI Grant Number JP 17K05649. Wavelet analysis was conducted using python programs translated from the Fortran by Dr. Toru Miyama. Discussion with Dr. Katsuro Katsumata with regard to the front identification method in the Southern Ocean quite helpful. Comments from the reviewers and the editor, Dr. Eitarou Oka, greatly improve the manuscript. Except for the wavelet analysis, graphics were produced with the Grid Analysis and Display System (GrADS).


  1. Ambe D, Imawaki S, Uchida H, Ichikawa K (2004) Estimating the Kuroshio axis south of Japan using combination of satellite altimetry and drifting buoys. J Oceanogr 60:375–382CrossRefGoogle Scholar
  2. Aoki K, Kutsuwada K (2008) Verification of the wind-driven transport in the North Pacific subtropical gyre using gridded wind-stress products. J Oceanogr 64:49–60CrossRefGoogle Scholar
  3. AVISO (2016) Ssalto/Ducas user handbook: (M)SLA and (M)ADT near-real time and delayed time products SALP-MU-P-EA-21065-CLS, 5.0 edGoogle Scholar
  4. Belkin I, Krisfield R, Honjo S (2002) Decadal variability of the North Pacific Polar Front: subsurface warming versus surface cooling. Geophys Res Lett 29:1351. CrossRefGoogle Scholar
  5. Belkin I, Cornillon P (2007) Fronts in the world ocean’s large marine ecosystems. ICES CM, pp 21–33Google Scholar
  6. Chao SY (1994) Zonal jets over topography on a beta-plane, with application to the Kuroshio Extension over the Shatsky Rise. J Phys Oceanogr 24:1512–1531CrossRefGoogle Scholar
  7. Chapman C (2014) Southern Ocean jets and how to find them: improving and comparing common jet detection methods. J Geophys Res Oceans 119:4318–4339. CrossRefGoogle Scholar
  8. Chen S (2008) The Kuroshio Extension front from satellite sea surface temperature measurements. J Oceanogr 64:891–897. CrossRefGoogle Scholar
  9. Chen C, Kamenkovich I, Berloff P (2016) Eddy trains and striations in quasigeostrophic simulations and the ocean. J Phys Oceanogr 46:2807–2825CrossRefGoogle Scholar
  10. Chierici M, Fransson A, Nojiri Y (2006) Biogeochemical processes as drivers of surface fCO2 in contrasting provinces in the subarctic North Pacific Ocean. Glob Biogeochem Cycles 20:GB1009. CrossRefGoogle Scholar
  11. Ducet N, Le Traon PY (2001) A comparison of surface eddy kinetic energy and Reynolds stresses in the Gulf Stream and the Kuroshio current systems from merged Topex/Poseidon and Ers-1/2 altimetric data. J Geophys Res 106:16603–16622CrossRefGoogle Scholar
  12. Frankignoul C, Sennechael N, Kwon YO, Alexander MA (2011) Influence of the meridional shifts of the Kuroshio and the Oyashio Extensions on the atmospheric circulation. J Clim 24:762–777CrossRefGoogle Scholar
  13. Favorite F, Dodimead AJ, Nasu K (1976) Oceanography of the subarctic Pacific region, 1960–1971. Bull Int N Pac Fish Comm 33:1–187Google Scholar
  14. Gonźalez-Haro C, Isern-Fontanet J (2014) Global ocean current reconstruction from altimetric and microwave SST measurements. J Geophys Res 119:3378–3391. CrossRefGoogle Scholar
  15. Hellerman S, Rosenstein M (1983) Normal monthly wind stress over the world ocean with error estimates. J Phys Oceanogr 13:1093–1104CrossRefGoogle Scholar
  16. Harada N, Sato M, Seki O, Timmermann A, Moossen H, Bendle J, Nakamura Y, Kimoto K, Okazaki Y, Nagashima K, Gorbarenko SA, Ijiri A, Nakatsuka T, Menviel L, Chikamoto M, Abe-Ouchi A, Schouten S (2011) Sea surface temperature changes during the last glacial maximum and deglaciation. Deep Sea Res II 61–64:93–105. Google Scholar
