• Antonov, J., S. Levitus, T. Boyer, M. Conkright, T. O'Brien, and C. Stephens, 1998: Temperature of the Pacific Ocean. Vol. 2, World Ocean Atlas 1998, NOAA Atlas NESDIS 28, 166 pp.

    • Search Google Scholar
    • Export Citation
  • Boyer, T., S. Levitus, J. Antonov, M. Conkright, T. O'Brien, and C. Stephens, 1998: Salinity of the Pacific Ocean. Vol. 5, World Ocean Atlas 1998, NOAA Atlas NESDIS 31, 166 pp.

    • Search Google Scholar
    • Export Citation
  • Giese, B., S. Urizar, and N. Fučkar, 2002: Southern Hemisphere origins of the 1976 climate shift. Geophys. Res. Lett., 29 (2) 1014, doi: 10.1029/2001GL013268.

    • Search Google Scholar
    • Export Citation
  • Gilson, J., D. Roemmich, and B. Cornuelle, 1998: Relationship of TOPEX/Poseidon altimetric height to steric height and circulation in the North Pacific. J. Geophys. Res., 103 (C12) 2794727965.

    • Search Google Scholar
    • Export Citation
  • Gu, D., and G. Philander, 1997: Interdecadal climate fluctuations that depend on exchanges between the Tropics and extratropics. Science, 275 , 805807.

    • Search Google Scholar
    • Export Citation
  • Hanawa, K., and L. Talley, 2001: Mode waters. Ocean Circulation and Climate—Observing and Modelling the Global Ocean, G. Siedler et al., Eds., Academic Press, 373–386.

    • Search Google Scholar
    • Export Citation
  • Harrison, D., and N. Larkin, 1998: El Nino–Southern Oscillation sea surface temperature and wind anomalies, 1946–1993. Rev. Geophys., 36 , 353398.

    • Search Google Scholar
    • Export Citation
  • Hautala, S., and D. Roemmich, 1998: Subtropical mode water in the Northeast Pacific Basin. J. Geophys. Res., 103 (C6) 1305513066.

  • Hosoda, S., S. Xie, K. Takeuchi, and M. Nonaka, 2001: Eastern North Pacific Subtropical Mode Water in a general circulation model: Formation mechanism and salinity effects. J. Geophys. Res., 106 (C9) 1967119681.

    • Search Google Scholar
    • Export Citation
  • Huang, R., and B. Qiu, 1998: The structure of the wind-driven circulation in the subtropical South Pacific Ocean. J. Phys. Oceanogr., 28 , 11731186.

    • Search Google Scholar
    • Export Citation
  • Johnson, G., and D. Moore, 1997: The Pacific subsurface countercurrents and an inertial model. J. Phys. Oceanogr., 27 , 24482459.

  • Johnson, G., and M. McPhaden, 1999: Interior pycnocline flow from the subtropical to the equatorial Pacific Ocean. J. Phys. Oceanogr., 29 , 30733089.

    • Search Google Scholar
    • Export Citation
  • Kleeman, R., J. McCreary Jr., and B. Klinger, 1999: A mechanism for the decadal variation of ENSO. Geophys. Res. Lett., 26 , 17431746.

    • Search Google Scholar
    • Export Citation
  • Ladd, C., and L. Thompson, 2000: Formation mechanisms for North Pacific central and eastern subtropical mode waters. J. Phys. Oceanogr., 30 , 868877.

    • Search Google Scholar
    • Export Citation
  • Ladd, C., and L. Thompson, 2001: Water mass formation in an isopycnal model of the North Pacific. J. Phys. Oceanogr., 31 , 15171537.

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

    • Search Google Scholar
    • Export Citation
  • McCartney, M., 1982: The subtropical recirculation of mode waters. J. Mar. Res., 40 , (Suppl.),. 427464.

  • Oberhuber, J., 1988: An Atlas Based on the COADS Data Set: The Budgets of Heat, Buoyancy and Turbulent Kinetic Energy at the Surface of the Global Ocean. Max-Planck-Institut für Meteorologie, 202 pp.

    • Search Google Scholar
    • Export Citation
  • O'Connor, B., R. Fine, K. Maillet, and D. Olson, 2002: Formation rates of subtropical underwater in the Pacific Ocean. Deep-Sea Res., 49 , 15711590.

    • Search Google Scholar
    • Export Citation
  • Provost, C., C. Escoffier, K. Maamaatuaiahutapu, A. Kartavtseff, and V. Garçon, 1999: Subtropical mode waters in the South Atlantic Ocean. J. Geophys. Res., 104 (C9) 2103321049.

    • Search Google Scholar
    • Export Citation
  • Reid, J., 1973: The shallow salinity minima of the Pacific Ocean. Deep-Sea Res., 20 , 5168.

  • Roemmich, D., and B. Cornuelle, 1992: The subtropical mode waters of the South Pacific Ocean. J. Phys. Oceanogr., 22 , 11781187.

  • Schmitt, R., 1981: Form of the temperature-salinity relationship in the Central Water: Evidence for double-diffusive mixing. J. Phys. Oceanogr., 11 , 10151026.

    • Search Google Scholar
    • Export Citation
  • Siedler, G., A. Kuhl, and W. Zenk, 1987: The Madeira Mode Water. J. Phys. Oceanogr., 17 , 15611570.

