Multiperiodic irradiance changes caused by r-modes and g-modes

• Published in: Solar physics Vol. 109; no. 1, 19; pp. 1 - 18
• Main Authors: Wolff, Charles L., Hickey, John R.
• Format: Journal Article
• Language: English
• Published: Legacy CDMS Reidel 01.01.1987
• Subjects: Astronomy; Earth, ocean, space; Exact sciences and technology; Other topics on the solar system; Solar Physics; Solar system; Solar radiation
• ISSN: 0038-0938; 1573-093X
• DOI: 10.1007/BF00167395

More than 20 real periodicities ranging from 20 days to 2 years modulate the solar irradiance data accumulated since November 1978 by Nimbus 7. Many are quite strong during the first three years (solar maximum) and weak after that. There is a high correspondence between periods in irradiance and 28 periods predicted from the rotation and beating of global solar oscillations (r-modes and g-modes). Angular states l = 1, 2, and 3 are detected as well as some unresolved r-mode power at higher l. The prominence of beat periods implies a nonlinear system whose effective nonlinear power was measured to be about 2. This analysis constitutes a detection of r-modes in the sun, and determines from them a mean sidereal rotation rate for the convective envelope of 459 + or - 4 nHz which converts to a period of 25.2 days (27.1d, synodic).