Letter | Published:

Tropical climatic phase lags and Earth's precession cycle


The Earth's precession cycle causes changes in the seasonal cycle of incident solar radiation, affecting high-latitude and tropical climate in the period range 19–24 kyr (refs 1–3). Atmospheric general circulation models (GCMs) have shown that thermally forced monsoon circulations are enhanced by the strengthened seasonal cycle of solar heating that results when summer solstice occurs near perihelion4,5. However, observations indicate that the tropical climatic response reaches a maximum thousands of years after solstice–perihelion alignment2,6. Because the GCM experiments included slowly evolving boundary conditions (such as ice sheet extent and surface albedo), whose influences on tropical climate are not well understood, reasons for the observed lag are unclear. We have addressed this uncertainty by examining the response to the precession cycle. Our model suggests that some features of the monsoon circulation may reach maximum intensity 3,000 yr after solstice–perihelion alignment as the result of a direct thermal response to the astronomical forcing.

Access optionsAccess options

Rent or Buy article

Get time limited or full article access on ReadCube.


All prices are NET prices.


  1. 1

    Hays, J. D., Imbrie, J. & Shackelton, N. J. Science 194, 1121–1132 (1976).

  2. 2

    Prell, W. L. in Milankovitch and Climate Pt 1 (eds Berger, A. L. et al.) 349–366 (Reidel, Dordrecht, 1984).

  3. 3

    Berger, A. L. J. atmos. Sci. 35, 2362–2367 (1978).

  4. 4

    Kutzbach, J. E. & Guetter, P. J. in Milankovitch and Climate Pt 2 (eds Berger, A. L. et al.) 801–820 (Reidel, Dordrecht, 1984).

  5. 5

    Kutzbach, J. E. & Street-Perrott, F. A. Nature 317, 130–134 (1985).

  6. 6

    Street, F. A. & Grove, A. T. Quat. Res. 12, 83–118 (1979).

  7. 7

    North, G. R., Mengel, J. G. & Short, D. A. J. geophys. Res. 88, 6576–6586 (1983).

  8. 8

    Crowley, T. J., Short, D. A., Mengel, J. G. & North, G. R. Science 231, 579–584 (1986).

  9. 9

    Ruddiman, W. F. & McIntyre, A. Science 212, 617–627 (1981).

  10. 10

    Porter, S. C. Quat. Res. 16, 263–292 (1981).

Download references

Author information

Rights and permissions

Reprints and Permissions

About this article

Further reading


By submitting a comment you agree to abide by our Terms and Community Guidelines. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate.