• Andrews, J. C., M. W. Lawrence, and C. S. Nilsson, 1980: Observations of the Tasman Front. J. Phys. Oceanogr.,10, 1854–1869.

  • Bindoff, N. L., and C. Wunsch, 1992: Comparison of synoptic and climatologically mapped sections in the South Pacific Ocean. J. Climate,5, 631–645.

  • ——, R. Coleman, H. van Gysen, and J. O. Wolff, 1997: The role of heat fluxes and winds on seasonal sea-level signals. Global Geodynamics Coupled with Variations of Atmosphere and Ocean, M. Ooe, Ed., Division of Earth Rotation, National Astronomical Observatory, Japan, 45–57.

  • Boland, F. M., 1971: Temperature–salinity anomalies at depths between 200 m and 800 m in the Tasman Sea. Aust. J. Mar. Freshwater. Res.,22, 55–62.

  • ——, and J. A. Church, 1981: The East Australian Current 1978. Deep-Sea Res.,28A, 937–957.

  • Bretherton, F. P., R. E. Davis, and C. B. Fandry, 1976: A technique for objective analysis and design of oceanographic experiments applied to MODE-73. Deep-Sea Res.,23, 559–582.

  • Chelton, D. B., and M. G. Schlax, 1996: Global observations of oceanic Rossby waves. Science,272, 234–238.

  • ——, R. A. deSzoeke, M. G. Schlax, K. El Naggar, and N. Siwertz, 1998: Geographical variability of the first baroclinic Rossby radius of deformation. J. Phys. Oceanogr.,28, 433–460.

  • Chervin, R. M., A. P. Craig, and A. J. Semtner, 1997: Meridional heat transport variability from a global eddy-resolving ocean model. Assessing Climate Change: Results from the Model Evaluation Consortium for Climate Assessment. Gordon and Breach Science Publishers, 143–168.

  • Church, J. A., 1987: East Australian Current adjacent to the Great Barrier Reef. Aust. J. Mar. Freshwater Res.,38, 671–683.

  • ——, and F. M. Boland, 1983: A permanent undercurrent adjacent to the Great Barrier Reef. J. Phys. Oceanogr.,13, 1747–1749.

  • De Mey, P., and A. R. Robinson, 1987: Assimilation of altimeter eddy fields in a limited area quasi-geostrophic model. J. Phys. Oceanogr.,17, 2280–2293.

  • Fukumori, I., and C. Wunsch, 1991: Efficient representation of the North Atlantic hydrographic and chemical distributions. Progress in Oceanography, Vol. 27, Pergamon Press, 111–195.

  • Godfrey, J. S., 1989: A Sverdrup model of the depth-integrated flow for the World Ocean allowing for island circulations. Geophys. Astrophys. Fluid Dyn.,45, 89–112.

  • ——, G. R. Cresswell, T. J. Golding, and A. F. Pearce, 1980: The separation of the East Australian Current. J. Phys. Oceanogr.,10, 430–440.

  • Haines, K., 1991: A direct method for assimilating sea surface height data into ocean models with adjustments to deep circulation. J. Phys. Oceanogr.,21, 843–868.

  • Hamon, B. V., 1965: The East Australian Current. 1960–1964. Deep-Sea Res.,12, 899–921.

  • Hellerman, S., and M. Rosenstein, 1983: Normal monthly wind stress over the World Ocean with error estimates. J. Phys. Oceanogr.,13, 1093–1104.

  • Holbrook, N. J., 1994: Temperature variability in the Southwest Pacific Ocean between 1955 and 1988. Ph.D. thesis, University of Sydney, 229 pp.

  • ——, and N. L. Bindoff, 1997: Interannual and decadal temperature variability in the southwest Pacific Ocean between 1955 and 1988. J. Climate,10, 1035–1049.

  • Kessler, W. S., 1990: Observations of long Rossby waves in the northern tropical Pacific. J. Geophys. Res.,95, 5183–5217.

