• Adcroft, A., J-M. Campin, P. Heimbach, C. Hill, and J. Marshall, cited. 2002: Mitgcm release 1. [Available online at http://mitgcm.org/sealion/.].

  • Antonov, J. I., S. Levitus, and T. P. Boyer, 2002: Steric sea level variations during 1957–1994: Importance of salinity. J. Geophys. Res., 107 .8013, doi:10.1029/2001JC000964.

    • Search Google Scholar
    • Export Citation
  • Arakawa, A., and V. R. Lamb, 1977: Computational design of the basic dynamical processes of the UCLA general circulation model. General Circulation Models of the Atmosphere, J. Chang, Ed., Methods of Computational Physics, Vol. 17, Academic Press, 173–265.

  • Baringer, M. O., and J. C. Larsen, 2001: Sixteen years of Florida current transport at 27°N. Geophys. Res. Lett., 28 , 31793182.

  • Beckmann, A., and R. Döscher, 1997: A method for improved representation of dense water spreading over topography in geopotential-coordinate models. J. Phys. Oceanogr., 27 , 581591.

    • Search Google Scholar
    • Export Citation
  • Bennett, A. F., 2002: Inverse Modeling of the Ocean and Atmosphere. Cambridge University Press, 352 pp.

  • Bryden, H., H. R. Longworth, and S. A. Cunningham, 2005: Slowing of the Atlantic meridional overturning circulation at 25°N. Nature, 438 , 655657.

    • Search Google Scholar
    • Export Citation
  • Cazenave, A., and R. S. Nerem, 2004: Present-day sea level change: Observations and causes. Rev. Geophys., 42 .RG3001, doi:10.1029/2003RG000139.

    • Search Google Scholar
    • Export Citation
  • Cooper, M., and K. Haines, 1996: Altimetric assimilation with water property conservation. J. Geophys. Res., 101 , 10591077.

  • Curry, R. G., and M. S. McCartney, 2001: Ocean gyre circulation changes associated with the North Atlantic Oscillation. J. Phys. Oceanogr., 31 , 33743400.

    • Search Google Scholar
    • Export Citation
  • Daley, R., 1991: Atmospheric Data Analysis. Cambridge University Press, 457 pp.

  • Dickey, J. O., S. L. Marcus, O. de Viron, and I. Fukumori, 2002: Recent earth oblateness variations: Unraveling climate and postglacial rebound effects. Science, 298 , 19751977.

    • Search Google Scholar
    • Export Citation
  • Eden, C., and J. Willebrand, 2001: Mechanism of interannual to decadal variability of the North Atlantic circulation. J. Climate, 14 , 22662280.

    • Search Google Scholar
    • Export Citation
  • Ganachaud, A., and C. Wunsch, 2000: Improved estimates of global ocean circulation, heat transport and mixing from hydrographic data. Nature, 408 , 453457.

    • Search Google Scholar
    • Export Citation
  • Ganachaud, A., and C. Wunsch, 2003: Large-scale ocean heat and freshwater transports during the World Ocean Circulation Experiment. J. Climate, 16 , 696705.

    • Search Google Scholar
    • Export Citation
  • Gent, P. R., and J. C. McWilliams, 1990: Isopycnal mixing in ocean models. J. Phys. Oceanogr., 20 , 150155.

  • Giering, R., and T. Kaminski, 1998: Recipes for adjoint code construction. Assoc. Comput. Mach. Trans. Math. Software, 24 , 437474.

  • Gilbert, J. C., and C. Lemaréchal, 1989: Some numerical experiments with variable-storage quasi-Newton algorithms. Math. Programm., 45 , 407435.

    • Search Google Scholar
    • Export Citation
  • Häkkinen, S., and P. B. Rhines, 2004: Decline of subpolar North Atlantic circulation during the 1990s. Science, 304 , 555559.

  • Kalnay, E., and Coauthors, 1996: The NCEP/NCAR 40-Year Reanalysis Project. Bull. Amer. Meteor. Soc., 77 , 437471.

