The shape of sunspots and solar activity cycles

TL;DR

This study analyzes sunspot shapes over multiple solar cycles, revealing that their elongation correlates with the amplitude of subsequent activity cycles, with sunspots generally being ellipsoid and inclined relative to the equator.

Contribution

It introduces a method for analyzing sunspot shapes and uncovers a relationship between sunspot elongation and future solar cycle strength.

Findings

Sunspots are predominantly ellipsoid with a major axis inclined to the equator.

The inclination of sunspot axes varies between hemispheres and correlates with bipole orientations.

Elongation of sunspots along the current cycle's longitude predicts higher next cycle activity.

Abstract

The paper presents the results of the analysis of the geometric characteristics of sunspots for the period of 19-24 cycles of activity. The shape of sunspots was studied on the basis of the method of normalization of images of sunspots to study the average profile of the spot. The deviation of the shape of sunspots from the axisymmetric configuration is investigated. It was found that the spots, as a rule, have an ellipsoid shape, and the major axis of the ellipse has a predominant inclination to the equator, opposite in the Northern and Southern hemispheres. The angle of inclination of the sunspot axis corresponds to the angle of inclination of the bipoles in the activity cycles. The relationship between the shape of sunspots in the current cycle and the amplitude of the next cycle of activity is found. The greater the elongation along the longitude of the current cycle of spots, the higher the next cycle of activity will be.