Hemispheric Sunspot Number from the Madrid Astronomical Observatory for the Period 1935–1986

Autor:	M C Gallego, Víctor Manuel Sánchez Carrasco, José Manuel Vaquero, Alejandro Jesús Pérez Aparicio
Rok vydání:	2022
Předmět:	Space and Planetary Science Astronomy and Astrophysics
Zdroj:	The Astrophysical Journal. 931:52
ISSN:	1538-4357 0004-637X
DOI:	10.3847/1538-4357/ac5dc6
Popis:	Long-term studies on hemispheric asymmetry can help to understand better the solar dynamo. We present the hemispheric sunspot number calculated from daily sunspot observations made at the Madrid Astronomical Observatory for the period 1935–1986 (corresponding approximately to Solar Cycles 17–21). From this data set, we also analyzed the asymmetry index and hemispheric phase shifts. We conclude that the northern hemisphere was predominant in Solar Cycles 17–20, whereas the southern hemisphere was predominant in Solar cycle 21. The strongest asymmetries are found in Solar Cycles 20 (with a relative difference between both hemispheres of 44%) and 19 (39%). A normalization of the Madrid hemispheric sunspot number was also made with respect to the sunspot number (Version 2). Our results agree with previous studies on hemispheric asymmetry around the mid-20th century and their secular trends.
Databáze:	OpenAIRE
Externí odkaz:	https://explore.openaire.eu/search/publication?articleId=doi_________::1a4b17ff9fc2bd6db17fef3186f76b56 https://doi.org/10.3847/1538-4357/ac5dc6 Zobrazit plný text záznamu