Atmospheric equilibrium, instability and energy transport at the last glacial maximum

Abstract

A range of diagnostics from two GCM simulations, one of the present-day climate and one of the last glacial maximum (LGM) is used to gain insight into their different temperature structures and eddy dynamics. There are large local increases in baroclinicity at the LGM, especially in the Atlantic storm track, with large accompanying increases in the low level transient eddy heat flux. However, the differences in the zonal mean are much smaller, and the increases in both baroclinicity and heat flux are confined to low levels. Supplementary experiments with baroclinic wave lifecycles confirm the marked contrast between local and zonal mean behaviour, but do not adequately explain the differences between the zonal mean climates. The total flux of energy across latitude circles in the Northern Hemisphere does not change much during DJF, although its transient component is actually reduced at the LGM (during JJA the transient component is increased). Calculations of total linear eddy diffusivity reveal that changes in the time mean stationary waves are chiefly responsible for the seasonal range of this quantity at the LGM, while they only account for half the seasonal range at the present-day.

This is a preview of subscription content, access via your institution.

References

  1. Berger A, Tricot C, Gallee H, Loutre MF (1993) Water vapour, CO2 and insolation over the last glacial-interglacial cycles. In: Allen JRL, Hoskins BJ, Sellwood BW, Spicer RA, Valdes PJ (eds) Paleoclimates and their modelling. The Royal Society - Chapman and Hall, UK, pp 45–53

    Google Scholar 

  2. CLIMAP Project Members (1981) Seasonal reconstructions of the Earth's surface at the last glacial maximum. Geological Society of America Map and Chart Series, MC-36

  3. Cook KH, Held IM (1988) Stationary waves of the ice age climate. J Atmos Sci 45:807–819

    Google Scholar 

  4. Gallee H, Van Ypersele JP, Fichefet T, Tricot C, Berger A (1991) Simulation of the last glacial cycle by a coupled sectorially averaged climate-ice sheet model I: the climate model. J Geophys Res 96:13139–13161

    Google Scholar 

  5. Gleckler PJ et al. (1994) Cloud-radiative effects on implied oceanic energy transports as simulated by atmospheric general circulation models. PCMDI Rep 15, Lawrence Livermore National Laboratory, Livermore, CA

    Google Scholar 

  6. Guilderson TP, Fairbanks RG, Rubenstone JC (1994) Tropical temperature variations since 20000 years ago: modulating interhemispheric climate change. Science 263:663–665

    Google Scholar 

  7. Hall NMJ, Hoskins BJ, Valdes PJ, Senior CA (1994) Storm tracks in a high resolution GCM with doubled carbon dioxide. Q J R Meteorol Soc 120:1209–1230

    Article  Google Scholar 

  8. Hall NMJ, Valdes PJ, Dong B (1996) The maintenance of the last great ice sheets: A UGAMP GCM study. J Clim (in press)

  9. Held IM (1978) The vertical scale of an unstable baroclinic wave and its importance for eddy heat flux parametrizations. J Atmos Sci 35:572–576

    Google Scholar 

  10. Hoskins BJ, Valdes PJ (1990) On the existence of storm tracks. J Atmos Sci 47:1854–1864

    Article  Google Scholar 

  11. Hoskins BJ, Hsu HH, James IN, Masutani M, Sardeshmukh PD, White GH (1989) Diagnostics of the global atmospheric circulation. WCRP Rep 27, World Meteorological Organization, Geneva

    Google Scholar 

  12. Jousaume S (1993) Paleoclimatic tracers: an investigation using an atmospheric general circulation model under ice age conditions. Part I: desert dust. J Geophys Res 98:2767–2805

    Google Scholar 

  13. Kutzbach JE, Guetter PJ (1986) The influence of changing orbital parameters and surface boundary conditions on climate simulations for the past 18000 years. J Atmos Sci 43:1726–1759

    Article  Google Scholar 

  14. Lindzen RS, Farrell B (1980) A simple approximate result for maximum growth rate of baroclinic instabilities. J Atmos Sci 37:1648–1654

    Google Scholar 

  15. Manabe S, Broccoli AJ (1985) The influence of continental ice sheets on the climate of an ice age. J Geophys Res 90:2167–2190

    Google Scholar 

  16. Michaud R, Derome J (1991) On the mean meridional transport of energy in the atmosphere and oceans as derived from six years of ECMWF analyses. Tellus 43A:1–14

    Google Scholar 

  17. Mole N, James IN (1990) Baroclinic adjustment in a zonally varying flow. Q J R Meteorol Soc 116:247–268

    Article  Google Scholar 

  18. Peltier WR, Hyde W (1984) A model of the ice age cycle. In: Milankovitch and climate, understanding the response to orbital forcing. Berger, Imbrie, Hays, Kukla and Saltzman Eds. NATO ASI Series C vol. 126, Reidl Publ. Company, Holland, 895 pp

    Google Scholar 

  19. Rind D (1986) The dynamics of warm and cold climates. J Atmos Sci 43:3–24

    Article  Google Scholar 

  20. Rind D, Peteet D (1985) Terrestrial conditions at the last glacial maximum and CLIMAP sea-surface temperature estimates: are they consistent? Quatern Res 24:1–22

    Article  Google Scholar 

  21. Shinn RA, Barron EJ (1989) Climate sensitivity to continental ice sheet size and configuration. J Clim 2:1517–1537

    Article  Google Scholar 

  22. Simmons AJ, Hoskins BJ (1980) Barotropic influences on the growth and decay of nonlinear baroclinic waves. J Atmos Sci 37:1679–1684

    Article  Google Scholar 

  23. Slingo JM, Blackburn M, Betts A, Brugge R, Hodges K, Hoskins B, Miller M, Steenman-Clark L, Thuburn J (1994) Mean climate and transience in the tropics of the UGAMP GCM: sensitivity to convective parametrization. Q J R Meteorol Soc 20:881–922

    Google Scholar 

  24. Stocker TF, Wright DJ, Mysak LA (1992) A zonally averaged coupled ocean-atmosphere model for paleoclimate studies. J Clim 5:773–797

    Article  Google Scholar 

  25. Stone PH (1978) Baroclinic adjustment. J Atmos Sci 35:561–571

    Article  Google Scholar 

  26. Stone PH, Miller DA (1980) Empirical relations between seasonal changes in meridional temperature gradients and meridional fluxes of heat. J Atmos Sci 37:1708–1721

    Article  Google Scholar 

  27. Stone PH, Risbey JS (1990) On the limitations of general circulation models. Geophys Res Lett 17:2173–2176

    Google Scholar 

  28. Suarez M, Held IM (1979) The sensitivity of an energy balance climate model to variations in the orbital parameters. J Geophys Res 84:4825–4836

    Google Scholar 

Download references

Author information

Affiliations

Authors

Corresponding author

Correspondence to Nicholas M. J. Hall.

Rights and permissions

Reprints and Permissions

About this article

Cite this article

Hall, N.M.J., Doug, B. & Valdes, P.J. Atmospheric equilibrium, instability and energy transport at the last glacial maximum. Climate Dynamics 12, 497–511 (1996). https://doi.org/10.1007/BF02346821

Download citation

Keywords

  • Heat Flux
  • Stationary Wave
  • Last Glacial Maximum
  • Glacial Maximum
  • Storm Track