  17. Hosoda R, Ohira T, Nakamora T (2008) A monthly mean dataset of global oceanic temperature and salinity derived from Argo float observations. JAMSTEC Rep Res Dev 8:47–59CrossRefGoogle Scholar
  18. Howe P, Donohue K, Watts D (2009) Stream-coordinate structure and variability of the Kuroshio Extension. Deep Sea Res I 56:1093–1116CrossRefGoogle Scholar
  19. Hurlburt H, Metzger J (1998) Bifurcation of the Kuroshio Extension at the Shatsky Rise. J Geophys Res 103:7549–7566CrossRefGoogle Scholar
  20. Isoguchi O, Kawamura H, Oka E (2006) Quasi-stationary jets transporting surface warm waters across the transition zone between the subtropical and the subarctic gyres in the North Pacific. J Geophys Res 111:C10003. CrossRefGoogle Scholar
  21. Itoh S, Yasuda I (2010) Characteristics of mesoscale eddies in the Kuroshio–Oyashio Extension region detected from the distribution of the sea surface height anomaly. J Phys Oceanogr 40:1018–1034. CrossRefGoogle Scholar
  22. Iwao T, Endoh M, Shikama N, Nakano T (2003) Intermediate circulation in the northwestern North Pacific derived from subsurface floats. J Oceanogr 59:893–904CrossRefGoogle Scholar
  23. Kara AB, Rochford PA, Hurlburt HE (2000) Mixed layer depth variability and barrier layer formation over the North Pacific Ocean. J Geophys Res 105:16783–16801CrossRefGoogle Scholar
  24. Kawai H (1972) Hydrography of the Kuroshio Extension. In: Stommel H, Yoshida K (eds) Kuroshio: its physical aspects. University of Tokyo Press, Tokyo, pp 235–352Google Scholar
  25. Kida S, Mitsudera H, Aoki S, Guo X, Ito S, Kobashi F, Komori N, Kubokawa A, Miyama T, Morie R, Nakamura H, Nakamura T, Nakano H, Nishigaki H, Nonaka M, Sasaki H, Sasaki YN, Suga T, Sugimoto S, Taguchi B, Takaya K, Tozuka T, Tsujino H, Usui N (2015) Oceanic fronts and jets around Japan: a review. J Oceanogr 71:469–497CrossRefGoogle Scholar
  26. Kouketsu S, Tomita H, Oka E, Hosoda S, Kobayashi T, Sato K (2012) The role of meso-scale eddies in mixed layer deepening and mode water formation in the western North Pacific. J Oceanogr 68:63–77. CrossRefGoogle Scholar
  27. Kwon Y, Alexander MA, Bond NA, Frankignoul C, Nakamura H, Qiu B, Thompson L (2010) Role of the Gulf stream and Kuroshio–Oyashio systems in large-scale atmosphere–ocean interaction: a review. J Clim 23(3249):3281. Google Scholar
  28. Levine ER, White WB (1983) Bathymetric influences upon the character of North Pacific fronts. J Geophys Res 88:9617–9625CrossRefGoogle Scholar
  29. Liu Y, Liang XS, Weisberg RH (2007) Rectification of the bias in the wavelet power spectrum. J Atmos Ocean Tech 24:2093–2102CrossRefGoogle Scholar
  30. Mizuno K, White W (1983) Annual and interannual variability in the Kuroshio current system. J Phys Oceanogr 13:1847–1867CrossRefGoogle Scholar
  31. Nakamura H (1996) A pycnostad on the bottom of the ventilated portion in the central subtropical North Pacific: its distribution and formation. J Oceanogr 52:171–188CrossRefGoogle Scholar
  32. Nakamura H, Lin G, Yamagata T (1997) Decadal climate variability in the North Pacific during recent decades. Bull Am Meteorol Soc 78:2215–2225CrossRefGoogle Scholar
  33. Nakamura H, Kazmin AS (2003) Decadal changes in the North Pacific frontal zones as revealed in ship and satellite observations. J Geophys Res 108:C33078Google Scholar
  34. Nakano H, Tsujino H, Furue R (2008) The Kuroshio current system as a jet and twin relative recirculation gyres embedded in the Sverdrup circulation. Dyn Atmos Ocean 45:135–164. CrossRefGoogle Scholar