  • Käse, R. H., and W. Krauss, 1996: The Gulf Stream, the North Atlantic Current, and the origin of the Azores Current. The Warmwatersphere of the North Atlantic Ocean, W. Krauss, Ed., Gebrüder Borntraeger, 291–337.

  • Köhl, A., Y. Lu, P. Heimbach, B. Cornuelle, D. Stammer, and C. Wunsch, and the ECCO Consortium, 2002: The ECCO 1° global WOCE synthesis. ECCO Rep. 20, 33 pp. [Available online at http://www.ecco-group.org/reports.html].

  • Large, W. G., J. C. McWilliams, and S. C. Doney, 1994: Oceanic vertical mixing: A review and a model with nonlocal boundary layer parameterization. Rev. Geophys., 32 , 363403.

    • Search Google Scholar
    • Export Citation
  • Levitus, S., R. Burgett, and T. Boyer, 1994a: Salinity. Vol. 3, World Ocean Atlas 1994, NOAA Atlas NESDIS 3, 99 pp.

  • Levitus, S., R. Burgett, and T. Boyer, 1994b: Temperature. Vol. 4, World Ocean Atlas 1994, NOAA Atlas NESDIS 4, 117 pp.

  • Levitus, S., J. I. Antonov, J. L. Wang, T. L. Delworth, K. W. Dixon, and A. J. Broccoli, 2001: Anthropogenic warming of Earth’s climate system. Science, 292 , 267270.

    • Search Google Scholar
    • Export Citation
  • Levitus, S., J. J. Antonov, and T. Boyer, 2005: Warming of the World Ocean, 1955–2003. Geophys. Res. Lett., 32 .L02604, doi:10.1029/2004GL021592.

    • Search Google Scholar
    • Export Citation
  • Lu, Y., K. Ueyoshi, A. Köhl, E. Remy, K. Lorbacher, and D. Stammer, 2002: Input data sets for the ECCO Global 1° WOCE synthesis. ECCO Rep. 18, 37 pp.

  • Macdonald, A. M., and C. Wunsch, 1996: An estimate of global ocean circulation and heat fluxes. Nature, 382 , 436439.

  • Maltrud, M. E., R. D. Smith, A. J. Semtner, and R. C. Malone, 1998: Global eddy-resolving ocean simulations driven by 1985–1995 atmospheric winds. J. Geophys. Res., 103 , 3082530853.

    • Search Google Scholar
    • Export Citation
  • Marotzke, J., 1992: The role of integration time in determining a steady-state through data assimilation. J. Phys. Oceanogr., 22 , 15561567.

    • Search Google Scholar
    • Export Citation
  • Marotzke, J., and C. Wunsch, 1993: Finding the steady-state of a general-circulation model through data assimilation–Application to the North Atlantic Ocean. J. Geophys. Res., 98 , 2014920167.

    • Search Google Scholar
    • Export Citation
  • Marotzke, J., R. Giering, Q. K. Zhang, D. Stammer, C. N. Hill, and T. Lee, 1999: Construction of the adjoint MIT ocean general circulation model and application to Atlantic heat transport sensitivity. J. Geophys. Res., 104 , 2952929548.

    • Search Google Scholar
    • Export Citation
  • Marshall, J., C. Hill, L. Perelman, and A. Adcroft, 1997a: Hydrostatic, quasi-hydrostatic, and nonhydrostatic ocean modeling. J. Geophys. Res., 102C , 57335752.

    • Search Google Scholar
    • Export Citation
  • Marshall, J., A. Adcroft, C. Hill, L. Perelman, and C. Heisey, 1997b: A finite-volume, incompressible Navier–Stokes model for studies of the ocean on parallel computers. J. Geophys. Res., 102C , 57535766.

    • Search Google Scholar
    • Export Citation
  • Menemenlis, D., and Coauthors, 2005: NASA supercomputer improves prospects for ocean climate research. Eos, Trans. Amer. Meteor. Soc., 86 , 9596.

    • Search Google Scholar
    • Export Citation
  • Miller, L., and B. C. Douglas, 2004: The rate of twentieth-century global sea level rise and its causes are the subjects of intense controversy. Most direct estimates from tide gauges give. Nature, 428 , 406409.

