Forecast of Maximum Sunspot Number of Cycle 24

Sunspots are temporary phenomena on the photosphere of the Sun which appear visibly as dark spots compared to surrounding regions. Sunspot populations usually rise fast but fall more slowly when observed for any particular solar cycle. The sunspot numbers for the current cycle 24 and the previous three cycles have been plotted for duration of first four years for each of them. It appears that the value of peak sunspot number for solar cycle 24 is smaller than the three preceding cycles. When regression analysis is made it exhibits a trend of slow rising phase of the cycle 24 compared to previous three cycles. Our analysis further shows that cycle 24 is approaching to a longer-period but with smaller occurrences of sunspot number.

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The Impact of Sunspots Number on Critical Frequencies foF2 for the IONOSPHERIC Layer-F2 Over Erbil Station During the Down Phase of Solar Cycle 24

NeuroQuantology ◽

10.14704/nq.2021.19.8.nq21128 ◽

2021 ◽

Vol 19 (8) ◽

pp. 157-168

Author(s):

Wafaa H.A. Zaki

Keyword(s):

Solar Activity ◽

Solar Cycle ◽

Sunspot Number ◽

Critical Frequency ◽

Radio Communication ◽

Ionospheric Layer ◽

Solar Cycle 24 ◽

Critical Frequency Fof2 ◽

Cycle 24 ◽

The Impact

The ionosphere layer (F2) is known as the most important layer for High frequency (Hf) radio communication because it is a permanent layer and excited during the day and night so it is able to reflect the frequencies at night and day due to its high critical frequency, and this layer is affected by daily and monthly solar activity. In this study the characteristics and behavior of F2 layer during Solar cycle 24 were studied, the effect of Sunspots number (Ri) on the critical frequency (foF2), were investigated for the years (2015, 2016, 2017, 2018, 2019, 2020) which represents the down phase of the solar cycle 24 over Erbil station (36° N, 44° E) by finding the critical frequency (foF2) values, the layer’ s impression times are determined for the days of solstice as well as equinox, where the solar activity was examined for the days of the winter and summer solstice and the days of the spring and autumn equinoxes for a period of 24 hours by applied the International Reference Ionosphere model IRI (2016). The output data for foF2 were verified by using the IRI-Ne- Quick option by specifying the time, date and Sunspot number parameters. Statistical analysis was caried out through the application of the Minitab (version 2018) in order to find the correlation between the critical frequency (foF2) of Ionospheric layer F2 and Sunspot number. It was concluded that the correlation is strong and positive, this indicate that critical frequency (foF2) increase with increasing Sunspots number (Ri) for solar cycle 24.

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A straightforward estimation of the maximum sunspot number for cycle 23

Annales Geophysicae ◽

10.1007/s00585-999-0639-7 ◽

1999 ◽

Vol 17 (5) ◽

pp. 639-641

Author(s):

B. Mendoza ◽

J. Ramírez

Keyword(s):

Magnetic Fields ◽

Key Words ◽

Sunspot Number ◽

Solar Minimum ◽

Solar Physics ◽

Annual Number ◽

Precursor Method ◽

Maximum Sunspot

Abstract. Using the annual number of geomagnetically quiet days (aa < 20 γ) for the year after the solar minimum, this precursor method predicts that the maximum sunspot number for cycle 23 will be 140 ± 32, indicating that cycle 23 will be similar to cycles 21 and 22.Key words. Solar physics · astrophysics and astronomy (magnetic fields; general)

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A method to predict amplitude and date of maximum sunspot number

Chinese Science Bulletin ◽

10.1007/bf03182904 ◽

2000 ◽

Vol 45 (14) ◽

pp. 1287-1290 ◽

Cited By ~ 5

Author(s):

Yanben Han

Keyword(s):

Sunspot Number ◽

Maximum Sunspot

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Coronal mass ejections and sunspot number over solar cycle 24

International Journal of Innovative Research and Growth ◽

10.26671/ijirg.2021.6.10.101 ◽

2021 ◽

Vol 10 (6) ◽

Author(s):

Preetam Singh Gour ◽

Shiva Anon ◽

Devangana Shyamlan Chaturvedi

Keyword(s):

Solar Cycle ◽

Sunspot Number ◽

Coronal Mass Ejections ◽

Solar Cycle 24 ◽

Cycle 24

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Reassessing the Predictions of Sunspot Cycle 24

Proceedings of the International Astronomical Union ◽

10.1017/s1743921318001205 ◽

2018 ◽

Vol 13 (S340) ◽

pp. 319-320

Author(s):

