Properties of sunspot cycles and hemispheric wings since the 19th century

Abstract

Aims. The latitudinal evolution of sunspot emergence over the course of the solar cycle, the so-called butterfly diagram, is a fundamental property of the solar dynamo. Here we present a study of the butterfly diagram of sunspot group occurrence for cycles 7–10 and 11–23 using data from a recently digitized sunspot drawings by Samuel Heinrich Schwabe in 1825–1867, and from RGO/USAF/NOAA(SOON) compilation of sunspot groups in 1874–2015.