  • Stommel, H., 1979: Determination of water mass properties of water pumped down from the Ekman layer to the geostrphic flow below. Proc. Natl. Acad. Sci. USA., 76 , 30513055.

    • Search Google Scholar
    • Export Citation
  • Stramma, L., R. Peterson, and M. Tomczak, 1995: The South Pacific Current. J. Phys. Oceanogr., 25 , 7791.

  • Tomczak, M., and J. Godfrey, 1994: Regional Oceanography: An Introduction. 1st ed. Pergamon Press, 422 pp.

  • Tsuchiya, M., 1981: The origin of the Pacific Equatorial 13°C Water. J. Phys. Oceanogr., 11 , 794812.

  • Tsuchiya, M., and L. Talley, 1996: Water-property distributions along an eastern Pacific hydrographic section at 135°W. J. Mar. Res., 54 , 541564.

    • Search Google Scholar
    • Export Citation
  • Tsuchiya, M., and L. Talley, 1998: A Pacific hydrographic section at 88°W: Water-property distribution. J. Geophys. Res., 103 (C6) 1289912918.

    • Search Google Scholar
    • Export Citation
  • Wijffels, S., J. Toole, and R. Davis, 2001: Revisiting the South Pacific subtropical circulation: A synthesis of World Ocean Circulation Experiment along 32°S. J. Geophys. Res., 106 (C9) 1948119513.

    • Search Google Scholar
    • Export Citation
  • Wong, A., G. Johnson, and W. Owens, 2003: Delayed-mode calibration of autonomous CTD profiling float salinity data by θS climatology. J. Atmos. Oceanic Technol., 20 , 308318.

    • Search Google Scholar
    • Export Citation
  • Zhang, Y., J. Wallace, and D. Battisti, 1997: ENSO-like interdecadal variability: 1900–93. J. Climate, 10 , 10041020.

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South Pacific Eastern Subtropical Mode Water

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  • 1 Joint Institute for Marine and Atmospheric Research, University of Hawaii, and NOAA/Pacific Marine Environmental Laboratory, Seattle, Washington
  • | 2 NOAA/Pacific Marine Environmental Laboratory, Seattle, Washington
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Abstract

The structure, formation, and destruction of South Pacific Eastern Subtropical Mode Water (SPESTMW) are analyzed. Geographic extent and water properties are discussed by using high-quality CTD sections collected between 1991 and 1996. Defined as having a planetary potential vorticity magnitude of less than 3 × 10−10 m−1 s−1, SPESMTW has a volume of about 1.1 × 1015 m3, estimated from CTD data. The ventilation of this mode water is described by using data from a high-resolution XBT section in concert with 30-month time series from profiling CTD floats, some of the first Argo deployments. Published subduction rates allow a mode-water formation rate estimate of 8.7 × 106 m3 s−1. Combining this estimate with the volume yields a residence time of about 4 years. The density-compensating covarying patterns of late winter surface temperature and salinity in the ventilation region of SPESTMW are shown to contribute to the strength of the mode water. However, while the destabilizing salinity gradient in SPESTMW contributes to its formation, it may also hasten its destruction by leaving it susceptible to double-diffusive convective mixing. SPESTMW spreads northwestward from its ventilation region within the subtropical gyre, eventually joining the South Equatorial Current. It is speculated that the proximity of the SPESTMW ventilation region to the Tropics, where winds and sea surface temperatures vary significantly, coupled with a direct interior circulation pathway to the equator, may allow SPESTMW to effect modulation of ENSO dynamics.

Corresponding author address: Annie Wong, PMEL, 7600 Sand Point Way, Bldg. 3, Seattle, WA 98115-6349. Email: annie.wong@noaa.gov

Abstract

The structure, formation, and destruction of South Pacific Eastern Subtropical Mode Water (SPESTMW) are analyzed. Geographic extent and water properties are discussed by using high-quality CTD sections collected between 1991 and 1996. Defined as having a planetary potential vorticity magnitude of less than 3 × 10−10 m−1 s−1, SPESMTW has a volume of about 1.1 × 1015 m3, estimated from CTD data. The ventilation of this mode water is described by using data from a high-resolution XBT section in concert with 30-month time series from profiling CTD floats, some of the first Argo deployments. Published subduction rates allow a mode-water formation rate estimate of 8.7 × 106 m3 s−1. Combining this estimate with the volume yields a residence time of about 4 years. The density-compensating covarying patterns of late winter surface temperature and salinity in the ventilation region of SPESTMW are shown to contribute to the strength of the mode water. However, while the destabilizing salinity gradient in SPESTMW contributes to its formation, it may also hasten its destruction by leaving it susceptible to double-diffusive convective mixing. SPESTMW spreads northwestward from its ventilation region within the subtropical gyre, eventually joining the South Equatorial Current. It is speculated that the proximity of the SPESTMW ventilation region to the Tropics, where winds and sea surface temperatures vary significantly, coupled with a direct interior circulation pathway to the equator, may allow SPESTMW to effect modulation of ENSO dynamics.

Corresponding author address: Annie Wong, PMEL, 7600 Sand Point Way, Bldg. 3, Seattle, WA 98115-6349. Email: annie.wong@noaa.gov

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