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.

Science 13 May 1988:
Vol. 240. no. 4854, pp. 906 - 908
DOI: 10.1126/science.240.4854.906
Prev | Table of Contents | Next

Articles

A Model of Solar Luminosity Modulation by Magnetic Activity Between 1954 and 1984

J. LEAN 1 and P. FOUKAL 2

1 Applied Research Corporation, Landover, MD 20785.
2 Cambridge Research and Instrumentation, Inc., Cambridge, MA 02139.

A simple model based on the changes in excess radiation from bright magnetic faculae and on changes in reduced radiation from dark spots is remarkably successful in matching the slow variations of total solar irradiance measured simultaneously by the ERB and ACRIM satellite radiometers between 1981 and 1984. This model was extended back to 1954 to reconstruct the modulation of irradiance by magnetic activity during the past three 11-year solar cycles. The model predicts that the sun is consistently brighter at activity maximum than at minimum. The 0.07 percent brightening at the peak of the last cycle in 1980 was more pronounced than the brightenings found for either of the two previous cycles, even though cycle 19, which peaked around 1957, had the largest sunspot number amplitude in the history of reliable sunspot records.

Submitted on December 28, 1987
Accepted on March 30, 1988


THIS ARTICLE HAS BEEN CITED BY OTHER ARTICLES:
An Empirical Model of Total Solar Irradiance Variation Between 1874 and 1988.
P. Foukal and J. Lean (1990)
Science 247, 556-558
   Abstract »    PDF »
Contribution of Ultraviolet Irradiance Variations to Changes in the Sun's Total Irradiance.
J. LEAN (1989)
Science 244, 197-200
   Abstract »    PDF »


To Advertise     Find Products

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