Guest post by David Archibald
Dr Svalgaard has an interesting annotation on his chart of solar parameters – “Welcome to solar max”:
Graphic source: http://www.leif.org/research/TSI-SORCE-2008-now.png
Could it be? It seems that Solar Cycle 24 had only just begun, with solar minimum only two and a half years ago in December 2008.
The first place to confirm that is the solar polar magnetic field strength, with data from the Wilcox Solar Observatory:
The magnetic poles of the Sun reverse at solar maximum. The northern field has reversed. There are only three prior reversals in the instrument record. Another parameter that would confirm solar maximum is the heliospheric current sheet tilt angle, also from the WSO site.
The heliospheric current sheet tilt angle has taken a couple of years to reach solar maximum from its current level.
If the Sun is anywhere near solar maximum, the significance of that is that it would be the first time in the record that a short cycle was also a weak cycle, though Usoskin et al in 2009 proposed a short, asymmetric cycle in the late 18th century at the beginning of the Dalton Minimum: http://climate.arm.ac.uk/publications/arlt2.pdf
Interestingly, Ed Fix (paper in press) generated a solar model (based on forces that dare not speak their name) which predicts two consecutive, weak solar cycles, each eight years long:
The green line is the solar cycle record with alternate cycles reversed. The red line is the model output. Solar Cycles 19 to 23 are annotated.
This model has the next solar maximum in 2013 and minimum only four years later in 2017. This outcome is possible based on the Sun’s behaviour to date.