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In reply to Cypher's: Solar Cycle 24 is going to be a Solar Minimum?
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There are conflicting predictions as to whether solar cycle 24 will be high or low. I believe there is agreement that cycle 25 will be very low based on the current solar magnetic field model. The following is a summary of this issue.
The NASA solar cycle prediction panel was split: Half of the panel predicted solar cycle 24 will be a high cycle and the other half predicted a low cycle. The NASA solar panel’s predictions are based on solar models that use recent (last 30 years) solar observations, not long term solar behaviour (last 15000 years), to make their predictions.
Based on the long term historical solar cycle record, there is a rump cycle before a Maunder like minimum. Based on analysis of the long term solar activity proxy data there was a prediction that cycle 23 should be a low cycle. It was not, however, there is now observational evidence of a step change in the solar cycle.
The following is more information concerning current solar observations, other researcher’s predictions, and past solar behaviour.
Observation:
This press release in May 2006 was issued to note an observed step change in the solar conveyor speed. The timing of this change coincides with the prediction of the solar inertial hypothesis. (There is a 180 year cycle in the solar barycentre motion. Those researchers who support the solar inertial hypothesis believe that specific solar barycentre motional changes, triggers a change in the solar cycle.)
http://science.nasa.gov/headlines/y2..._longrange.htm
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…"Normally, the (my comment, solar) conveyor belt moves about 1 meter per second—walking pace," says Hathaway. "That's how it has been since the late 19th century." In recent years, however, the belt has decelerated to 0.75 m/s in the north and 0.35 m/s in the south. "We've never seen speeds so low."…
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Based on the current theory for the solar magnetic field a slowing of the solar conveyor in 2006 should result in a very low cycle for cycle 25.
Proxy Data:
Based on an examination of proxy data that is used to determine solar activity levels, this paper predicts cycle 24 should be low. A solar cycle prediction based solely on an analysis of proxy data, is some what suspect, however, as there is no mechanism, to explain why there would be semi-periodic changes to the solar magnetic field. The solar inertial hypothesis might be the missing mechanism to explain what could be causing the solar magnetic field changes, in the proxy long term record.
http://adsabs.harvard.edu/abs/2004ApJ...605L..81B
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….We have examined the long-term trends in the solar variability that can be deduced from some indirect data and from optical records. We analyzed the radiocarbon measurements for the last 4500 years, based on dendrochronology… last 1700 years, based on auroral records, and the Hoyt-Schatten series of group sunspot numbers. Focusing on periodicities near one and two centuries, which most likely have a solar origin, we conclude that the present epoch is at the onset of an upcoming local minimum in the long-term solar variability. There are some clues that the next minimum will be less deep than the Maunder minimum, but ultimately the relative depth between these two minima will be indicative of the amplitude change of the quasi-two-century solar cycle….
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