HR: 11:00h
AN: SH22B-02    [Abstracts]
TI: Can Changing Sunspot and Facular Areas Reproduce the Amplitude of Total Irradiance Variations?(Look,Mom; No Free Parameters!)
AU: * Foukal, P
EM: pfoukal@world.std.com
AF: Heliophysics,Inc, 192 Willow Rd, Nahant, MA 01908 United States
AU: Bernasconi, P N
EM: pietro.bernasc@jhuapl.edu
AF: Johns Hopkins Univ APL, 11100 Johns Hopkins Rd, Laurel, MD 20723 United States
AU: Walton, S R
EM: stephen.walton@csun.edu
AF: Cal State Univ., Northridge, 18111 Nordhoff St, Northridge, CA 91330 United States
AB: Empirical models of total solar irradiance variation demonstrate a high correlation between observed irradiance fluctuations and the changing areas of spots and faculae. However, the contrast of these structures (especially the faculae) in integrated light is still uncertain. Consequently, the agreement in amplitude of the measured and modeled irradiance time series remains poorly known. Recently, the first measurements of facular contrast in broad - band integrated light were obtained using the balloon -borne Solar Bolometric Imager (Foukal et al., Ap.J. Letts 611,57,2004). These measurements, obtained over approximately the same wavelength range accepted by radiometers such as VIRGO or ACRIM, enable the first reconstruction of the total irradiance expected from spots and faculae, with no free parameters. We compare this reconstruction with the radiometric record to determine whether other contributions besides the darkness of spots and brightness of faculae are required to explain solar irradiance variation, at least over rotational time scales.
DE: 7524 Magnetic fields
DE: 7537 Solar and stellar variability
DE: 7538 Solar irradiance
SC: SPA-Solar and Heliospheric Physics [SH]
MN: 2005 Joint Assembly