Note to users. If you're seeing this message, it means that your browser cannot find this page's style/presentation instructions -- or possibly that you are using a browser that does not support current Web standards. Find out more about why this message is appearing, and what you can do to make your experience of our site the best it can be.

Site Tools

  • AAAS
  • Subscribe
  • Feedback

Site Search

Search Advanced

Science 7 April 1995:
Vol. 268. no. 5207, pp. 59 - 68
DOI: 10.1126/science.268.5207.59
Prev | Table of Contents | Next

Articles

The Seasons, Global Temperature, and Precession

David J. Thomson 1

1 AT&T Bell Labs, Murray Hill, NJ 07974, USA.

Analysis of instrumental temperature records beginning in 1659 shows that in much of the world the dominant frequency of the seasons is one cycle per anomalistic year (the time from perihelion to perihelion, 365.25964 days), not one cycle per tropical year (the time from equinox to equinox, 365.24220 days), and that the timing of the annual temperature cycle is controlled by perihelion. The assumption that the seasons were timed by the equinoxes has caused many statistical analyses of climate data to be badly biased. Coherence between changes in the amplitude of the annual cycle and those in the average temperature show that between 1854 and 1922 there were small temperature variations, probably of solar origin. Since 1922, the phase of the Northern Hemisphere coherence between these quantities switched from 0° to 180° and implies that solar variability cannot be the sole cause of the increasing temperature over the last century. About 1940, the phase patterns of the previous 300 years began to change and now appear to be changing at an unprecedented rate. The average change in phase is now coherent with the logarithm of atmospheric CO2 concentration.

Submitted on January 4, 1995
Accepted on March 3, 1995


THIS ARTICLE HAS BEEN CITED BY OTHER ARTICLES:
Classics in physical geography revisited.
P. D. Jones (1999)
Progress in Physical Geography 23, 425-428
   PDF »
Dependence of global temperatures on atmospheric CO2 and solar irradiance.
D. J. Thomson (1997)
PNAS 94, 8370-8377
   Abstract »    Full Text »    PDF »
Testing for Bias in the Climate Record.
O. R. White, W. Mende, and J. Beer (1996)
Science 271, 1880-1881
   PDF »
Response: Testing for Bias in the Climate Record.
D. J. Thomson (1996)
Science 271, 1881-1883
   PDF »


To Advertise     Find Products

Science. ISSN 0036-8075 (print), 1095-9203 (online)