• Andres, M., J.-H. Park, M. Wimbush, X.-H. Zhu, H. Nakamura, K. Kim, and K.-I. Chang, 2009: Manifestation of the Pacific decadal oscillation in the Kuroshio. Geophys. Res. Lett., 36, L16602, doi:10.1029/2009GL039216.

    • Search Google Scholar
    • Export Citation
  • Ceballos, L., E. Di Lorenzo, C. D. Hoyos, N. Schneider, and B. Taguchi, 2009: North Pacific Gyre oscillation synchronizes climate variability in the eastern and western boundary current systems. J. Climate, 22, 51635174.

    • Search Google Scholar
    • Export Citation
  • Chang, Y.-L., and L.-Y. Oey, 2012: The Philippines–Taiwan Oscillation: Monsoon-like interannual oscillation of the subtropical–tropical western North Pacific wind system and its impact on the ocean. J. Climate, 25, 15971618.

    • Search Google Scholar
    • Export Citation
  • Chen, S., and B. Qiu, 2010: Mesoscale eddies northeast of the Hawaiian archipelago from satellite altimeter observations. J. Geophys. Res., 115, C03016, doi:10.1029/2009JC005698.

    • Search Google Scholar
    • Export Citation
  • Ducet, N., P.-Y. Le Traon, and G. Reverdin, 2000: Global high-resolution mapping of ocean circulation from TOPEX/Poseidon and ERS-1 and -2. J. Geophys. Res., 105, 19 47719 498.

    • Search Google Scholar
    • Export Citation
  • Flament, P., S. Kennan, R. Lumpkin, M. Sawyer, and E. Stroup, 1998: The ocean. Atlas of Hawaii, S. P. Juvik and J. O. Juvik, Eds., University of Hawaii Press, 82–86.

  • Hosoda, S., T. Ohira, and T. Nakamura, 2008: A monthly mean dataset of global oceanic temperature and salinity derived from Argo float observations. JAMSTEC Rep. Res. Dev., 8, 4759.

    • Search Google Scholar
    • Export Citation
  • Huang, R. X., and B. Qiu, 1994: Three-dimensional structure of the wind-driven circulation in the subtropical North Pacific. J. Phys. Oceanogr., 24, 16081622.

    • Search Google Scholar
    • Export Citation
  • Kazmin, A. S., and M. M. Rienecker, 1996: Variability and frontogenesis in the large-scale oceanic frontal zones. J. Geophys. Res., 101 (C1), 907921.

    • Search Google Scholar
    • Export Citation
  • Kelly, K. A., R. J. Small, R. M. Samelson, B. Qiu, T. M. Joyce, Y.-O. Kwon, and M. F. Cronin, 2010: Western boundary currents and frontal air–sea interaction: Gulf Stream and Kuroshio Extension. J. Climate, 23, 56445667.

    • Search Google Scholar
    • Export Citation
  • Kistler, R., and Coauthors, 2001: The NCEP–NCAR 50-year reanalysis: Monthly means CD-ROM and documentation. Bull. Amer. Meteor. Soc., 82, 247267.

    • Search Google Scholar
    • Export Citation
  • Kobashi, F., and H. Kawamura, 2002: Seasonal variation and instability nature of the North Pacific Subtropical Countercurrent and the Hawaiian Lee Countercurrent. J. Geophys. Res., 107, C03185, doi:10.1029/2001JC001225.

    • Search Google Scholar
    • Export Citation
  • Kobashi, F., and A. Kubokawa, 2012: Review on North Pacific subtropical countercurrents and subtropical fronts: Role of mode waters in ocean circulation and climate. J. Oceanogr., 68, 113126.

    • Search Google Scholar
    • Export Citation
  • Kobashi, F., and S.-P. Xie, 2012: Interannual variability of the North Pacific subtropical countercurrent: Role of local ocean-atmosphere interaction. J. Oceanogr., 68, 2143.

    • Search Google Scholar
    • Export Citation
  • Kobashi, F., H. Mitsudera, and S.-P. Xie, 2006: Three subtropical fronts in the North Pacific: Observational evidence for mode water-induced subsurface frontogenesis. J. Geophys. Res., 111, C09033, doi:10.1029/2006JC003479.

    • Search Google Scholar
    • Export Citation
  • Mantua, N. J., S. R. Hare, Y. Zhang, J. M. Wallace, and R. C. Francis, 1997: A Pacific interdecadal climate oscillation with impacts on salmon production. Bull. Amer. Meteor. Soc., 78, 10691079.

    • Search Google Scholar
    • Export Citation
  • Nakamura, H., and A. S. Kazmin, 2003: Decadal changes in the North Pacific oceanic frontal zones as revealed in ship and satellite observations. J. Geophys. Res., 108, C03078, doi:10.1029/1999JC000085.

    • Search Google Scholar
    • Export Citation
  • Nakano, H., and I. Ishikawa, 2010: Meridional shift of the Kuroshio Extension induced by response of recirculation gyre to decadal wind variations. Deep-Sea Res. II, 57, 11111126.

    • Search Google Scholar
    • Export Citation
  • Nishikawa, S., H. Tsujino, K. Sakamoto, and H. Nakano, 2010: Effects of mesoscale eddies on subduction and distribution of Subtropical Mode Water in an eddy-resolving OGCM of the western North Pacific. J. Phys. Oceanogr., 40, 17481765.

    • Search Google Scholar
    • Export Citation
  • Noh, Y., B. Y. Yim, S. H. You, J. H. Yoon, and B. Qiu, 2007: Seasonal variation of eddy kinetic energy of the North Pacific Subtropical Countercurrent simulated by an eddy-resolving OGCM. Geophys. Res. Lett., 34, L07601, doi:10.1029/2006GL029130.

    • Search Google Scholar
    • Export Citation
  • Nonaka, M., S.-P. Xie, and H. Sasaki, 2012: Interannual variations in low potential vorticity water and the subtropical countercurrent in an eddy-resolving OGCM. J. Oceanogr., 68, 139150.

    • Search Google Scholar
    • Export Citation
  • Oka, E., and B. Qiu, 2012: Progress of North Pacific mode water research in the past decade. J. Oceanogr., 68, 520.

  • Qiu, B., 1999: Seasonal eddy field modulation of the North Pacific Subtropical Countercurrent: TOPEX/Poseidon observations and theory. J. Phys. Oceanogr., 29, 24712486.

    • Search Google Scholar
    • Export Citation
  • Qiu, B., 2002: The Kuroshio Extension system: Its large-scale variability and role in the midlatitude ocean-atmosphere interaction. J. Oceanogr., 58, 5775.

    • Search Google Scholar
    • Export Citation
  • Qiu, B., and S. Chen, 2005: Variability of the Kuroshio Extension jet, recirculation gyre and mesoscale eddies on decadal timescales. J. Phys. Oceanogr., 35, 20902103.

    • Search Google Scholar
    • Export Citation
  • Qiu, B., and S. Chen, 2010: Interannual variability of the North Pacific subtropical countercurrent and its associated mesoscale eddy field. J. Phys. Oceanogr., 40, 213225.

    • Search Google Scholar
    • Export Citation
  • Qiu, B., and S. Chen, 2011: Effect of decadal Kuroshio Extension jet and eddy variability on the modification of North Pacific Intermediate Water. J. Phys. Oceanogr., 41, 503515.

    • Search Google Scholar
    • Export Citation
  • Qiu, B., D. Koh, C. Lumpkin, and P. Flament, 1997: Existence and formation mechanism of the North Hawaiian Ridge Current. J. Phys. Oceanogr., 27, 431444.

    • Search Google Scholar
    • Export Citation
  • Rio, M. H., S. Guinehut, and G. Larnicol, 2011: New CNES-CLS09 global mean dynamic topography computed from the combination of GRACE data, altimetry, and in-situ measurements. J. Geophys. Res., 116, C07018, doi:10.1029/2010JC006505.

    • Search Google Scholar
    • Export Citation
  • Roden, G. I., 1975: On North Pacific temperature, salinity, sound velocity and density fronts and their relation to the wind and energy flux fields. J. Phys. Oceanogr., 5, 557571.

    • Search Google Scholar
    • Export Citation
  • Roemmich, D., and J. Gilson, 2001: Eddy transport of heat and thermocline waters in the North Pacific: A key to interannual/decadal climate variability? J. Phys. Oceanogr., 31, 675687.

    • Search Google Scholar
    • Export Citation
  • Roemmich, D., and Coauthors, 2009: Argo—Observing the global ocean with profiling floats. Oceanography (Wash. D.C.), 22, 3443.

  • Sasaki, H., S.-P. Xie, B. Taguchi, M. Nonaka, S. Hosoda, and Y. Masumoto, 2012: Interannual variations of the Hawaiian Lee Countercurrent induced by potential vorticity variability in the subsurface. J. Oceanogr., 68, 93111.

    • Search Google Scholar
    • Export Citation
  • Sugimoto, S., K. Hanawa, T. Yasuda, and G. Yamanaka, 2012: Low-frequency variations of the eastern Subtropical Front in the North Pacific in an eddy-resolving ocean general circulation model: Roles of central mode water in the formation and maintenance. J. Oceanogr., 68, 521531.

    • Search Google Scholar
    • Export Citation
  • Taguchi, B., S.-P. Xie, N. Schneider, M. Nonaka, H. Sasaki, and Y. Sasai, 2007: Decadal variability of the Kuroshio Extension. Observations and an eddy-resolving model hindcast. J. Climate, 20, 23572377.

    • Search Google Scholar
    • Export Citation
  • Wallace, J. M., and D. S. Gutzler, 1981: Teleconnections in the geopotential height field during the Northern Hemisphere winter. Mon. Wea. Rev., 109, 784812.

