As I mentioned a few days ago, there was a panel that NASA convened to look at solar cycle 23/24 predictions.
From this story on space.com where they talk about the opposing views solar scientists have for cycle 24 they offer some opinions. NOAA Space Environment Center scientist Douglas Biesecker, who chaired the panel, said in a statement:
[…] despite the panel’s division on the Sun cycle’s intensity, all members have a high confidence that the season will begin in March 2008
Well, obviously March 2008 isn’t happening:
Current sun: blank
So now there’s a new set of numerical predictive numbers issued by NASA solar physicist David Hathaway. You can see the March 2008 updated prediction page here:
There is a lot of discussion there on how the numbers are derived, but plainly absent from the discussion is the real meat of the issue. The goalposts for the start of Cycle 24 have now been moved to May 2008. In addition to the discussion of the “hows” on that page, he also produced a set of numerical data for the prediction curves which you can see here: http://solarscience.msfc.nasa.gov/images/ssn_predict.txt
I’ve plotted the data for you below.
Click for a larger image
Notice how cycle 23 gets longer and longer, with a sharp upturn for cycle 24 starting in late 2008 and early 2009. Hathaway still believes cycle 24 will be slightly more in amplitude than cycle 23, while others think it will be lower.
I’m no solar physicist, but based on what I’ve seen, I’m betting the goalposts will be moved again in May, pointing to a start in August or September 2008. This would be more in line with the latest numbers predicted by the Space Environment Center (SEC):
We’ll see what happens. I’m still very much concerned about the apparent step change in 2005 to a lower plateau of the Geomagnetic Average Planetary (Ap) index. Which is something that does not appear in the previous cycle:
click for a larger image
What is most interesting about the Geomagnetic Average Planetary Index graph above is what happened around October 2005. Notice the sharp drop in the magnetic index and the continuance at low levels, almost as if something “switched off”.
UPDATE – Joe D’Aleo of ICECAP writes in with this:
This site http://users.telenet.be/j.janssens/SC24.html catalogs the many forecasts of the next cycle with links where available. The majority of these forecasts (23 of the 33) forecast a quieter cycle 24 than 23.
The Clilverd forecast http://users.telenet.be/j.janssens/SC24Clilverd.pdf is the lowest (peak SSN 42).
Dikpati http://www.ucar.edu/news/releases/2004/sunspot.shtml the highest (peak SSN 169). Hathaway of NASA was second highest (peak SSN 160) though he projected that cycle 25 could be quietest in centuries due to dramatic slowing of the conveyor belt of hot plasma http://science.nasa.gov/headlines/y2006/10may_longrange.htm
If we go to May or later before the solar min is reached, cycle 23 will be the longest cycle since the late 1800s.