Guest post by David Archibald
In a presentation dated 22nd September, 2009, Dr Svalgaard produced a graphic which can be interpreted to predict the timing of the Solar Cycle 24 maximum.
That presentation is available here: http://www.leif.org/research/Predicting%20the%20Solar%20Cycle.ppt
That graphic is reproduced with my annotation:
Dr Svalgaard annotated Altrock’s orgininal figure with the red and aqua arrows. What is significant is that the Solar Cycle 24 arrow is 15 years after the Solar Cycle 23 arrow. With the maximum of Solar Cycle 23 in March 2000, that line suggests that the Solar Cycle 24 maximum will be in 2015.
With the timing of the next maximum established, we can compare the progression of the current minimum with the minimum that saw the beginning of the Maunder Minimum. Makarov and Tlatov in 2000 included a figure from Kocharov 1995. That figure follows, with my annotation:
Tree rings from the Urals have more uses than just making hockey sticks. Due to the paucity of sunspots in the Maunder Minimum (1645 – 1710), C14 data provides the evidence for the presence of solar cycles and their length. According to Makarov and Tlatov, solar cycles averaged 20 years long in the Maunder. In Figure 2 above, solar minima are associated with higher C14 content and are on the top side of the graphic. I have marked the solar minima with vertical blue lines. The blue figures along the x axis are the length of the solar cycles from minimum to minimum in years.
To compare the start of the Maunder Minimum to our current day minimum, I have marked where the maximum of Solar Cycle 24 would be in 2015 as 15 years after the peak of the preceding cycle. There is also a parallel in the way that the C14 count (reflecting the neutron flux and in turn the GCR flux) is climbing above the peaks of previous minima, as it is today with the Oulu neutron count. Neutron count tends to peak a year after solar maximum, so a neutron peak in 2010 is consistent with solar minimum in 2009.
From Figure 2, it can be expected that in a repeat of the Maunder Minimum, the neutron flux will remain well above the levels reached in the minima of the second half of the 20th century.
The Maunder Minimum was not completely devoid of sunspots, as shown by the following graphic using data from SIDC:
Lastly, the Heliospheric Current Sheet has flattened, one of the conditions for the solar minimum:
A ramp up in Solar Cycle 24 activity might not be expected though until the downtrend line in tilt angle from the peak in 2000 is broken, and that might be a year away.
Activity and timing of the current minimum, as well as the timing of the Solar Cycle 24 maximum in 2015, is paralleling the start of the Maunder Minimum. There is no data to date which diverges from the pattern of the start of the Maunder Minimum.