Predictions of Solar Cycle 24: How are we doing?

Abstract

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.

A history of solar activity over millennia

“…Forecasting solar activity has been a subject of intense study for many years (e.g., Yule 1927;Newton 1928;Gleissberg 1948;Vitinsky 1965) and has greatly intensified recently with a hundred of journal articles being published to predict the solar cycle No. 24 maximum (see, e.g., reviews by Pesnell 2012Pesnell , 2016, following the boost of space-technology development and increasing debates on solar-terrestrial relations. In fact, the situation has not been improved since the previous cycle, No.…”

Variational Estimation of the Large-scale Time-dependent Meridional Circulation in the Sun: Proofs of Concept with a Solar Mean Field Dynamo Model

“…Such numerical models require the definition of adequate initial conditions which are obtained through the technique of data assimilation (Petrovay 2010;Dikpati & Gilman 2006;Pesnell 2016). Data assimilation is an emerging technique in solar cycle and activity prediction, which is a way to incorporate observations in numerical models (Brun 2007).…”

Development of Adaptive Moving Two–sided Exponential Smoothing Method for Restoring and Forecasting of Time Series

“…It is shown in the Fig. 1 that on the time intervals [5,10] and [15,20] there is a distortion of the process for a model constructed by the method of 13-month moving average: there is rotation of the fluctuations of the Wolf numbers. It is shown in the Fig.…”

“…It is shown in the Fig. 2 that on the time interval [10,25] for the model, which is constructed using 13-month moving average method, there is significant distortion of the process: fluctuations are zeroed on the time intervals [10,15] and [20,25], there is rotation of the fluctuations of the index F10.7 on the time interval [15,20]. At the same time, adaptive moving two-sided exponential smoothing does not distort the fluctuations during the restoration of the true regularities of the index F10.7.…”

“…It is shown in the work [15] that proposed model can be used both for describing of regularities and for forecasting of Wolf numbers. The state of the research regarding forecasting of solar cycles nowadays is shown and approach for increasing the accuracy of forecast is proposed in the work [20].…”