  • Killworth, P. D., D. B. Chelton, and R. A. de Szoeke, 1997: The speed of observed and theoretical long extratropical planetary waves. J. Phys. Oceanogr.,27, 1946–1966.

  • Lilley, F. E. M., J. H. Filloux, N. L. Bindoff, I. J. Ferguson, and P. J. Mulhearn, 1986: Barotropic flow of a warm-core ring from seafloor electric measurements. J. Geophys. Res.,91, 12 979–13 109.

  • Maier-Reimer, E., U. Mikolajewicz, and K. Hasselmann, 1993: Mean circulation of the Hamburg LSG OGCM and its sensitivity to the thermohaline surface forcing. J. Phys. Oceanogr.,23, 731–757.

  • Meyers, G., 1979: On the annual Rossby wave in the tropical North Pacific Ocean. J. Phys. Oceanogr.,9, 663–674.

  • Minster, J. F., C. Brossier, and P. Rogel, 1995: Variation of the mean sea level from TOPEX/Poseidon data. J. Geophys. Res.,100, 25 153–25 161.

  • Mulhearn, P. J., 1987: The Tasman Front: A study using satellite infrared imagery. J. Phys. Oceanogr.,17, 1148–1155.

  • ——, J. H. Filloux, F. E. M. Lilley, N. L. Bindoff, and I. J. Ferguson, 1986: Abyssal currents during the formation and passage of a warm-core ring in the East Australian Current. Deep-Sea Res.,33, 1563–1576.

  • ——, ——, ——, ——, and ——, 1988: Comparison between surface, barotropic and abyssal flows during the passage of a warm core ring. Aust. J. Mar. Freshwater Res.,39, 697–707.

  • National Oceanographic Data Center, 1991: CD-ROMs NODC-02 and NODC-03: Global ocean temperature and salinity profiles. Informal Report No. 11, National Oceanographic Data Center, Washington, DC, 14 pp. [Available from National Oceanographic Data Center, User Services Branch, NOAA/NESDIS E/OC21, 1825 Connecticut Ave., NW, Washington, DC 20235.].

  • Pearce, A., 1981: Temperature–salinity relationships in the Tasman Sea. Report 135, CSIRO Marine Laboratories, Cronulla, Australia, 41 pp. [Available from CSIRO Division of Marine Research Library, GPO Box 1538, Hobart TAS 7001, Australia.].

  • Philander, S. G. H., 1979: Variability of the tropical oceans. Dyn. Atmos. Oceans,3, 191–208.

  • Rebert, J. P., J. R. Donguy, G. Eldin, and K. Wyrtki, 1985: Relations between sea level, thermocline depth, heat content, and dynamic height in the tropical Pacific Ocean. J. Geophys. Res.,90, 11 719–11 725.

  • Reid, J. L., 1986: On the total geostrophic circulation of the South Pacific Ocean: Flow patterns, tracers and transports. Progress in Oceanography, Vol. 16, Pergamon Press, 1–61.

  • Ridgway, K. R., and J. S. Godfrey, 1994: Mass and heat budgets in the East Australian current: A direct approach. J. Geophys. Res.,99, 3231–3248.

  • Semtner, A. J., and R. M. Chervin, 1988: A simulation of the global ocean circulation with resolved eddies. J. Geophys. Res.,93, 15 502–15 522.

  • ——, and ——, 1992: Ocean general circulation from a global eddy-resolving model. J. Geophys. Res.,97, 5493–5550.

  • Stammer, D., and C. Wunsch, 1994: Preliminary assessment of the accuracy and precision of TOPEX/Poseidon altimeter data with respect to the large scale ocean. J. Geophys. Res.,99, 24 584–24 604.

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

  • White, W. B., 1977: Annual forcing of baroclinic long waves in the tropical North Pacific Ocean. J. Phys. Oceanogr.,7, 50–61.

  • Woodruff, S. D., R. J. Slutz, R. L. Jenne, and P. M. Steurer, 1987: A Comprehensive Ocean–Atmosphere Data Set. Bull. Amer. Meteor. Soc.,68, 1239–1250.

