An early prediction of the maximum amplitude of the solar cycle 25

Helal, Hamid R.; Galal, A. A.

doi:10.1016/j.jare.2012.10.002

Cited by 37 publications

(15 citation statements)

References 16 publications

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“…The values show that the predicted peak of SC 25 changes by about 11 sunspots for every 1‐nT change in the assumed precursor Ap index. Recently, Helal and Galal () forecasted the SC 25 using the precursor technique of spotless events and obtained maximum amplitude and time of rise to be 118.2 and 4.0 years, respectively. While their rise time is only about 9 months different from our value of4.75 years, simulations from our HR‐NN model indicate that the peak value of SSN will agree with their value of ~118 only if the precursor Ap index value gets as low as ~5.2 nT.…”

Section: Discussionmentioning

confidence: 99%

A Hybrid Regression‐Neural Network (HR‐NN) Method for Forecasting the Solar Activity

et al. 2018

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The Sun is the major driver of space weather events, and as a result, most applications requiring modeling/forecasting of space weather phenomena depend largely on the activities of Sun. Accurate modeling of solar activity parameters like the sunspot number (SSN) is therefore considered significant for the quantitative modeling of space weather phenomena. Sunspot number forecasts are applied in ionospheric models like the International Reference Ionosphere model and in several other projects requiring prediction of space weather phenomena. A method called Hybrid Regression‐Neural Network that combines regression analysis and neural network learning is used for forecasting the SSN. Considering the geomagnetic Ap index during the end of the previous cycle (known as the precursor Ap index) as a reliable measurement, we predict the end of solar cycle 24 to be in March 2020 (±7 months), with monthly SSN 5.4 (±5.5). Using an estimated value of precursor Ap index as 5.6 nT for solar cycle 25, we predict the maximum SSN to be 122.1 (±18.2) in January 2025 (±6 months) and the minimum to be 6.0 (±5.5) in April 2031 (±5 months). We found from the model that on changing the assumed value of precursor Ap index (5.6 nT) by ±1 nT, the predicted peak of solar cycle 25 changes by about 11 sunspots for every 1‐nT change in the assumed precursor Ap index.

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Section: Discussionmentioning

confidence: 99%

A Hybrid Regression‐Neural Network (HR‐NN) Method for Forecasting the Solar Activity

et al. 2018

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“…The Solar Cycle 25 prediction of Helal and Galal [] used the new calibration of R Z and found that the number of spotless days was a better predictor than with the old calibration [as discussed in Pesnell , ].…”

Section: Progress In Solar Cycle Data Setsmentioning

confidence: 99%

“…For example, DeJager and Duhau [] refined a previous geomagnetic precursor ( aa ) prediction for Solar Cycle 24 and laid the groundwork for Solar Cycle 25. Helal and Galal [] used a correlation between the number of spotless days and the upcoming solar maximum to update an earlier prediction to R 24 = 91.6 ± 11.3 in 2013.4 and estimated Solar Cycle 25 will have R 25 = 118.2, peaking 4.0 years after the upcoming solar minimum. Yoshida [] used correlations between R Z before minimum with the upcoming solar maximum, splitting the even/odd cycles to derive R 24 = 81.3 and R 25 = 115.4 ± 11.9.…”

Section: Anticipating the Next Solar Cyclementioning

confidence: 99%

Predictions of Solar Cycle 24: How are we doing?

Pesnell

2016

Space Weather

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Predictions of solar activity are an essential part of our Space Weather forecast capability.Users are requiring usable predictions of an upcoming solar cycle to be delivered several years before solar minimum. A set of predictions of the amplitude of Solar Cycle 24 accumulated in 2008 ranged from zero to unprecedented levels of solar activity. The predictions formed an almost normal distribution, centered on the average amplitude of all preceding solar cycles. The average of the current compilation of 105 predictions of the annual-average sunspot number is 106 ± 31, slightly lower than earlier compilations but still with a wide distribution. Solar Cycle 24 is on track to have a below-average amplitude, peaking at an annual sunspot number of about 80. Our need for solar activity predictions and our desire for those predictions to be made ever earlier in the preceding solar cycle will be discussed. Solar Cycle 24 has been a below-average sunspot cycle. There were peaks in the daily and monthly averaged sunspot number in the Northern Hemisphere in 2011 and in the Southern Hemisphere in 2014. With the rapid increase in solar data and capability of numerical models of the solar convection zone we are developing the ability to forecast the level of the next sunspot cycle. But predictions based only on the statistics of the sunspot number are not adequate for predicting the next solar maximum. I will describe how we did in predicting the amplitude of Solar Cycle 24 and describe how solar polar field predictions could be made more accurate in the future.

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“…At least 13 predictions of the amplitude of Solar Cycle 25 already exist. Some were from before 2016 and use R Z (Dumitrache, 2011;Helal & Galal, 2013;Javaraiah, 2015;Kakad, 2011;Lampropoulos et al, 2016;Li et al, 2015;Miao et al, 2015;Yoshida, 2014;Zachilas & Gkana, 2015). Others report their results with S N (Gkana & Zachilas, 2016;Pesnell & Schatten, 2018) or as fractions of previous activity (De Jager & Duhau, 2012;Shepherd et al, 2014).…”

Section: Introduction To Solar Cycle Predictionsmentioning

confidence: 99%

“…Others report their results with S N (Gkana & Zachilas, 2016;Pesnell & Schatten, 2018) or as fractions of previous activity (De Jager & Duhau, 2012;Shepherd et al, 2014). The Solar Cycle 25 prediction of Helal and Galal (2013) used R Z to derive a correlation between the number of spotless days and the rise time. But Pesnell (2012) showed that the number of spotless days in S N was a more accurate precursor.…”

Section: Introduction To Solar Cycle Predictionsmentioning

confidence: 99%

Effects of Version 2 of the International Sunspot Number on Naïve Predictions of Solar Cycle 25

Pesnell

2018

Space Weather

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The recalibration of the International Sunspot Number brings new challenges to predictions of Solar Cycle 25. One is that the list of extrema for the original series is no longer usable because the values of all maxima and minima are different for the new version of the sunspot number. Timings of extrema are less sensitive to the recalibration but are a natural result of the calculation. Predictions of Solar Cycle 25 published before 2016 must be converted to the new version of the sunspot number. Any prediction method that looks across the entire time span will have to be reconsidered because values in the nineteenth century were corrected by a larger factor than those in the twentieth century. We report a list of solar maxima and minima values and timings based on the recalibrated sunspot number. Naïve forecasts that depend only on the current values of the time series are common in economic studies. Several naïve predictions of Solar Cycle 25, the climatological average (180 ± 60), two versions of the inertial forecast, and two versions of the even‐odd forecast, are derived from that table. The climatological average forecast is the baseline for more accurate predictions and the initial forecast in assimilative models of the Sun. It also provides the error estimate for Monte Carlo techniques that anticipate the long‐term effects on the terrestrial environment. The other four predictions are shown to be statistically insignificant.

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An early prediction of the maximum amplitude of the solar cycle 25

Cited by 37 publications

References 16 publications

A Hybrid Regression‐Neural Network (HR‐NN) Method for Forecasting the Solar Activity

A Hybrid Regression‐Neural Network (HR‐NN) Method for Forecasting the Solar Activity

Predictions of Solar Cycle 24: How are we doing?

Effects of Version 2 of the International Sunspot Number on Naïve Predictions of Solar Cycle 25

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