The Phase Shifts of the Paired Wings of Butterfly Diagrams

TL;DR

This paper investigates the asynchronous latitudinal migration and phase shifts between the paired wings of butterfly diagrams for sunspot groups and solar filaments, revealing hemispherical asymmetries and their implications for solar activity cycles.

Contribution

It provides new insights into the phase relationships and asymmetries of solar activity indicators across hemispheres over more than a century.

Findings

Latitudinal migration occurs asynchronously in hemispheres.

Paired wings of butterfly diagrams exhibit spatial asymmetry.

Phase shifts relate to hemispheric solar activity strength.

Abstract

Sunspot groups observed by Royal Greenwich Observatory/US Air Force/NOAA from May 1874 to November 2008 and the Carte Synoptique solar filaments from March 1919 to December 1989 are used to investigate the relative phase shift of the paired wings of butterfly diagrams of sunspot and filament activities. Latitudinal migration of sunspot groups (or filaments) does asynchronously occur in the northern and southern hemispheres, and there is a relative phase shift between the paired wings of their butterfly diagrams in a cycle, making the paired wings spatially asymmetrical on the solar equator. It is inferred that hemispherical solar activity strength should evolve in a similar way within the paired wings of a butterfly diagram in a cycle, making the paired wings just and only keep the phase relationship between the northern and southern hemispherical solar activity strengths, but a relative phase shift between the paired wings of a butterfly diagram should bring about an almost same relative phase shift of hemispheric solar activity strength.