Confronting a solar irradiance reconstruction with solar and stellar data (Research Note)

• Published in: Astronomy and astrophysics (Berlin) 2012-08, Vol.544, p.1-1
• Main Authors: Judge, P G, Lockwood, G W, Radick, R R, Henry, G W, Shapiro, A I, Schmutz, W, Lindsey, C
• Format: Article
• Language: English
• Subjects: Indexing in process
• ISSN: 0004-6361; 1432-0746

A recent paper by Shapiro and colleagues reconstructs spectral and total irradiance variations of the Sun during the holocene. In this note, the authors comment on why their methodology leads to large variations in the solar TSI on century-long time scales, in stark contrast to other reconstructions which have ...0.1% variations. Shapiro et al's large amplitudes arise from differences between the irradiances computed from models A and C of Fontenla and colleagues, and from their explicit assumption that the radiances of the quiet Sun vary with the cosmic ray modulation potential. The authors suggest that the upper photosphere, as given by model A, is too cool, and discuss relative contributions of local vs global dynamos to the magnetism and irradiance of the quiet Sun. By adopting model A, Shapiro et al have over-estimated quiet-Sun irradiance variations by about a factor of two, based upon a re-analysis of sub-mm data from the James Clerk Maxwell telescope. (ProQuest: ... denotes formulae/symbols omitted.)