    • Search Google Scholar
    • Export Citation
  • Xie, S.-P., W. T. Liu, Q. Liu, and M. Nonaka, 2001: Far-reaching effects of the Hawaiian Islands on the Pacific ocean-atmosphere system. Science, 292, 20572060.

    • Search Google Scholar
    • Export Citation
  • Xie, S.-P., L.-X. Xu, Q. Liu, and F. Kobashi, 2011: Dynamical role of mode-water ventilation in decadal variability in the central subtropical gyre of the North Pacific. J. Climate, 24, 12121225.

    • Search Google Scholar
    • Export Citation
  • Yamanaka, G., H. Ishizaki, M. Hirabara, and I. Ishikawa, 2008: Decadal variability of the Subtropical Front of the western North Pacific in an eddy-resolving ocean general circulation model. J. Geophys. Res., 113, C12027, doi:10.1029/2008JC005002.

    • Search Google Scholar
    • Export Citation
  • Yoshida, S., B. Qiu, and P. Hacker, 2011: Low-frequency eddy modulations in the Hawaiian Lee Countercurrent: Observations and connection to the Pacific Decadal Oscillation. J. Geophys. Res., 116, C12009, doi:10.1029/2011JC007286.

    • Search Google Scholar
    • Export Citation
All Time Past Year Past 30 Days
Abstract Views 0 0 0
Full Text Views 345 181 20
PDF Downloads 296 155 11

Concurrent Decadal Mesoscale Eddy Modulations in the Western North Pacific Subtropical Gyre

Bo QiuDepartment of Oceanography, University of Hawaii at Manoa, Honolulu, Hawaii

Search for other papers by Bo Qiu in
Current site
Google Scholar
PubMed
Close
and
Shuiming ChenDepartment of Oceanography, University of Hawaii at Manoa, Honolulu, Hawaii

Search for other papers by Shuiming Chen in
Current site
Google Scholar
PubMed
Close
Restricted access

Abstract

Satellite altimeter data of the past two decades are used to investigate the low-frequency mesoscale eddy variability inside the western North Pacific subtropical gyre. Eddy activity modulations with a decadal time scale are detected concurrently within the 18°–28°N band, including the three branches of the Subtropical Countercurrent (STCC) and the Hawaiian Lee Countercurrent (HLCC). Lagging behind the Pacific decadal oscillation (PDO) index by six months, enhanced eddy activities were detected in 1995–98 and 2003–06, whereas the eddy activities were below the average in 1999–2002 and 2009–11. Analysis of the temperature and salinity data that became available after 2001 via the International Argo Program reveals that the modulating eddy activities are due to the decadal change in the upper-ocean eastward shear in the broad-scale STCC–HLCC band. By conducting an upper-ocean temperature budget analysis, the authors found that this observed eastward shear change can be effectively accounted for by the decadal-varying surface heat flux forcing. Using the Argo-based temperature and salinity data, it is further found that the decadal subsurface potential vorticity (PV) signals to the north and beneath the STCC–HLCC were vertically coherent and not confined to the mode water isopycnals. Adjusting to the PDO-related surface forcing, these subsurface PV anomalies lagged behind the upper-ocean eastward shear signals and likely made minor contributions to generate the decadal-varying eddy signals observed in the western North Pacific subtropical gyre.

Corresponding author address: Dr. Bo Qiu, Department of Oceanography, University of Hawaii at Manoa, 1000 Pope Road, Honolulu, HI 96822. E-mail: bo@soest.hawaii.edu

Abstract

Satellite altimeter data of the past two decades are used to investigate the low-frequency mesoscale eddy variability inside the western North Pacific subtropical gyre. Eddy activity modulations with a decadal time scale are detected concurrently within the 18°–28°N band, including the three branches of the Subtropical Countercurrent (STCC) and the Hawaiian Lee Countercurrent (HLCC). Lagging behind the Pacific decadal oscillation (PDO) index by six months, enhanced eddy activities were detected in 1995–98 and 2003–06, whereas the eddy activities were below the average in 1999–2002 and 2009–11. Analysis of the temperature and salinity data that became available after 2001 via the International Argo Program reveals that the modulating eddy activities are due to the decadal change in the upper-ocean eastward shear in the broad-scale STCC–HLCC band. By conducting an upper-ocean temperature budget analysis, the authors found that this observed eastward shear change can be effectively accounted for by the decadal-varying surface heat flux forcing. Using the Argo-based temperature and salinity data, it is further found that the decadal subsurface potential vorticity (PV) signals to the north and beneath the STCC–HLCC were vertically coherent and not confined to the mode water isopycnals. Adjusting to the PDO-related surface forcing, these subsurface PV anomalies lagged behind the upper-ocean eastward shear signals and likely made minor contributions to generate the decadal-varying eddy signals observed in the western North Pacific subtropical gyre.

Corresponding author address: Dr. Bo Qiu, Department of Oceanography, University of Hawaii at Manoa, 1000 Pope Road, Honolulu, HI 96822. E-mail: bo@soest.hawaii.edu
Save