An Examination of the Sunspot Areal Dataset, 1875–2023: Paper III, The Magnetic Complexity of Sunspots

Abstract

This is the third paper in a three-part study of the sunspot areal dataset, 1875–present. Paper I (Wilson 2020) provided an overview of the areal dataset and gave some predictions for annual minimum and maximum amplitudes of specific parameters, noting that the minimum between solar cycles (SCs) 24 and 25 would likely be prolonged. Paper II (Wilson 2021) examined areal hemispheric differences, noting that SC12 had the smallest northern hemispheric annual maximum sunspot area (SSA(N)), while SC19 had the largest SSA(N), and that SC14 had the smallest southern hemispheric annual maximum sunspot area (SSA(S)), while SC18 had the largest SSA(S). Furthermore, the average time from minimum to maximum SSA was found to be about 3.8 years for SSA(N) and about 4.8 years for SSA(S). In Paper III, the magnetic complexity of sunspot groups is examined in terms of the: (1) Zurich visual classes (1875–1976), (2) Mount Wilson magnetic classes (MWC, 1982–2023), and (3) McIntosh modified Zurich visual classes (MMZ, 1982–2023). (No visual or magnetic classification of sunspot groups is available for the interval 1977–1981 in the solar areal dataset.)