Solar Cycle 24: Curious Changes in the Relative Numbers of Sunspot Group Types

Kılçık, Ali; Yurchyshyn, Vasyl; Özgüç, A.; Rozelot, J. P.

doi:10.1088/2041-8205/794/1/l2

Cited by 29 publications

(24 citation statements)

References 6 publications

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“…They found that the number of large groups peaked about two years later than small ones except for solar cycle 22 (1986)(1987)(1988)(1989)(1990)(1991)(1992)(1993)(1994)(1995)(1996): the difference between large and small SG numbers is very prominent during solar cycle 23, while maxima were almost flat during solar cycle 21 and 22. Recently, Kilcik et al (2014) analyzed the sunspot counts (SSCs) in four categories, as small, medium, large and final, from 1982 to 2014, and found similar results for SSCs. Here, we analyzed monthly median f 0 F 1 and f 0 F 2 for 1976 -2015 time interval which include this anomalous solar cycle 23 (1996)(1997)(1998)(1999)(2000)(2001)(2002)(2003)(2004)(2005)(2006)(2007)(2008) and which clearly reveals that during solar cycle 23 the f 0 F 1 is following the temporal variation of SSGN, while the f 0 F 2 is following the LSGN.…”

Section: Discussionmentioning

confidence: 88%

Critical frequencies of the ionospheric F1 and F2 layers during the last four solar cycles: Sunspot group type dependencies

Yiğit

Kılçık

Elı́as

et al. 2018

Journal of Atmospheric and Solar-Terrestrial Physics

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The long term solar activity dependencies of ionospheric F 1 and F 2 regions' critical frequencies (f 0 F 1 and f 0 F 2 ) are analyzed for the last four solar cycles . We show that the ionospheric F 1 and F 2 regions have different solar activity dependencies in terms of the sunspot group (SG) numbers: F 1 region critical frequency (f 0 F 1 ) peaks at the same time with the small SG numbers, while the f 0 F 2 reaches its maximum at the same time with the large SG numbers, especially during the solar cycle 23. The observed differences in the sensitivity of ionospheric critical frequencies to sunspot group (SG) numbers provide a new insight into the solar activity effects on the ionosphere and space weather. While the F 1 layer is influenced by the slow solar wind, which is largely associated with small SGs, the ionospheric F 2 layer is more sensitive to Coronal Mass Ejections (CMEs) and fast solar winds, which are mainly produced by large SGs and coronal holes. The SG numbers maximize during of peak of the solar cycle and the number of coronal holes peaks during the sunspot declining phase. During solar minimum there are relatively less large SGs, hence reduced CME and flare activity. These results provide a new perspective for assessing how the different regions of the ionosphere respond to space weather effects.where f is the number of individual spots, g is the number of observed sunspot groups, and k is a correction factor for each observatory. The sunspot number is the best known and the longest solar activity index and is a good proxy for the solar activity variations (Clette et al. 2014;Hathaway 2015). These variations can also be represented by other solar activity indicators, such as, sunspot areas (SSAs), sunspot group (SG) numbers, total solar irradiance (TSI), and 10.7 cm solar radio flux (F 10.7 ). The solar activity variations obtained from these indicators show small differences in time, depending on the description of indices and also the background physical

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Section: Discussionmentioning

confidence: 88%

Critical frequencies of the ionospheric F1 and F2 layers during the last four solar cycles: Sunspot group type dependencies

Yiğit

Kılçık

Elı́as

et al. 2018

Journal of Atmospheric and Solar-Terrestrial Physics

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“…In the minimum between cycles 23 and 24 the contribution of sunspot in small groups to the total number of sunspots was a factor of 7 to 8 higher than that of sunspots in large groups. Kilcik et al (2011Kilcik et al ( , 2014, based on data from Learmonth Observatory, showed that different types of sunspots and groups of sunspots behave differently over a solar cycle, and their relative abundance varies from cycle to cycle. Here we confirm and expand this result for two more observatories: Holloman and San Vito.…”

Section: Resultsmentioning

confidence: 99%

“…Using data for the four most recent solar cycles, Kilcik et al (2014) separated active regions into four types, based on the size of the sunspot group and the sunspot evolution:…”

Section: Methodsmentioning

confidence: 99%

“…The data were processed in the following way: First, we separated sunspot groups into the four categories S, M, L, and F according the classification of Kilcik et al (2014), and calculated the daily total number of sunspot groups (SSGs) and the sunspot counts (SSCs) for each category. Then we calculated monthly averages from the daily numbers for those categories, thus obtaining monthly values, essentially independent of data gaps.…”

Section: Methodsmentioning

confidence: 99%

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The Ratio Between the Number of Sunspot and the Number of Sunspot Groups

et al. 2017

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Abstract⎯Data from three solar observatories (Learmonth, Holloman, and San Vito) are used to study the variations in the average number of sunspots per sunspot group. It is found that the different types of sunspot groups and the number of sunspots in these groups have different solar cycle and cycle to cycle variations. The varying ratio between the average number of sunspots and the number of sunspot groups is shown to be a real feature and not a result of changing observational instruments, observers' experience, calculation schemes, etc., and is a result of variations in the solar magnetic fields. Therefore, the attempts to minimize the discrepancies between the sunspot number and sunspot group series are not justified, and lead to the loss of important information about the variability of the solar dynamo.

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“…Sunspots, which happen in photosphere, is the basic signal of solar activity. Relative number of sunspots is the most common and fundamental parameter which depicts the intensity of solar activity [15]. According to the definition given by R. Wolf in 1848, relative number of sunspots, which is also known as the Zurich number, is determined by the equation given below:…”

Section: Analysis On the Joint Effects Of Solar Activity And Atmosphementioning

confidence: 99%

Analysis of Solar Activity and Atmospheric Pressure Competition Effects on Cosmic Radiation Events

2020

Can. J. Phys.

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In this paper, we analyze the influence of characteristic solar activity parameters as well as the competition effects in solar activity and atmospheric pressure on the records of cosmic radiation based on HiSPARC, a ground-based detector monitoring secondary cosmic ray intensity. We gather the data from No.501 HiSPARC station situated at Nikhef in Science Park, Amsterdam, Netherlands (52. 3558963°N, 4.9509827°E, 56.18 m of altitude). From the anticorrelation between the number of solar flares, relative number of sunspots and that of events, we obtain the formula through an exponential fitting model. Furthermore, we quantitatively find the correlation between the daily average number of cosmic ray events and the characteristic solar activity parameters, including the number, the area and the latitude of sunspot groups within one month. Turning to the combined effects of solar activity and atmospheric pressure, we calculate the critical interval, beyond which the influence of solar activity on the number of events is weaker.

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Solar Cycle 24: Curious Changes in the Relative Numbers of Sunspot Group Types

Cited by 29 publications

References 6 publications

Critical frequencies of the ionospheric F1 and F2 layers during the last four solar cycles: Sunspot group type dependencies

Critical frequencies of the ionospheric F1 and F2 layers during the last four solar cycles: Sunspot group type dependencies

The Ratio Between the Number of Sunspot and the Number of Sunspot Groups

Analysis of Solar Activity and Atmospheric Pressure Competition Effects on Cosmic Radiation Events

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