Nipa J. Bhatt ◽

Rajmal Jain

Keyword(s):

Sunspot Number ◽

Data Center ◽

Activity Index ◽

Sunspot Cycle ◽

Prediction Method ◽

Maximum Amplitude ◽

Annual Maximum ◽

Sunspot Minimum ◽

Cycle 24 ◽

Geomagnetic Activity Index

AbstractPredictions of sunspot cycle are important due to their space weather effects. Bhattet al.(2009) predicted sunspot cycle 24 (Maximum amplitude: 92.8±19.6; Timing:October 2012±4 months) using relative sunspot number (International Sunspot Number), and average geomagnetic activity indexaaconsidering 2008 as the year of sunspot minimum. Owing to the extended solar minimum till 2009, we re-examine our prediction model. Also, the newly calibrated international sunspot number reduces many discrepancies in the old dataset and is available from Solar Influences Data Center (SIDC) website. Considering 2009 as sunspot minimum year and newly calibrated international sunspot number, (i) The annual maximum amplitude of cycle 24 = 118.5±24.4 (observed = 113.3±0.1), (ii) A smoothed monthly mean sunspot number maximum in January 2014±4 months (observed in February 2014). Our prediction method appears to be a reliable indicator for the predictability of cycle 25.

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Difference between even- and odd-numbered cycles in the predictability of solar activity and prediction of the amplitude of cycle 25

Annales Geophysicae ◽

10.5194/angeo-32-1035-2014 ◽

2014 ◽

Vol 32 (8) ◽

pp. 1035-1042 ◽

Cited By ~ 6

Author(s):

A. Yoshida

Keyword(s):

Solar Activity ◽

Sunspot Number ◽

Strongly Correlated ◽

Current Cycle ◽

Cycle 24 ◽

Peak Value

Abstract. It was shown previously that the sunspot number (SSN) at a point 3 years before the minimum is well correlated with the maximum SSN of the succeeding cycle, and a better correlation is obtained when the maximum SSN is replaced by the average SSN over a cycle for which the average SSN is calculated by dividing cycles at a point 3 years before the minimum (Yoshida and Yamagishi, 2010; Yoshida and Sayre, 2012). Following these findings, we demonstrate in this paper that the correlation between the SSN 3 years before the minimum and the amplitude of the coming cycle differs significantly between even-numbered and odd-numbered cycles: the correlation is much better for even-numbered cycles. Further, it is shown that the amplitude of even-numbered cycles is strongly correlated with that of the succeeding odd-numbered cycles, while the correlation between amplitudes of odd-numbered cycles and those of succeeding even-numbered cycles is very poor. Using the excellent correlations, we estimate the maximum SSN of the current cycle 24 at 81.3 and predict the maximum SSN of cycle 25 to be 115.4 ± 11.9. It is of note, however, that a peak of the SSN has been observed in February 2012 and the peak value 66.9 is considerably smaller than the estimated maximum SSN of cycle 24. We conjecture that the second higher peak of the SSN may appear.

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Size of the coming solar cycle 24 based on Ohl's Precursor Method, final estimate

Annales Geophysicae ◽

10.5194/angeo-28-1463-2010 ◽

2010 ◽

Vol 28 (7) ◽

pp. 1463-1466 ◽

Cited By ~ 13

Author(s):

R. P. Kane

Keyword(s):

Solar Cycle ◽

Sunspot Cycle ◽

Preliminary Estimate ◽

Precursor Method ◽

Solar Cycle 24 ◽

False Signal ◽

Final Estimate ◽

Cycle 24 ◽

Maximum Sunspot ◽

Aa Index

Abstract. In Ohl's Precursor Method (Ohl, 1966, 1976), the geomagnetic activity during the declining phase of a sunspot cycle is shown to be well correlated with the size (maximum sunspot number Rz(max)) of the next cycle. For solar cycle 24, Kane (2007a) used aa(min)=15.5 (12-month running mean), which occurred during March–May of 2006 and made a preliminary estimate Rz(max)=124±26 (12-month running mean). However, in the next few months, the aa index first increased and then decreased to a new low value of 14.8 in July 2007. With this new low value, the prediction was Rz(max)=117±26 (12-month running mean). However, even this proved a false signal. Since then, the aa values have decreased considerably and the last 12-monthly value is 8.7, centered at May 2009. For solar cycle 24, using aa(min)=8.7, the latest prediction is, Rz(max)=58.0±25.0.

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