Solar irradiance variability: a six-year comparison between SORCE observations and the SATIRE model W. T. Ball, Y. C. Unruh, N. A. Krivova, S. Solanki and J. W. Harder A&A, 530 (2011) A71 Published online: 12 May 2011 DOI: 10.1051/0004-6361/201016189