This Paper by I. R. G. Wilson, B. D. Carter, and I. A. Waite is now available free onliine. http://www.publish.csiro.au/?act=view_file&file_id=AS06018.pdf
Abstract:We present evidence to show that changes in the Sun’s equatorial
rotation rate are synchronized with changes in its orbital motion about the
barycentre of the Solar System.We propose that this synchronization is
indicative of a spin–orbit coupling mechanism operating between the
Jovian planets and the Sun. However, we are unable to suggest a plausible
underlying physical cause for the coupling. Some researchers have proposed
that it is the period of the meridional flow in the convective zone of the Sun
that controls both the duration and strength of the Solar cycle.We postulate
that the overall period of the meridional flow is set by the level of disruption
to the flow that is caused by changes in Sun’s equatorial rotation speed.
Based on our claim that changes in the Sun’s equatorial rotation rate
are synchronized with changes in the Sun’s orbital motion about the
barycentre, we propose that the mean period for the Sun’s meridional flow
is set by a Synodic resonance between the flow period (?22.3 yr), the overall
178.7-yr repetition period for the solar orbital motion, and the
19.86-yr synodic period of Jupiter and Saturn.
Some very interesting sections of this paper discuss changes in angular momentum and solar equatorial rotation change. I would like to see more work in this area, as there is scant amount of detail available on my searching. There must be someone working on comparing current solar differential rotation with other periods?
In another section the paper acknowledges the work done by Fairbridge & Shirley 1987 in using all of the Jovian planets to calculate angular momentum but unfortunately dont include Neptune & Uranus any further. I believe Fairbridge & Shirley were SO close in 1987 but failed to see the absolute importance of Neptune & Uranus…they had a graph like Carl’s but didnt cross check it against the planetary line ups. Incredible that they went so far but didnt go the extra step. Its now some 22 years later.
But the most important discovery by Wilson et al in this paper in my view, is their “phase locking” theory. Grand Minima type events (SSN less than 80) have happened in the past when the conjunction of Jupiter & Saturn happens before that cycle’s maximum, implying a mechanism of catch up, keeping the Jupiter/Saturn sysygies in line with solar cycles. I refer to this in other articles as “Wilson’s Law”. If SC24 peaks after March 2011 it will fit that criteria as well as SC25 if it peaks after Nov 2020. This phenomenon has always happened at or just after the “camel hump” disturbance on Carl’s graph, and begs the question: Does this phenomenon happen as a result of the major disturbance to the angular momentum or is that just coincidence? To test this I might plot all the sysygies and cycle max’s on Carl’s Graph.
UPDATE: below is a graph showing J+S sysygies with sunspot peaks, Note: pre 1700 solar cycle maxima is derived geomagnetic aa proxy figures, click on the graph for a larger image.
Ian’s work has answered some of my questions and explains why 1830 didnt invoke further Grand Minimum action, also why 1880 (SC12) was low during higher angular momentum, Its obvious if the aa records are correct that we have a higher frequency of early J+S sysygies with the higher angular momentum caused by N+U.
Black dots are J+S together, Blue dots J+S opposed, and Red dots are solar cycle maxima…..reduced solar activity occurs if we get a black or blue dot in between cycle minimum and before cycle maximum