Figure 4 in paper
Secular variation of hemispheric phase differences in the solar cycle
N.V. Zolotova, D.I. Ponyavin, R. Arlt2, and I. Tuominen
Published online 2010 Oct 1
Abstract
We investigate the phase difference of the sunspot cycles in the two hemispheres and compare it with the latitudinal sunspot distribution. If the north-south phase difference exhibits a long-term tendency, it should not be regarded as a stochastic phenomenon. We use datasets of historical sunspot records and drawings made by Staudacher, Hamilton, Gimingham, Carrington, Spörer, and Greenwich observers, as well as the sunspot activity during the Maunder minimum reconstructed by Ribes and Nesme-Ribes. We employ cross-recurrence plots to analyse north-south phase differences. We show that during the last 300 years, the persistence of phase-leading in one of the hemispheres exhibits a secular variation. Changes from one hemisphere to the other leading in phase were registered near 1928 and 1968 as well as two historical ones near 1783 and 1875. A long-term anticorrelation between the hemispheric phase differences in the sunspot cycles and the latitudinal distribution of sunspots was traced since 1750.
Tallbloke's Talkshop 
Thanks for this Tim, I’m going to start reading it tomorrow. Then I’ll comment.
Click to access aa8672-07.pdf
Correction to 1:59:
http://www.aanda.org/index.php?option=com_article&access=standard&Itemid=129&url=/articles/aa/abs/2007/45/aa8672-07/aa8672-07.html
Most of the solar research is below the public radar although I suspect not a lot new turns up.
You’ve found a paper with a similar focus, the conclusion though seems to be found nothing much, need more work. Yep.
Although not in the primary content there is a serious mistake which made it past review. Subharmonics do not exist in the real world, are a maths abstract thing, a common misconception.
Given the authors age/experience I suspect the paper was getting the feet wet.
For example, no solar interest (not meant to be derogatory)
http://www.abdn.ac.uk/engineering/people/details.php?id=m.thiel
http://www.pik-potsdam.de/members/redonner/dr.-reik-donner-publications
This is a shame because it blinds people to a very interesting and rich vein which is kind of picked up by the few who deal in the musical connection. This also brings in Fibonacci, golden ratio and lots more. (quick mental count, I own 6 woodwind, two made of metal)
I made a fibonacci connection today with the Jupiter distance thing.
Tim, where do you see reference to subharmonics?
“While studying the long-term variability of this indicator, we have found that there are no statistically significant periodicities of about 22 years (Swinson et al. 1986) or 44 years
(Knaack et al. 2004; Ballester et al. 2005), which correspond to the magnetic cycle of the Sun and its second harmonics.” — pdf page3, col 2, 3rd para
Magnetic cycle is 22 years. Second harmonic is 11 years, are periods.
Maybe English was the editor’s second language. Anyway, the authors draw attention to some beautiful methodology. One thing they didn’t point out: The absolute magnitude of asymmetry is directly proportional to activity.
“The absolute magnitude of asymmetry is directly proportional to activity.”
That’s something I noticed when I did my work on asymmetry, though it seems more generally true than an absolute rule:
Clarification: Absolute as in absolute value (i.e. the mathematical concept).
[One finds very high correlations, not absolutely perfect ones (the other sense of ‘absolute’).] Investigators should explore the “ladder of powers” (covered in Stat 101 – includes square roots & logs) since the distribution is skewed. [Note: An offset is needed for logs to avoid log(0).]