Statistical Evidence for a Mid-period Change in Daily Sunspot Group Counts from August 2011 through August 2012, and the Effect on Daily Relative Sunspot Numbers (Abstract)

Volume 41 number 1 (2013)

Rodney Howe

3343 Riva Ridge Drive, Fort Collins, CO 80526; ahowe@frii.com

Abstract

(Abstract only) A combination of statistical counts modeling methods, time series analysis, and t-tests were applied to daily sunspot group counts data obtained from the American Association of Variable Star Observers (AAVSO) Solar Section. The data span the period from August 2011 through August 2012. The analysis investigates whether a statistically significant difference in daily sunspot group counts occurs between the first and second halves of this period. We show that a significant statistical difference exists between the two halves, and this difference also exists in the sunspot number. Also, the rate of change between daily sunspot group counts is shown to be stable between the two periods. These results indicate that between the two periods, the sunspot group count averages and the corresponding sunspot numbers differ, and suggests the sunspot group counts submitted by AAVSO contributors are consistent between the two periods. The change between these time periods may give insight into an apparent bi-modal clustering of sunspots and sunspot groups during this twenty-forth cycle maximum.