Online Catalog

GCRIO Home ->arrow Library ->arrow Consequences -> arrow Vol. 2, No. 1, Winter 1996 -> arrow The Sun and Climate -> arrow Figure 2 Search
U.S. Global Change Research Information Office logo and link to home
Updated 11 November 2004

Consequences Vol. 2, No. 1, Winter 1996








Figure 2 Variations in solar total radiation incident on the Earth, in watts per square meter, on different time scales. (a) Recorded, day-to-day changes for a period of seven months at a time of high solar activity. The largest dips, of up to 0.3%, persist for about a month and are the result of large sunspot groups that are carried across the face of the Sun with solar rotation. (b) Observed changes for the fifteen-year period over which direct measurements have been made, showing the 11-year (Schwabe) cycle of amplitude about 0.1 percent. (c) A reconstruction of variations in solar radiation since about 1600, based on historical records of sunspot numbers and postulated solar surface brightness during the 70-year Maunder Minimum. Estimated variations are of larger amplitude than have yet been observed. (d) A longer record of solar activity based on postulated changes in solar radiation that are derived from measured variations in 14C and 10Be.

U.S. Global Change Research Information Office, Suite 250, 1717 Pennsylvania Ave, NW, Washington, DC 20006. Tel: +1 202 223 6262. Fax: +1 202 223 3065. Email: . Web: Webmaster: .
U.S. Climate Change Technology Program Intranet Logo and link to Home