An Optical Analysis of Sunspots as Predictors of Geomagnetic Storms

TL;DR

This study investigates how optical properties of sunspots can predict severe geomagnetic storms on Earth by analyzing correlations between sunspot characteristics and geomagnetic activity indices.

Contribution

It introduces a correlation analysis between sunspot intrinsic features and geomagnetic storm severity, highlighting the predictive potential of sunspot total intensity.

Findings

Significant correlation between sunspot total intensity and geomagnetic storm severity.

R-Squared of 0.690 with all data, improving to 0.855 after removing a corrupted data point.

Sunspot characteristics can serve as predictors for geomagnetic storm strength.

Abstract

Although a variety of phenomena may create a geomagnetic storm on Earth, the most severe geomagnetic storms arise from solar activity, and in particular, coronal mass ejections (CMEs) and solar flares. CMEs and flares originate primarily from sunspots. The "aa index" is a metric which ranks all of the strongest geomagnetic storms between 1868 and 2010 based on a variety of characteristics taken from several sources. This paper examines correlations between the aa index of the most severe geomagnetic storms and the intrinsic characteristics of the sunspots from which they originated. We find a correlation between the total rank of the aa index of the storms and the "total intensity" of the sunspot, where total intensity is defined as the sunspot's mean intensity multiplied by its area. The correlation has an R-Squared = 0.690 and R-Squared = 0.855 when a potentially corrupted data point is removed.