A few years ago, the best solar models predicted that Solar Cycle 24 would be larger than Solar Cycle 23. Here is a plot from NOAA’s Space Weather Prediction Center (SWPC) during those heady days, this one being from April 20th, 2007. Note the predicted ranges in red:
Now, compare that prediction in 2007, to this plot of actual values today:
Sunspot Number Progression
Note that the current values plotted above still fall far short of the updated predictions that were made to account for a much lower Solar Cycle 24.
Back then NOAA said:
May 8, 2009 — Solar Cycle 24 Prediction Update The Solar Cycle 24 Prediction Panel has reached a consensus decision on the prediction of the next solar cycle (Cycle 24). First, the panel has agreed that solar minimum occurred in December, 2008. This still qualifies as a prediction since the smoothed sunspot number is only valid through September, 2008. The panel has decided that the next solar cycle will be below average in intensity, with a maximum sunspot number of 90. Given the predicted date of solar minimum and the predicted maximum intensity, solar maximum is now expected to occur in May, 2013. Note, this is a consensus opinion, not a unanimous decision. A supermajority of the panel did agree to this prediction.
June 27, 2008 During the annual Space Weather Workshop held in Boulder, CO in May, 2008, the Solar Cycle 24 Prediction Panel released an update to the prediction for the next solar cycle. In short, the update is that the panel has not yet made any changes to the prediction issued in April, 2007. The panel expects solar minimum to occur in March, 2008. The panel expects the solar cycle to reach a peak sunspot number of 140 in October, 2011 or a peak of 90 in August, 2012.
April 25, 2008 The official NOAA, NASA, and ISES Solar Cycle 24 prediction was released by the Solar Cycle 24 Prediction Panel on April 25, 2007. The Prediction Panel included members from NOAA, NASA, ISES and other US and International representatives. Press Briefings and presentations at the SEC Space Weather Workshop, plus additional announcements and information from the Panel are linked below. The Panel expects to update this prediction annually.
The Panel considered all Predictions of Solar Cycle 24 they found in the literature or received directly from an author. The May 24, 2007 List shows the predictions considered.
So much for “consensus” based predictions. Not just a basic consensus mind you, but a supermajority, like, ummm 97% or something like that. They even wrote a paper about that consensus, which you can read here.
Our resident solar expert, Dr. Leif Svalgaard was in the 3% that said no.
But even in that super-majority, there wasn’t really a true consensus on the numbers for Cycle 24, as this graphic illustrates:
They wrote then, bold mine:
Cycle 24 Maximum Prediction
• Will peak at a sunspot number of 140(±20) in October, 2011 (F10.7 = 187 sfu) Or
• Will peak at a sunspot number of 90(±10) in August, 2012 (F10.7 = 141 sfu)
– The panel is split! – The next cycle will be neither extreme, nor average
Svalgaard presented these graphs in a presentation made in Lund, 20 September 2005:
Svalgaard also published a paper in GRL with this title:
Sunspot cycle 24: Smallest cycle in 100 years?
With the exception of Svalgaard, the panel of consensus scientists were all wrong, and Cycle 24 is turning out to be a complete forecast bust, and the the lowest in 100 years, and it was neither extreme, nor average.
So much for consensus based science!
NOAA’s Press Briefing document: Solar Cycle 24 Consensus Prediction
Svalgaard’s Cycle 24 Prediction Lund.pdf (Lund, 2005)
Svalgaard’s GRL 2005 paper Cycle 24 Smallest 100 years.pdf
Meanwhile, other indicators besides the sunspot number show cycle 24 remaining in a slump.
F10.7cm Radio Flux Progression
In all of the plots, the black line represents the monthly averaged data and the blue line represents a 13-month smoothed version of the monthly averaged data. For the Sunspot Number and F10.7cm, the forecast for the rest of the solar cycle is given by the red line.