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Two-parameter model of total solar irradiance variation over the solar cycleTotal solar irradiance measured by the SMM/ACRIM radiometer is modelled from the Photometric Sunspot Index and the Mg II core-to-wing ratio with multiple regression analysis. Considering that the formation of the Mg II line is very similar to that of the Ca II K line, the Mg II core-to-wing ratio, measured by the Nimbus-7 and NOAA9 satellites, is used as a proxy for the bright magnetic elements, including faculae and the magnetic network. It is shown that the relationship between the variations in total solar irradiance and the above solar activity indices depends upon the phase of the solar cycle. Thus, a better fit between total irradiance and its model estimates can be achieved if the irradiance models are calculated for the declining portion and minimum of solar cycle 21, and the rising portion of solar cycle 22, respectively. There is an indication that during the rising portion of solar cycle 22, similar to the maximum time of solar cycle 21, the modelled total irradiance values underestimate the measured values. This suggests that there is an asymmetry in the long-term total irradiance variability.
Document ID
19930071114
Acquisition Source
Legacy CDMS
Document Type
Conference Paper
Authors
Pap, Judit M.
(Jet Propulsion Lab., California Inst. of Tech. Pasadena, CA, United States)
Willson, Richard C.
(JPL Pasadena, CA, United States)
Donnelly, Richard F.
(NOAA, Space Environment Lab. Boulder, CO, United States)
Date Acquired
August 16, 2013
Publication Date
January 1, 1991
Publication Information
Publication: In: The solar cycle; Proceedings of the National Solar Observatory(Sacramento Peak 12th Summer Workshop, Sunspot, NM, Oct. 15-18, 1991
Publisher: Astronomical Society of the Pacific (ASP Conference Series. Vol. 27)
ISSN: 0004-6280
Subject Category
Solar Physics
Accession Number
93A55111
Distribution Limits
Public
Copyright
Other

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