Asymmetry of Sunspot Distribution in Solar Cycles 12–24 and the Gnevyshev–Ohl Rule

The nonaxisymmetric component of the sunspot distribution (longitudinal asymmetry) is considered based on the Greenwich–USAF/NOAA data for 1874–2016. Vector summation was used to estimate the value of longitudinal asymmetry. The asymmetry vector modulus characterizes the asymmetry value, whereas the vector phase indicates the active longitude. The longitudinal asymmetry changes with the 11-year cycle of solar activity. It is shown that, in contrast to the solar activity, which obeys the Gnevyshev–Ohl rule (the even cycle is lower than the following odd cycle), only the first pair in the longitudinal asymmetry from each quad of cycles (from cycle 12 to 23) observed the Gnevyshev–Ohl rule, while the following pair conformed to the antirule, i.e., the even cycle was higher than the following odd cycle. This is probably a manifestation of the 44-year periodicity in the nonaxisymmetric component.