By David Archibald
Joe D’Aleo asked for my comments on NASA’s James Hathaway’s latest solar prediction, available here: http://solarscience.msfc.nasa.gov/predict.shtml
When I read May 2013 for solar cycle maximum, I thought “That is my prediction”.
But then at the bottom of the page, they provide text files of their sunspot number prediction and F10.7 flux prediction. So I downloaded the data and plotted it up, and I found that NASA is providing a number of predictions re the month of solar cycle maximum:
The F10.7 flux data plotted is less the magnetic floor of 64.
Firstly, their actual peak by the numbers is February and March 2013. Secondly, their forecast peak of F10.7 flux is September 2013. Sunspot number and F10.7 flux should be in lockstep.
So it total, NASA have provided three estimates of the timing of Solar Cycle 24 maximum in the one release.
What I find more interesting is what their F10.7 flux profile implies if it is correct. It suggests that Solar Cycle 24 will be a very long cycle with the 24/25 minimum in 2021 or even 2022, making it 13 to 14 years long – possibly up to 18 months longer than Solar Cycle 23.
With the solar cycle length/temperature relationship of 0.7°C for the US – Canadian border, the NASA profile implies a further cooling of perhaps 1.0°C in Solar Cycle 25.
In terms of neutron count, things aren’t all that different from previous cycles:
This figure shows the first four years of average Oulu monthly neutron count for the last five solar cycles, aligned on the month of solar minimum. While Solar Cycle 24 is currently providing 17% more neutrons than the super-hot Solar Cycle 22 at the same stage, it isn’t all that different from the other three cycles to date.
By comparison, the Ap Index has just recovered to the levels of previous solar minima, three years into Solar Cycle 24: