NOAA’s Space Weather Prediction Center (SWPC) produced their monthly solar cycle progression update yesterday. The news is not encouraging. We’ve had a drop in solar activity again in December, The sunspot count is lower, but the really worrisome thing is the Ap geomagnetic index. The solar dynamo has now dropped to magnetic activity levels last seen in late 2009. Readers may recall this post from December 23rd: Solar Geomagnetic Ap Index Hits Zero which was a bit unusual this far into cycle 24.
The Ap value of 3 was last seen in late 2009 and early 2010, which bracketed the lowest value seen in 10 years (on the SWPC graph) of Ap=2 in December 2009. It was also the lowest value in the record then. SWPC has since revised their data upwards from 1 to 2 for December 2009. Here’s what it looked like then:
And here is the story at that time:
The 10.7 centimeter radio flux is a bit more encouraging, but still rather anemic compared to where to where it should have been in the solar cycle.
Here’s the data: http://www.swpc.noaa.gov/ftpdir/weekly/RecentIndices.txt
The last major update to NOAA’s prediction came in May 2009 when they wrote:
May 8, 2009 — 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.
It seems to be time again for an update, since it seems likely that the “consensus prediction” has failed.
The Livingston and Penn data (from Dr. Leif Svalgaard) continues unabated and on track for sunspots to become invisible when the umbral magnetic field reaches ~1500 gauss.
But the rest of the world is now just getting around to realizing the significance of the work Livingston and Penn are doing related to sunspots. Science ran with a significant story: Say goodbye to sunspots
Here’s a prominent excerpt:
The last solar minimum should have ended last year, but something peculiar has been happening. Although solar minimums normally last about 16 months, the current one has stretched over 26 months—the longest in a century. One reason, according to a paper submitted to the International Astronomical Union Symposium No. 273, an online colloquium, is that the magnetic field strength of sunspots appears to be waning.
Scientists studying sunspots for the past 2 decades have concluded that the magnetic field that triggers their formation has been steadily declining. If the current trend continues, by 2016 the sun’s face may become spotless and remain that way for decades—a phenomenon that in the 17th century coincided with a prolonged period of cooling on Earth.
We live in interesting times.