Landscheidt, Part 6
Posted by The Diatribe Guy on June 20, 2008
Please go here for the previous Landscheidt articles, if you’re just catching up now. This will greatly aid in the context of what I am writing about.
Moving on to the next statement in the Landscheidt paper, Swinging Sun, 79-Year Cycle, and Climatic Change, he states: According to Gleissberg (1975) the discovery of corresponding long-term recurrence tendencies in sunspot frequency would be of considerable importance, for it would make possible accurate long-range forecasts of low-frequency variations.
The 1975 paper by W. Gleissberg is the German-penned “Gibt es in der Sonnenfleckenhaufigkeit eine 179-jahrige Wieder-holungstendez?” It’s attribution is as follows: “Verdff. Astron. Inst. Univ. Frankfurt, 57: 2, 11.” Not only couldn’t I track down an English version of this paper with my meager resources, but I couldn’t find the original German version, either. Not that it would have done me much good, other than to be amused at things like “Sonnenfleckenhaufigkeit.” Those Germans have quite a way of putting things…
It is probably helpful, though, to reference the importance of the Gleissberg cycle. This is either about 78 years or 88 years, depending on whether talking about 7 solar cycles or eight. However, as referenced here, it is the 78 year cycle. Gleissberg, long before the referenced paper here, detected long-term solar cycles using low-pass filtering techniques on both height and length of solar cycles. Basically, the results are that: seven solar cycles usually occupy between 77 and 79 years, but always more than 72 years and always less than 83 years.
Landscheidt further seems to allude to the fact that Gleissberg seemed to believe that not only do the lengths of the cycles add up to these values, but there may be predictive value based on where in such a cycle we are and its implications on amplitude of the solar cycle.
The Maunder Minimum and the Spoerer Minimum coincide with troughs in the 80-yr cycle of sunspot activity (80 YC) which according to Gleissberg (1975) and Hartmann (1972) occurred about 1500 and 1670.
Landschedit adopts the convention here of using 80 years as the Gleissberg cycle value (80 YC). We all like round numbers. Even actuaries. Here is the credited article by Hartmann: “HARTMANN, R. (1972): Vorlдufige Epochen der Maxiraa und Minima des 80-jдhrigen Sonnenfleckenzyklus. Verцff. Astron. Inst. Univ. Frankfurt, 50: 118.” Again, I didn’t delve into the German. But in any case, this is relatively straightforward: there is a “trough” point in the cycle, and this point coincided with the Grand Minimums we previously discussed. Clearly, though, not all trough points are created equal, because these extended minimums do not recur every 80 years – thank goodness. So, while this cycle is still a valuable weapon in the arsenal of our attack on… OK, this metaphor isn’t working. But you understand the point. Or maybe not. Let’s move on.
Moreover, the two grand minima in question are separated by an interval which is near the 179-yr period of variation in the sun’s oscillatory motion about the center of mass of the solar system (Jose, 1965).
Ah, this is more like it. We now see that whole oscillatory motion and the center of mass of the solar system of which I have become so helplessly enamored. I know this makes me sound like a complete loser, but apparently if you are reading Part 6 of this series, you’re right there with me. Admitting it is the first step. Back to topic, though, it is an interesting look at the separation of the two Grand Minima (Spoerer and Maunder Minimums) and this “coincidental” separation of 179 years. The referenced article here is: “JOSE, P.D. (1965): Sun’s motion and sunspots. Astron. J., 70: 193-200.”
I have located a copy of this. I am going to spend some time reviewing it, and will summarize the salient points on my next post.