• Anderson, D., , and R. Corry, 1985: Ocean response to low frequency wind forcing with application to the seasonal variation in the Florida Straits—Gulf Stream transport. Prog. Oceanogr., 14, 740, doi:10.1016/0079-6611(85)90003-5.

    • Search Google Scholar
    • Export Citation
  • Bindoff, N., , and T. McDougall, 1994: Diagnosing climate change and ocean ventilation using hydrographic data. J. Phys. Oceanogr., 24, 11371152, doi:10.1175/1520-0485(1994)024<1137:DCCAOV>2.0.CO;2.

    • Search Google Scholar
    • Export Citation
  • Cai, W., , T. Cowan, , S. Godfrey, , and S. Wijffels, 2010: Simulations of processes associated with the fast warming rate of the southern midlatitude ocean. J. Climate, 23, 197206, doi:10.1175/2009JCLI3081.1.

    • Search Google Scholar
    • Export Citation
  • Chen, X., , and K.-K. Tung, 2014: Varying planetary heat sink led to global-warming slowdown and acceleration. Science, 345, 897903, doi:10.1126/science.1254937.

    • Search Google Scholar
    • Export Citation
  • Dee, D. P., and et al. , 2011: The ERA-Interim reanalysis: Configuration and performance of the data assimilation system. Quart. J. Roy. Meteor. Soc., 137, 553597, doi:10.1002/qj.828.

    • 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, doi:10.1029/2000JC900063.

    • Search Google Scholar
    • Export Citation
  • Durack, P. J., , and S. E. Wijffels, 2010: Fifty-year trends in global ocean salinities and their relationship to broad-scale warming. J. Climate, 23, 43424362, doi:10.1175/2010JCLI3377.1.

    • Search Google Scholar
    • Export Citation
  • Durack, P. J., , S. E. Wijffels, , and R. J. Matear, 2012: Ocean salinities reveal strong global water cycle intensification during 1950 to 2000. Science, 336, 455458, doi:10.1126/science.1212222.

    • Search Google Scholar
    • Export Citation
  • Gray, A. R., , and S. C. Riser, 2014: A global analysis of Sverdrup balance using absolute geostrophic velocities from Argo. J. Phys. Oceanogr., 44, 12131229, doi:10.1175/JPO-D-12-0206.1.

    • Search Google Scholar
    • Export Citation
  • Hill, K. L., , S. R. Rintoul, , R. Coleman, , and K. R. Ridgway, 2008: Wind forced low frequency variability of the East Australia Current. Geophys. Res. Lett., 35, L08602, doi:10.1029/2007GL032912.

    • Search Google Scholar
    • Export Citation
  • Hill, K. L., , S. R. Rintoul, , K. R. Ridgway, , and P. R. Oke, 2011: Decadal changes in the South Pacific western boundary current system revealed in observations and ocean state estimates. J. Geophys. Res., 116, C01009, doi:10.1029/2009JC005926.

    • Search Google Scholar
    • Export Citation
  • Hosoda, S., , T. Suga, , N. Shikama, , and K. Mizuno, 2009: Global surface layer salinity change detected by Argo and its implication for hydrological cycle intensification. J. Oceanogr., 65, 579586, doi:10.1007/s10872-009-0049-1.

    • Search Google Scholar
    • Export Citation
  • Longhurst, A., , S. Sathyendranath, , T. Platt, , and C. Caverhill, 1995: An estimate of global primary production in the ocean from satellite radiometer data. J. Plankton Res., 17, 12451271, doi:10.1093/plankt/17.6.1245.

    • Search Google Scholar
    • Export Citation
  • Ollitrault, M., , and A. Colin de Verdière, 2014: The ocean general circulation near 1000-m depth. J. Phys. Oceanogr., 44, 384409, doi:10.1175/JPO-D-13-030.1.

    • Search Google Scholar
    • Export Citation
  • Park, J. J., , K. Kim, , B. A. King, , and S. C. Riser, 2005: An advanced method to estimate deep currents from profiling floats. J. Atmos. Oceanic Technol., 22, 12941304, doi:10.1175/JTECH1748.1.

    • Search Google Scholar
    • Export Citation
  • Qiu, B., , and S. Chen, 2006: Decadal variability in the large-scale sea surface height field of the South Pacific Ocean: Observations and causes. J. Phys. Oceanogr., 36, 17511762, doi:10.1175/JPO2943.1.

