An alternative measure of solar activity from detailed sunspot datasets

Muraközy, Judit and Baranyi, Tünde and Ludmány, András (2016) An alternative measure of solar activity from detailed sunspot datasets. SOLAR PHYSICS, 291 (9-10). pp. 2941-2950. ISSN 0038-0938

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Abstract

The sunspot number is analyzed by using detailed sunspot data, including aspects of observability, sunspot sizes, and proper identification of sunspot groups as discrete entities of the solar activity. The tests show that besides the subjective factors there are also objective causes of the ambiguities in the series of sunspot numbers. To introduce an alternative activity measure the physical meaning of the sunspot number has to be reconsidered. It contains two components whose numbers are governed by different physical mechanisms, this is one source of the ambiguity. This article suggests an activity index, which is the amount of emerged magnetic flux. The only long-term proxy measure is the detailed sunspot area dataset with proper calibration to the magnetic flux amount. The Debrecen sunspot databases provide an appropriate source for the establishment of the suggested activity index.

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