AAVSO: American Association of Variable Star Observers

Comparison of North-South Hemisphere Data from AAVSO Visual Observers and the SDO Satellite Computer-Generated Wolf Numbers (Abstract)

Volume 47 number 1 (2019)

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


(Abstract only) Rolling correlations and rolling covariance analysis are used for two different type data submitted to the AAVSO solar database. In this paper we look at rolling correlations from 35 visual solar observers and their Wolf numbers for north and south solar hemispheres, and compare those data with SDO (Solar Dynamics Observatory) satellite Wolf numbers calculated from HMI CCD images of north-south magnetograms and visual intensity CCD images (http://hmi.stanford.edu). The SDO computer generated group, sunspot, and Wolf numbers from HMI images show symmetric volatility in the plots when compared to the AAVSO solar observers who count group, sunspot, and Wolf numbers from observatories on Earth. Rolling correlation can be used to examine how correlative relationships between the two solar hemisphere Wolf numbers change over time. A value of 1 means both hemispheres are synchronized with each other. A value of –1 means that if one hemisphere’s Wolf numbers decline, the other hemisphere’s numbers rise. A correlation of zero means no correlation relationship exists.