    • Search Google Scholar
    • Export Citation
  • Munk, W., 2003: Ocean freshening, sea level rising. Science, 300 , 20412043.

  • Niiler, P., 2001: The World Ocean surface circulation. Ocean Circulation and Climate, G. Siedler, J. Church, and J. Gould, Eds., International Geophysics Series, Vol. 77, Academic Press, 193–204.

    • Search Google Scholar
    • Export Citation
  • Reynolds, R. W., and T. M. Smith, 1994: Improved global sea surface temperature analysis using optimum interpolation. J. Climate, 7 , 929948.

    • 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.

    • Search Google Scholar
    • Export Citation
  • Schmitz, W. J., and W. S. Richardson, 1968: On the transport of the Florida Current. Deep-Sea Res., 15 , 679693.

  • Smith, W. H. F., and D. T. Sandwell, 1997: Global seafloor topography from satellite altimetry and ship depth soundings. Science, 277 , 195196.

    • Search Google Scholar
    • Export Citation
  • Stammer, D., 1998: On eddy characteristics, eddy transports, and mean flow properties. J. Phys. Oceanogr., 28 , 727739.

  • Stammer, D., C. Wunsch, and R. M. Ponte, 2000: De-aliasing of global high frequency barotropic motions in altimeter observations. Geophys. Res. Lett., 27 , 11751178.

    • Search Google Scholar
    • Export Citation
  • Stammer, D., C. Wunsch, I. Fukumori, and J. Marshall, 2002a: State estimation improves prospects for ocean research. Eos, Trans. Amer. Geophys. Union, 83 .289, 294, 295.

    • Search Google Scholar
    • Export Citation
  • Stammer, D., and Coauthors, 2002b: The global ocean circulation during 1992–1997, estimated from ocean observations and a general circulation model. J. Geophys. Res., 107 .3118, doi:10.1029/2001JC000888.

    • Search Google Scholar
    • Export Citation
  • Stammer, D., F. Wentz, and C. Gentemann, 2003: Validation of new microwave SST measurement for climate purposes. J. Climate, 16 , 7387.

    • Search Google Scholar
    • Export Citation
  • Stammer, D., K. Ueyoshi, A. Köhl, W. B. Large, S. Josey, and C. Wunsch, 2004: Estimating air–sea fluxes of heat, freshwater, and momentum through global ocean data assimilation. J. Geophys. Res., 109 .C05023, doi:10.1029/2003JC002082.

    • Search Google Scholar
    • Export Citation
  • Stammer, D., A. Köhl, and C. Wunsch, 2007: Impact of accurate geoid fields on estimates of the ocean circulation. J. Atmos. Oceanic Technol., in press.

    • Search Google Scholar
    • Export Citation
  • Tapley, B. D., D. P. Chambers, S. Bettadpur, and J. C. Ries, 2003: Large scale ocean circulation from the GRACE GGM01 geoid. Geophys. Res. Lett., 30 .2163, doi:10.1029/2003GL018622.

    • Search Google Scholar
    • Export Citation
  • White, N. J., J. A. Church, and J. M. Gregory, 2005: Coastal and global averaged sea level rise for 1950 to 2000. Geophys. Res. Let., 32 .L01601, doi:10.1029/2004GL021391.

    • Search Google Scholar
    • Export Citation
  • Wijffels, S. E., R. W. Schmitt, H. L. Bryden, and A. Stigebrandt, 1992: Transport of freshwater by the oceans. J. Phys. Oceanogr., 22 , 155162.

    • Search Google Scholar
    • Export Citation
  • Willebrand, J., and Coauthors, 2001: Circulation characteristics in three eddy-permitting models of the North Atlantic. Progress in Oceanography, 48 , Pergamon,. 123161.

    • Search Google Scholar
    • Export Citation
  • Wunsch, C., 1996: The Ocean Circulation Inverse Problem. Cambridge University Press, 442 pp.