  35. Nonaka M, Nakamura H, Tanimoto Y, Kagimoto T, Sasaki H (2006) Decadal variability in the Kuroshio–Oyashio Extension simulated in an eddy-resolving OGCM. J Clim 19:1970–1989CrossRefGoogle Scholar
  36. Niiler P, Maximenko N, Panteleev G, Yamagata T, Olson D (2003) Near-surface dynamical structure of the Kuroshio Extension. J Geophys Res 108:3193. CrossRefGoogle Scholar
  37. Oka E, Qiu B (2012) Progress of North Pacific mode water research in the past decade. J Oceanogr 68:5–20CrossRefGoogle Scholar
  38. Oka E, Uehara K, Nakano T, Suga T, Yanagimoto D, Kouketsu S, Itoh S, Katsura S, Talley LD (2014) Synoptic observation of central mode water in its formation region in spring 2003. J Oceanogr 70:521–534CrossRefGoogle Scholar
  39. Qiu B, Chen S (2005) Variability of the Kuroshio Extension jet, recirculation gyre, and mesoscale eddies on decadal time series. J Phys Oceanogr 35:2090–2103CrossRefGoogle Scholar
  40. Qiu B, Chen S, Hacker P, Hogg NG, Jayne SR, Sasaki H (2008) The Kuroshio Extension northern recirculation gyre: profiling float measurements and forcing mechanism. J Phys Oceanogr 38:1764–1779. CrossRefGoogle Scholar
  41. Qiu B, Chen S, Schneider N (2017) Dynamical links between the decadal variability of the Oyashio and Kuroshio extensions. J Clim 30:9591–9605. CrossRefGoogle Scholar
  42. Qiu B, Chen S, Schneider N, Taguchi B (2014) A coupled decadal prediction of the dynamic state of the Kuroshio Extension system. J Clim 27:1751–1764CrossRefGoogle Scholar
  43. Qu T, Mitsudera H, Qiu B (2001) A climatological view of the Kuroshio Oyashio system east of Japan. J Phys Oceanogr 31:2575–2589CrossRefGoogle Scholar
  44. Rio M-H, Mulet S, Picot N (2013) New global mean dynamic topography from a GOCE geoid model, altimeter measurements and oceanographic in-situ data. In: Proceedings of the ESA living planet symposium, Edinburgh, September 2013Google Scholar
  45. Rio M-H, Mulet S, Picot N (2014) Beyond GOCE for the ocean circulation estimate: synergetic use of altimetry, gravimetry, and in situ data provides new insight into geostrophic and Ekman currents. Geophys Res Lett 41:8918–8925. CrossRefGoogle Scholar
  46. Roden GI (1972) Temperature and salinity fronts at the boundaries of subarctic–subtropical transition zone in the western Pacific. J Geophys Res 77:7175–7187CrossRefGoogle Scholar
  47. Roden GI, Taft BA, Ebbesmeyer CC (1982) Oceanographic aspects of the Emperor Seamounts region. J Geophys Res 87:9537–9552CrossRefGoogle Scholar
  48. Sager W, Zhang J, Korenaga J, Sano T, Koppers A, Widdowson M, Mahoney J (2013) An immense shield volcano within the Shatsky Rise oceanic plateau, northwestern Pacific Ocean. Nat Geosci 6:976–981. CrossRefGoogle Scholar
  49. Sainz-Trapaga S, Goni G, Sugimoto T (2001) Identification of the Kuroshio Extension, its bifurcation and northern branch from altimetry and hydrographic data during October 1992–August 1999: spatial and temporal variability. Geophys Res Lett 28:1759–1762CrossRefGoogle Scholar
  50. Saito H, Suga T, Hanawa K, Watanabe T (2007) New type of pycnostad in the western subtropical-subarctic transition region of the North Pacific: transition region mode water. J Oceanogr 63:589–600CrossRefGoogle Scholar
  51. Sasaki YN, Minobe S (2015) Climatological mean features and interannual to decadal variability of ring formations in the Kuroshio Extension region. J Oceanogr 71:499–509. CrossRefGoogle Scholar
