Prediction of Future Solar Cycles 24-38

To the lay man, the sun's energy output appears to be constant. However, invention of the telescope and beginning of the space era lead to the conclusion that sun's energy output is not constant. The sunspots-magnetically active regions on the sun's surface with dark and cool structures compared to the ambient medium-are one of the interesting aspects of the solar activity that immensely contribute to the variation of the sun's energy output. Variation of the occurrence of number of sunspots over the surface of the sun with an average periodicity of ~ 11 years is termed as sunspot or solar cycle.

The sunspots are also associated with the triggering of transient events such as flares (Hiremath, K. M and Suryanarayana., Astronomy and Astrophysics (Letters), 411, L497, 2003) and coronal mass ejections. Occurrence of such transient events of the solar activity that are directed towards the earth create
havoc in the earth's atmosphere by disrupting the global communication, reducing life time of the low-earth-orbit satellites and, cause electric power outages.
Owing to sun's immense influence of the space weather effects on the earth's environment and climate in general and, Indian Monsoon rainfall in particular (Hiremath and Mandi, New Astronomy, 9, 651, 2004 and references there in; Hiremath, K. M., ILWS workshop, 2006; Hiremath, K. M., Journal of Astrophysics and Astronomy, 27, 367, 2006), it is necessary to predict and know in advance different physical parameters such as amplitude and period of the future
solar cycles.

Recently we (Hiremath, K. M., Astronomy and Astrophysics, 452, 591, 2006) modeled the solar activity cycle as a forced and damped harmonic oscillator.
From the 22 cycles (1755-1996) sunspot data, the physical parameters (amplitudes, frequencies, phases and decay factors) of such a harmonic oscillator are determined. The constancy of the amplitudes and the frequencies of the sinusoidal part and a very small decay factor from the transient part suggests that
the solar activity cycle mainly consists of persistent oscillatory part that might be compatible with long-period (~ 22 ) Alfven oscillations. In the present study, with an autoregressive model and by using the physical parameters of previous 22 cycles (1755-1996), we predict the amplitudes and periods of present cycle (23) (Fig. 1) and future fifteen (Fig. 2) solar cycles.

Following are the salient features of the predictions. (1) The predicted period and amplitude of the present cycle 23 are almost similar to the period and amplitude of the observed cycle. (2) It is expected that onset of next sunspot activity cycle 24 might starts during the period 2008.57 ± 0.17 (i.e., around May-Sept 2008).
(3) The period and amplitude of the cycle 24 are 9.34 years and 110 (± 11). (4) The period and amplitude of the cycle 25 are 12.49 years and 110 (± 11).
(4) During the cycles 26 (2030-2042 AD), 27 (2042-2054 AD), 34 (2118-2127 AD), 37 (2152-2163 AD) and 38 (2163-2176 AD), the sun might experience a very high sunspot activity. (5) The sun might also experience a very low ( around 60) sunspot activity during cycle 31 (2089-2100 AD) and, (6) length of the solar cycles vary from 8.65 yrs for the cycle 33 to maximum of 13.07 yrs for the cycle 35.

Although the sun can not behave according to our expectations, if predictions of this study on the amplitudes and periods of the coming solar cycles come true, one has to consider seriously the alternative physical model on the origin of the solar cycle and activity phenomena as proposed by this author.

The details of this study will appear in the Astrophysics and Space Science. The preprint can either be obtained from the author (hiremath@iiap.res.in) or from the institute's open access repository (http://prints.iiap.res.in/).