  • Wunsch, C., and P. Heimbach, 2006: Estimated decadal changes in the North Atlantic meridional overturning circulation and heat flux 1993–2004. J. Phys. Oceanogr., 36 , 20122024.

    • Search Google Scholar
    • Export Citation
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Interannual to Decadal Changes in the ECCO Global Synthesis

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  • 1 Institut für Meereskunde, Zentrum für Meeres- und Klimaforschung, Universität Hamburg, Hamburg, Germany
  • | 2 Physical Oceanography Research Division, Center for Observations, Modeling, and Predictions, Scripps Institution of Oceanography, University of California, San Diego, La Jolla, California
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Abstract

An estimate of the time-varying global ocean circulation for the period 1992–2002 was obtained by combining most of the World Ocean Circulation Experiment (WOCE) ocean datasets with a general circulation model on a 1° horizontal grid. The estimate exactly satisfies the model equations without artificial sources or sinks of momentum, heat, and freshwater. To bring the model into agreement with observations, its initial temperature and salinity conditions were permitted to change, as were the time-dependent surface fluxes of momentum, heat, and freshwater. The estimation of these “control variables” is largely consistent with accepted uncertainties in the hydrographic climatology and meteorological analyses. The estimated time-mean horizontal transports of volume, heat, and freshwater, which were largely underestimated in the previous 2° optimization performed by Stammer et al., have converged with time-independent estimates from box inversions over most parts of the World Ocean. Trends in the model’s heat content are 7% larger than those reported by Levitus and correspond to a global net heat uptake of about 1.1 W m−2 over the model domain. The associated model trend in sea surface height over the estimation period resembles the observations from Ocean Topography Experiment (TOPEX)/Poseidon over most of the global ocean. Sea surface height changes in the model are primarily steric but show contributions from mass redistributions from the subpolar North Atlantic Ocean and the Southern Ocean to the subtropical Pacific Ocean gyres. Steric contributions are primarily temperature based but are partly compensated by salt variation. However, the North Atlantic and the Southern Ocean reveal a clear contribution of salt to large-scale sea level variations.

Corresponding author address: Detlef Stammer, Institut für Meereskunde, Zentrum für Meeres- und Klimaforschung, Universität Hamburg, D-20146 Hamburg, Germany. Email: stammer@ifm.uni-hamburg.de

This article included in the In Honor of Carl Wunsch special collection.

Abstract

An estimate of the time-varying global ocean circulation for the period 1992–2002 was obtained by combining most of the World Ocean Circulation Experiment (WOCE) ocean datasets with a general circulation model on a 1° horizontal grid. The estimate exactly satisfies the model equations without artificial sources or sinks of momentum, heat, and freshwater. To bring the model into agreement with observations, its initial temperature and salinity conditions were permitted to change, as were the time-dependent surface fluxes of momentum, heat, and freshwater. The estimation of these “control variables” is largely consistent with accepted uncertainties in the hydrographic climatology and meteorological analyses. The estimated time-mean horizontal transports of volume, heat, and freshwater, which were largely underestimated in the previous 2° optimization performed by Stammer et al., have converged with time-independent estimates from box inversions over most parts of the World Ocean. Trends in the model’s heat content are 7% larger than those reported by Levitus and correspond to a global net heat uptake of about 1.1 W m−2 over the model domain. The associated model trend in sea surface height over the estimation period resembles the observations from Ocean Topography Experiment (TOPEX)/Poseidon over most of the global ocean. Sea surface height changes in the model are primarily steric but show contributions from mass redistributions from the subpolar North Atlantic Ocean and the Southern Ocean to the subtropical Pacific Ocean gyres. Steric contributions are primarily temperature based but are partly compensated by salt variation. However, the North Atlantic and the Southern Ocean reveal a clear contribution of salt to large-scale sea level variations.

Corresponding author address: Detlef Stammer, Institut für Meereskunde, Zentrum für Meeres- und Klimaforschung, Universität Hamburg, D-20146 Hamburg, Germany. Email: stammer@ifm.uni-hamburg.de

This article included in the In Honor of Carl Wunsch special collection.

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