  52. Sasano D, Takatani Y, Kosugi N, Nakano T, Midorikawa T, Ishii M (2015) Multi-decadal trends of oxygen and their controlling factors in the western North Pacific. Glob Biogeochem Cycles 29:935–958. CrossRefGoogle Scholar
  53. Shimizu Y, Iwao T, Yasuda I, Ito SI, Watanabe T, Uehara K, Shikama N, Nakano T (2004) Formation process of North Pacific intermediate water revealed by profiling floats set to drift on 26.7\(\sigma _{\theta }\) isopycnal surface. J Oceanogr 60:453–462CrossRefGoogle Scholar
  54. Sokolov S, Rintoul SR (2007) Multiple jets of the Antarctic circumpolar current south of Australia. J Phys Oceanogr 37:1394–1412CrossRefGoogle Scholar
  55. Stammer D (1997) Steric and wind-induced changes in TOPEX/POSEIDON large-scale sea surface topography observations. J Geophys Res 102:20987–21009CrossRefGoogle Scholar
  56. Suga T, Motoki K, Hanawa K (2003) Subsurface water masses in the central North Pacific transition region: the repeat section along the 180 meridian. J Oceanogr 59:435–444CrossRefGoogle Scholar
  57. Suga T, Motoki K, Aoki Y, Macdonald AM (2004) The North Pacific climatology of winter mixed layer and mode waters. J Phys Oceanogr 34:3–22CrossRefGoogle Scholar
  58. Sugimoto S, Hanawa K (2012) Relationship between the path of the Kuroshio in the south of Japan and the path of the Kuroshio Extension in the east. J Oceanogr 68:129–225. Google Scholar
  59. Talley LD (1993) Distribution and formation of North Pacific intermediate water. J Phys Oceanogr 23:517–537CrossRefGoogle Scholar
  60. Thompson A, Richards K (2011) Low frequency variability of Southern Ocean jets. J Geophys Res 116:C09022. Google Scholar
  61. Torrence C, Compo G (1998) A practical guide to wavelet analysis. Bull Am Meteorol Soc 79:61–78.\(<\)0061:APGTWA\(>\)2.0.CO;2Google Scholar
  62. Uda M (1963) Oceanography of the subarctic Pacific Ocean. J Fish Res Bd Can 20:119–179CrossRefGoogle Scholar
  63. Ueno H, Yasuda I (2000) Distribution and formation of the mesothermal structure (temperature inversions) in the North Pacific subarctic region. J Geophys Res 105:16885–16897CrossRefGoogle Scholar
  64. Yaremchuk MI, Maximenko NA (2002) A dynamically consistent analysis of the mesoscale eddy field at the western North Pacific Subarctic front. J Geophys Res 107:3223. CrossRefGoogle Scholar
  65. Yasuda I (2003) Hydrographic structure and variability in the Kuroshio–Oyashio transition area. J Oceanogr 59:389–402CrossRefGoogle Scholar
  66. Yuan X, Talley LD (1996) The subarctic frontal zone in the North Pacific: characteristics of frontal structure from climatological data and synoptic surveys. J Geophys Res 101:16491–16508CrossRefGoogle Scholar
  67. Wagawa T, Yoshikawa Y, Isoda Y, Oka E, Uehara K, Nakano T, Kuma K, Takagi S (2012) Flow fields around the Emperor Seamounts detected from current data. J Geophys Res 117:C06006. CrossRefGoogle Scholar
  68. Wagawa T, Ito SI, Shimizu Y, Kakehi S, Ambe D (2014) Current associated with the quasi-stationary jet separated from the Kuroshio Extension. J Phys Oceanogr 44:1636–1653. CrossRefGoogle Scholar
  69. Zhang RX, Hanawa K (1993) Features of the water-mass front in the northwestern North Pacific. J Geophys Res 98:967–975CrossRefGoogle Scholar

Copyright information

© The Oceanographic Society of Japan and Springer Japan KK, part of Springer Nature 2018

Authors and Affiliations

  1. 1.Meteorological Research InstituteTsukubaJapan

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