The north-south asymmetry of active regions of different magneto-morphological types in solar cycles 23 and 24

Zhukova, A. V.; Sokoloff, Dmitry; Abramenko, V. I.; Khlystova, A. I.

doi:10.1016/j.asr.2022.09.013

Cited by 6 publications

(14 citation statements)

References 66 publications

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“…The N-S asymmetry indices of the prominence number, the cumulative prominence area, the AR number, and the cumulative AR area indicate that the northern hemisphere is the dominant hemisphere in solar cycle 24, which is in accord with the results for sunspots, magnetic morphological classifications of ARs and filaments (Hao et al 2015;Chowdhury et al 2019;Veronig et al 2021;Chandra et al 2022;Zhukova et al 2023). The indices for the low-latitude prominences have the same trend.…”

Section: Discussionsupporting

confidence: 84%

Statistical Analyses of Solar Prominences and Active Region Features in 304 Å Filtergrams Detected via Deep Learning

Zhang,

Hao,

Chen

2024

ApJS

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Solar active regions (ARs) are areas on the Sun with very strong magnetic fields where various activities take place. Prominences are one of the typical solar features in the solar atmosphere, whose eruptions often lead to solar flares and coronal mass ejections. Therefore, studying their morphological features and their relationship with solar activity is useful in predicting eruptive events and in understanding the long-term evolution of solar activities. A huge amount of data have been collected from various ground-based telescopes and satellites. The massive amounts of data make human inspection difficult. For this purpose, we developed an automated detection method for prominences and ARs above the solar limb based on deep-learning techniques. We applied it to process the 304 Å data obtained by SDO/AIA from 2010 May 13 to 2020 December 31. Besides the butterfly diagrams and latitudinal migrations of the prominences and ARs during solar cycle 24, the variations of their morphological features (such as the locations, areas, heights, and widths) with the calendar years and the latitude bands were analyzed. Most of these statistical results based on our new method are in agreement with previous studies, which also guarantees the validity of our method. The N–S asymmetry indices of the prominences and ARs show that the northern hemisphere is the dominant hemisphere in solar cycle 24, except for 2012–2015, and 2020 for ARs. The high-latitude prominences show much stronger N–S asymmetry, where the northern hemisphere is dominant in ∼2011 and ∼2015, and the southern hemisphere is dominant from 2016–2019.

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Section: Discussionsupporting

confidence: 84%

Statistical Analyses of Solar Prominences and Active Region Features in 304 Å Filtergrams Detected via Deep Learning

Zhang,

Hao,

Chen

2024

ApJS

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“…2), что потоки нерегулярных АО особенно выражены в S-полушарии. Причиной может быть ослабление тороидального поля в одном из полушарий из-за взаимодействия дипольной и квадрупольной составляющих [6]. Дело в том, что силовые линии диполя и квадруполя имеют одинаковое направление в одном из полушарий и противоположно направлены в другом.…”

Section: рисunclassified

“…Все АО, помимо одиночных пятен, были распределены между двумя классами: регулярные АО (биполярные группы, выполняющие закон полярностей Хейла, закон Джоя, правило о доминировании лидирующего пятна) [3,4] и нерегулярные АО (все остальные). Ранее мы уже исследовали N-S асимметрию количества регулярных и нерегулярных АО [5,6]. Здесь мы сравниваем данные о количестве и магнитном потоке АО.…”

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Cyclic Variations of the Regular and Irregular Active Regions in the N- And S- Hemispheres in Solar Cycles 23 and 24

Zhukova

2023

Proceedings of the 27th All-Russia Conference on Solar and Solar-Terrestrial Physics

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The redesigned catalog of magneto-morphological classes (MMC) of active regions (ARs) CrAO (https://sun.crao.ru/databases/catalog-mmc-ars) was used to study 3047 ARs from May 1996 to December 2021. All ARs, except for unipolar spots, were divided into regular ARs (bipolar groups obeying the Hale's polarity law, the Joy's law and the rule of the leading sunspot dominance) and irregular ARs (all others). The analysis of the number and flux data showed the following. For ARs of each MMC type, the trends for the number and fluxes are similar. However, for fluxes, all the features of time profiles are more pronounced. The mutual position of the number and flux profiles depends on the strength of the cycle and the level of activity in each of the cycle maxima. Although the number of the irregular ARs is smaller than the number of regular groups, their fluxes are comparable. In each of the hemispheres, for ARs of each MMC type, the number and flux profiles demonstrate a multi-peak structure. Some peaks coincide with one of the two main maxima of the solar cycle. The second maximum is mainly formed by the irregular ARs in the S-hemisphere. The predominance of the irregular ARs fluxes in one of the hemispheres might be due to the interaction of the dipole and quadrupole components of the global magnetic field.

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“…1) и нерегулярных (рис. 2) АО с данными USAF/NOAA Solar Region Summury для всех АО цикла показало, что АО каждого из классов образуют пики в двух максимумах цикла в разных полушариях не одновременно (достигают максимумов иногда в фазе, а иногда -в противофазе с общим числом солнечных пятен), что согласуется с результатами работы [3].…”

Section: Doi: 1031725/0552-5829-2022-103-106unclassified

Methods for Determining the Statistical Significance of the Observed North-South Asymmetry of the Active Regions

Zhukova¹

2022

Proceedings of the 26th All-Russia Conference on Solar and Solar-Terrestrial Physics

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Statistical studies of 2046 active regions (ARs) of the solar cycle 23 and 1507 ARs of the solar cycle 24 were carried out using the catalog of magneto-morphological classes of ARs CrAO (https://sun.crao.ru/databases/catalog-mmc-ars). All ARs, except for unipolar spots, were divided into regular (obeying the Hale's polarity law, the Joy's law and the rule of the leading sunspot dominance) and irregular ARs (all others). The study of cyclic variations showed that the ARs of each type form peaks in two maxima of the cycle in different hemispheres not simultaneously (they reach maxima sometimes in-phase, and sometimes outof-phase with a total number of sunspots). We used the normal approximation to a binomial distribution and the Pearson's χ-square test to determine the level of statistical significance of the results obtained relatively north-south asymmetry of ARs for each of the two maxima of each of the cycles for each type of ARs. In four of the eight cases studied, we found a high level of statistical significance of the observed north-south asymmetry, in one -a marginal level, which allows us to confirm the statistical significance of the observed phenomenon as a whole.

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The north-south asymmetry of active regions of different magneto-morphological types in solar cycles 23 and 24

Cited by 6 publications

References 66 publications

Statistical Analyses of Solar Prominences and Active Region Features in 304 Å Filtergrams Detected via Deep Learning

Statistical Analyses of Solar Prominences and Active Region Features in 304 Å Filtergrams Detected via Deep Learning

Cyclic Variations of the Regular and Irregular Active Regions in the N- And S- Hemispheres in Solar Cycles 23 and 24

Methods for Determining the Statistical Significance of the Observed North-South Asymmetry of the Active Regions

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