The December data from NOAA’s Space Weather Prediction Center is in, and it looks more and more like the peak of solar cycle 24 has been reached, and that we are now past it. Even with documented problems like “sunspot count inflation” the sunspot count for December is quite low:
Note the large difference between the prediction line in red, and the counts. There are other indications that our sun remains in a slump.
The 10.7cm solar radio flux seems to have peaked also.
And, the Ap solar geomagnetic index has dropped to its observed second lowest value again (for recent years), which last happened in November 2011:
Dr. David Hathaway updated his forecast recently. Here is the plot:
He thinks it will be the fall of 2013 though before the peak is reached
The current prediction for Sunspot Cycle 24 gives a smoothed sunspot number maximum of about 69 in the Fall of 2013. The smoothed sunspot number has already reached 67 (in February 2012)due to the strong peak in late 2011 so the official maximum will be at least this high and this late. We are currently over four years into Cycle 24. The current predicted and observed size makes this the smallest sunspot cycle since Cycle 14 which had a maximum of 64.2 in February of 1906.
The prediction method has been slightly revised. The previous method found a fit for both the amplitude and the starting time of the cycle along with a weighted estimate of the amplitude from precursor predictions (polar fields and geomagnetic activity near cycle minimum). Recent work [see Hathaway Solar Physics; 273, 221 (2011)] indicates that the equatorward drift of the sunspot latitudes as seen in the Butterfly Diagram follows a standard path for all cycles provided the dates are taken relative to a starting time determined by fitting the full cycle. Using data for the current sunspot cycle indicates a starting date of May of 2008. Fixing this date and then finding the cycle amplitude that best fits the sunspot number data yields the current (revised) prediction.
Perhaps, the sun right now seems to be having a spot resurgence:
In other news, Dr. Svalgaard’s plot:
Solar Polar Fields – Mt. Wilson and Wilcox Combined -1966 to Present
…looks like it is getting ready to flip, suggesting the peak of Cycle 24 is imminent if not already past.
His predictions for cycle 24 are looking better and better.