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Automatic Inflation in the AAVSO Sunspot Number

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Bradley E. Schaefer

Physics Deparment, JWG 463

Yale University

New Haven, CT 06520-8121

Presented at the 85th AAVSO Annual Meeting, November 2, 1996

Abstract

The AAVSO sunspot number has a subtle mathematical flaw in its procedure which automatically inflates the reported number every time the K-coefficients are recalculated. This will result in a slow and spurious rise in apparent solar activity. This inflation is roughly 0.3% per recalculation, and the K-coefficients have been changed ~18 times since the founding of the AAVSO Sunspot Program in 1944. Thus, the current inflation is ~6%, and it will become exponentially worse with time. While the effect is now small enough not to be prominent, it causes the apparent level of solar activity to increase with time. This increase contributes to the confusion surrounding the issue of the detection of global warming due to greenhouse gases. Thus, the old AAVSO numbers must be retroactively corrected and procedures implemented that are free of inflation.