    • Search Google Scholar
    • Export Citation
  • Reid, J., 1986: On the total geostrophic circulation of the South Pacific Ocean: Flow patterns, tracers, and transports. Prog. Oceanogr., 16, 161, doi:10.1016/0079-6611(86)90036-4.

    • Search Google Scholar
    • Export Citation
  • Reynolds, R. W., , N. A. Rayner, , T. M. Smith, , D. C. Stokes, , and W. Wang, 2002: An improved in situ and satellite SST analysis for climate. J. Climate, 15, 16091625, doi:10.1175/1520-0442(2002)015<1609:AIISAS>2.0.CO;2.

    • Search Google Scholar
    • Export Citation
  • Rhein, M., and et al. , 2013: Observations: Ocean. Climate Change 2013: The Physical Science Basis, T. F. Stocker et al., Eds., Cambridge University Press, 255–315.

  • Ridgway, K. R., , R. C. Coleman, , R. J. Bailey, , and P. Sutton, 2008: Decadal variability of East Australian Current transport inferred from repeated high-density XBT transects, a CTD survey and satellite altimetry. J. Geophys. Res., 113, C08039, doi:10.1029/2007JC004664.

    • Search Google Scholar
    • Export Citation
  • Riser, S., and et al. , 2016: Fifteen years of ocean observations with the global Argo array. Nat. Climate Change, 6, 145153, doi:10.1038/nclimate2872.

    • Search Google Scholar
    • Export Citation
  • Roemmich, D., , and J. Gilson, 2009: The 2004-2008 mean and annual cycle of temperature, salinity, and steric height in the global ocean from the Argo program. Prog. Oceanogr., 82, 81100, doi:10.1016/j.pocean.2009.03.004.

    • Search Google Scholar
    • Export Citation
  • Roemmich, D., , J. Gilson, , R. Davis, , P. Sutton, , S. Wijffels, , and S. Riser, 2007: Decadal spinup of the South Pacific subtropical gyre. J. Phys. Oceanogr., 37, 162173, doi:10.1175/JPO3004.1.

    • Search Google Scholar
    • Export Citation
  • Roemmich, D., , J. Church, , J. Gilson, , D. Monselesan, , P. Sutton, , and S. Wijffels, 2015: Unabated planetary warming and its ocean structure since 2006. Nat. Climate Change, 5, 240245, doi:10.1038/nclimate2513.

    • Search Google Scholar
    • Export Citation
  • Sasaki, Y., , S. Minobe, , N. Schneider, , T. Kagimoto, , M. Nonaka, , and H. Sasaki, 2008: Decadal sea level variability in the South Pacific in a global eddy-resolving ocean model hindcast. J. Phys. Oceanogr., 38, 17311747, doi:10.1175/2007JPO3915.1.

    • Search Google Scholar
    • Export Citation
  • Sutton, P., , and D. Roemmich, 2011: Decadal steric and sea surface height changes in the Southern Hemisphere. Geophys. Res. Lett., 38, L08604, doi:10.1029/2011GL046802.

    • Search Google Scholar
    • Export Citation
  • Swart, N. C., , and J. C. Fyfe, 2012: Observed and simulated changes in the Southern Hemisphere surface westerly wind-stress. Geophys. Res. Lett., 39, L16711, doi:10.1029/2012GL052810.

    • Search Google Scholar
    • Export Citation
  • Trenberth, K., 1997: The definition of El Niño. Bull. Amer. Meteor. Soc., 78, 27712777, doi:10.1175/1520-0477(1997)078<2771:TDOENO>2.0.CO;2.

    • Search Google Scholar
    • Export Citation
  • Wijffels, S., , J. Willis, , C. M. Domingues, , P. Barker, , N. J. White, , A. Gronell, , K. Ridgway, , and J. A. Church, 2008: Changing expendable bathythermograph fall rates and their impact on estimates of thermosteric sea level rise. J. Climate, 21, 56575672, doi:10.1175/2008JCLI2290.1.

    • Search Google Scholar
    • Export Citation
  • Wijffels, S., , D. Roemmich, , D. Monselesan, , J. Church, , and J. Gilson, 2016: Ocean temperatures chronicle the ongoing warming of Earth. Nat. Climate Change, 6, 116118, doi:10.1038/nclimate2924.

    • Search Google Scholar
    • Export Citation
  • Yu, L., , and R. Weller, 2007: Objectively analyzed air–sea heat fluxes for the global ice-free oceans (1981–2005). Bull. Amer. Meteor. Soc., 88, 527539, doi:10.1175/BAMS-88-4-527.

