Journal of Physical Studies 27(2), Article 2901 [8 pages] (2023)
DOI: https://doi.org/10.30970/jps.27.2901

LATITUDINAL DISTRIBUTION OF ACTIVE REGIONS DURING SOLAR CYCLES 23–24

O. A. Baran , A. I. Prysiazhnyi 

Astronomical Observatory of Ivan Franko National University of Lviv,
8, Kyrylo & Mefodiy St., Lviv, UA–79005, Ukraine,
e-mails: oleksandra.baran@lnu.edu.ua; andrii.prysiazhnyi@lnu.edu.ua

Received 24 January 2023; in final form 24 February 2023; accepted 09 March 2023; published online 19 April 2023

We carried out a study of the latitudinal distribution of active regions (ARs) observed during solar cycles 23-24. The research was based on the ARs data from the SolarMonitor database. We supplemented this dataset with information about solar flares provided by GOES/XRS (GOES SXR Flare List).

We monitored the occurrence of ARs on the Sun and flares associated with them. Unipolar and bipolar simple ARs were observed starting from latitudes of $\pm40^{\circ}$ or even higher; bipolar complex ARs appeared mostly in the range of $\pm30^{\circ}$, where the absolute majority of the flares associated with ARs were observed. The asymmetric character of the ARs latitudinal distribution was more noticeable during the descending phase of solar activity: at the end of cycle 23 more ARs and flares occurred in the southern hemisphere, and at the end of cycle 24 they prevailed in the northern hemisphere.

We studied cyclic changes in the total values of the ARs area and peak soft X-ray flux from the flares separately in the two solar hemispheres. For both cycles, the maximum values of these parameters were observed earlier in the northern hemisphere than in the southern hemisphere.

The general behavior in the north-south asymmetry of solar activity was changed during the transition from cycle 23 to cycle 24. In cycle 23, the northern hemisphere was more active at the beginning of the ascending phase, whereas the southern hemisphere was more active in the maximum and descending phases. In cycle 24, the northern hemisphere activity dominated throughout.

Key words: active regions, magnetic complexity classes, solar flares, cycles of solar activity, north-south asymmetry.

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