  • Woodworth, P. L., 1991: The permanent service for mean sea level and the global sea level observing system. J. Coastal Res.,7, 699–710.

  • Wyrtki, K., 1962: Geopotential topographies and associated circulation in the western South Pacific Ocean. Aust. J. Mar. Freshwater Res.,13, 89–105.

All Time Past Year Past 30 Days
Abstract Views 0 0 0
Full Text Views 218 74 2
PDF Downloads 23 14 0

Seasonal Temperature Variability in the Upper Southwest Pacific Ocean

View More View Less
  • 1 School of Earth Sciences, Macquarie University, North Ryde, New South Wales, Australia
  • | 2 Antarctic CRC, University of Tasmania, Hobart, Tasmania, Australia
Restricted access

Abstract

Climatological monthly upper-ocean temperature anomalies from the annual mean in the subtropical southwest Pacific Ocean show a characteristic out-of-phase relationship between the mixed layer and the underlying water. The mixed layer temperature anomalies in the subtropical gyre and midlatitudes are consistent in the spatial distribution and phase expected from solar radiation. However, below the mixed layer, the temperature anomalies between 10°S and 30°S are coherent throughout the water column to 450-m depth and are almost 180° out of phase with the mixed layer temperatures. This pattern of temperature anomalies describes vertical movements of the thermocline more closely linked to the seasonal variations in the wind stress curl.

To test this hypothesis, a one-dimensional linear vorticity model was forced using the Hellerman and Rosenstein monthly wind stresses across the entire width of the South Pacific Ocean. This simple wind-driven model has considerable skill in predicting the gyre-scale pattern of change in the phase and amplitude associated with thermocline variations in the subtropical gyre. Experiments, varying the Rossby wave speed, showed that a better representation is achieved with speeds of 2 to 2.5 times that observed from altimeter observations. Overall, the inclusion of long Rossby waves appears to be a very important contribution to the amplitude of the thermocline depth variations in the southwest Pacific. Furthermore, this important Rossby wave contribution is supported by the large-scale anomaly patterns obtained from more sophisticated three-dimensional dynamical ocean models.

Corresponding author address: Dr. Neil Holbrook, School of Earth Sciences, Macquarie University, North Ryde, NSW 2109, Australia.

Email: Neil.Holbrook@mq.edu.au

Abstract

Climatological monthly upper-ocean temperature anomalies from the annual mean in the subtropical southwest Pacific Ocean show a characteristic out-of-phase relationship between the mixed layer and the underlying water. The mixed layer temperature anomalies in the subtropical gyre and midlatitudes are consistent in the spatial distribution and phase expected from solar radiation. However, below the mixed layer, the temperature anomalies between 10°S and 30°S are coherent throughout the water column to 450-m depth and are almost 180° out of phase with the mixed layer temperatures. This pattern of temperature anomalies describes vertical movements of the thermocline more closely linked to the seasonal variations in the wind stress curl.

To test this hypothesis, a one-dimensional linear vorticity model was forced using the Hellerman and Rosenstein monthly wind stresses across the entire width of the South Pacific Ocean. This simple wind-driven model has considerable skill in predicting the gyre-scale pattern of change in the phase and amplitude associated with thermocline variations in the subtropical gyre. Experiments, varying the Rossby wave speed, showed that a better representation is achieved with speeds of 2 to 2.5 times that observed from altimeter observations. Overall, the inclusion of long Rossby waves appears to be a very important contribution to the amplitude of the thermocline depth variations in the southwest Pacific. Furthermore, this important Rossby wave contribution is supported by the large-scale anomaly patterns obtained from more sophisticated three-dimensional dynamical ocean models.

Corresponding author address: Dr. Neil Holbrook, School of Earth Sciences, Macquarie University, North Ryde, NSW 2109, Australia.

Email: Neil.Holbrook@mq.edu.au

Save