    • Search Google Scholar
    • Export Citation
  • Zilberman, N. V., , D. H. Roemmich, , and S. T. Gille, 2014: Meridional volume transport in the South Pacific: Mean and SAM-related variability. J. Geophys. Res. Oceans, 119, 26582678, doi:10.1002/2013JC009688.

    • Search Google Scholar
    • Export Citation
All Time Past Year Past 30 Days
Abstract Views 0 0 0
Full Text Views 316 316 43
PDF Downloads 271 271 38

Multidecadal Change of the South Pacific Gyre Circulation

View More View Less
  • 1 Scripps Institution of Oceanography, University of California San Diego, La Jolla, California
  • | 2 National Institute of Water and Atmospheric Research, Wellington, New Zealand
  • | 3 Scripps Institution of Oceanography, University of California San Diego, La Jolla, California
© Get Permissions Rent on DeepDyve
Restricted access

Abstract

Multidecadal trends in ocean heat and freshwater content are well documented, but much less evidence exists of long-term changes in ocean circulation. Previously, a 12-yr increase, 1993 to 2004, in the circulation of the South Pacific Subtropical Gyre interior was described. That analysis was based on differences between early Argo and 1990s hydrographic data and changes in sea surface height. Here, it is shown that the trend of increasing circulation continues through 2014, with some differences within the Argo decade (2005 to 2014). Patterns that indicate or are consistent with increasing equatorward transport in the eastern portion of the South Pacific Gyre are seen in Argo temperature and steric height, Argo trajectory velocity, altimetric sea surface height, sea surface temperature, sea level pressure, and wind stress. Between 2005 and 2014 the geostrophic circulation across 35°S, from 160°W to South America, was enhanced by 5 Sv (1 Sv ≡ 106 m3 s−1) of added northward flow. This was countered by a southward transport anomaly between the date line and 160°W. Corresponding temperature trends span the full 2000-m depth range of Argo observations. The 22-yr trend, 1993 to 2014, in sea surface height at 35°S, 160°W is 8 cm decade−1. Trends in sea surface temperature over 34 yr, 1981 to 2014, show a similar spatial pattern to that of sea surface height, with an increase of 0.5°C decade−1 at 35°S, 160°W. These multidecadal trends support the interpretation of the 40°S maximum in global ocean heat gain as resulting from anomalous wind forcing and Ekman convergence.

Denotes Open Access content.

Corresponding author address: Dean Roemmich, Scripps Institution of Oceanography, University of California San Diego, 9500 Gilman Drive, La Jolla CA 92093-0230. E-mail: droemmich@ucsd.edu

Abstract

Multidecadal trends in ocean heat and freshwater content are well documented, but much less evidence exists of long-term changes in ocean circulation. Previously, a 12-yr increase, 1993 to 2004, in the circulation of the South Pacific Subtropical Gyre interior was described. That analysis was based on differences between early Argo and 1990s hydrographic data and changes in sea surface height. Here, it is shown that the trend of increasing circulation continues through 2014, with some differences within the Argo decade (2005 to 2014). Patterns that indicate or are consistent with increasing equatorward transport in the eastern portion of the South Pacific Gyre are seen in Argo temperature and steric height, Argo trajectory velocity, altimetric sea surface height, sea surface temperature, sea level pressure, and wind stress. Between 2005 and 2014 the geostrophic circulation across 35°S, from 160°W to South America, was enhanced by 5 Sv (1 Sv ≡ 106 m3 s−1) of added northward flow. This was countered by a southward transport anomaly between the date line and 160°W. Corresponding temperature trends span the full 2000-m depth range of Argo observations. The 22-yr trend, 1993 to 2014, in sea surface height at 35°S, 160°W is 8 cm decade−1. Trends in sea surface temperature over 34 yr, 1981 to 2014, show a similar spatial pattern to that of sea surface height, with an increase of 0.5°C decade−1 at 35°S, 160°W. These multidecadal trends support the interpretation of the 40°S maximum in global ocean heat gain as resulting from anomalous wind forcing and Ekman convergence.

Denotes Open Access content.

Corresponding author address: Dean Roemmich, Scripps Institution of Oceanography, University of California San Diego, 9500 Gilman Drive, La Jolla CA 92093-0230. E-mail: droemmich@ucsd.edu
Save