By Paul L. Vaughan, M.Sc.
The amplitude of Earth’s zonal winds is modulated by the solar cycle. Here’s a concise visual update based on the latest data:
LOD’ = rate of change of length of day
Data
ftp://ftp.iers.org/products/eop/long-term/c04_08/iau2000/eopc04_08_IAU2000.62-now ftp://ftp.ngdc.noaa.gov/STP/SOLAR_DATA/COSMIC_RAYS/STATION_DATA/Monthly_data/moscow.tab
I once stumbled upon a publication by the FAO on LOD and Temperature, but I have never been able to fully digest it, so to say. It’s this one: http://www.fao.org/docrep/005/y2787e/y2787e00.htm#Contents
The most intreging figure in it, in chapter 2, is a comparison between LOD and ΔT: http://www.fao.org/docrep/005/y2787e/y2787e03b.htm#FiguraB
Does any of you know this study or does any of you want to take a look at it and give a response, whether it is related to this post on LOD?
I love these Solar posts. Leif is a star I haven’t seen him caught out yet!
Let’s raise our glasses to a true scientist: Leif Svalgaard.
Leif
I was hoping a 183 window would show the pattern we already see in the 91 window more clearly. There is a solar cycle pattern in your 91 window. Compare 1985 to 1992 for instance. The 0.5 cycle does not go that deep at solar max.
Paul Vaughan says:
December 26, 2011 at 2:30 pm
“I’m clarifying your obscure verbiage. And if you use a fixed window size [extent] also assume a clean cycle.”
Do the calculations for a variety of extents and you’ll learn something about FOCUS. The way my software works, I have dial, so I can tune manually.
Tune manually to what you wish for.
As I said, If there were a strong signal simple FFT [or even just eyeballing] would pick it up. Gross showed you what the amplitude of the semiannual variation looks like. See if you can match his. Think about what it means that only the semiannual wave is ever so slightly [in your analysis] influenced by the solar cycle.
Paul Vaughan says:
December 26, 2011 at 2:12 pm
“the 0.1K temperature variation caused by the solar cycle”
And how exactly is that distributed spatially over the globe in your abstraction?
Just like the other 99.9% of the photons from the Sun.
Leif Svalgaard says:
December 26, 2011 at 10:49 am
Juraj V. says:
December 26, 2011 at 10:22 am
AFAIK, LOD is well correlated with Pacific trade winds, which dictate the ENSO conditions, which.. the rest is history.
Indeed it is and Gross finds precisely that. Furthermore he shows that the dedacal signal in LOD is caused primarily by core-mantle boundary processes.
But what causes the core-mantle boundary processes? The correlation I found with the motion of the other solar system planetary masses suggests that there is a connection between them and the stirring of the Earth’s internal porridge. And we’ve also found correlations between those planetary motions and the solar cycles. I suggest this is why Paul has found a correlation between LOD’ and the solar cycle.
It’s a good puzzle.
Jimmy Haigh (December 26, 2011 at 3:07 pm)
“I love these Solar posts. Leif is a star I haven’t seen him caught out yet!”
We’ll see if he reproduces the calculations.
There are several different ways to isolate the semi-annual wave and the results are robust across them. I did the update using a different method from the original post [ http://wattsupwiththat.com/2010/12/23/confirmation-of-solar-forcing-of-the-semi-annual-variation-of-length-of-day/ ]. Same results. And the same results show up for a wide band around ~11 years (with the best focus in the middle). The results are stable. And there’s nothing wrong with the methods. They find widespread application, but they’re new enough (only decades old) that they’re not yet core in curricula. Everyone here could use them. There just isn’t a good introductory webpage yet that overviews them simply. I built online stats education modules for years. It would take a LOT of careful work to do a really good job.
Season’s Best.
tallbloke says:
December 26, 2011 at 4:07 pm
But what causes the core-mantle boundary processes? The correlation I found with the motion of the other solar system planetary masses suggests that there is a connection between them and the stirring of the Earth’s internal porridge.
It seemed to me [last time I looked at this] that such correlations brake down if we go back in time, e.g. http://www.leif.org/research/FFT%20of%20LOD.png and http://www.leif.org/research/LOD-Excess.png . The data is good enough for this.
lgl says:
December 26, 2011 at 3:54 pm
I was hoping a 183 window would show the pattern we already see in the 91 window more clearly. There is a solar cycle pattern in your 91 window. Compare 1985 to 1992 for instance. The 0.5 cycle does not go that deep at solar max.
According to Paul, there is a solar cycle in the 182-day period. Such cycle would be suppressed in a 182-day smooth. I can’t see any solar cycle in the 91-day window. Comparing this year with that year is not good enough to show cycles.
If there were a strong signal simple FFT [or even just eyeballing] would pick it up.
And it is very easy to eyeball http://virakkraft.com/LOD-Solar.png
Leif, it’s temperature GRADIENTS that drive the thermal wind. The data crush the silly notion of uniformity (e.g. polar night vs. polar day vs. equator – & the atmosphere doesn’t sit still – Earth’s a natural spatiotemporal filter). You’re going to have to drop that element of your narrative in order to continue being taken seriously on this particular point by sensible people. And again, Gross was looking at different statistics. You need to reproduce the graph. It’s the only way you’ll gain understanding. I encourage others to do the calculations too.
tallbloke says:
December 26, 2011 at 4:07 pm
And we’ve also found correlations between those planetary motions and the solar cycles. I suggest this is why Paul has found a correlation between LOD’ and the solar cycle.
The decadal-type variations Gross is talking about are not [t]ied to the solar cycle. See Figure 1 of
http://ebooks.gfz-potsdam.de/pubman/item/escidoc:8469:2/component/escidoc:8468/9810.pdf
The rest of that paper is illuminating too. Paul, too, would benefit from careful study of it. Especially Figure 7.
Tallbloke said, “It’s a good puzzle.”
Indeed! TSI variation on its own is nowhere near enough and geomagnetic change appears to be a stretch. LOD may be connected to core fluctuations which may be internal or in some way connected to orbital cycles. The shift in the tropical belt to me indicates that geomagnetic fluctuations may have some impact on cloud formation and distribution. The ratio of atmospheric absorption to surface absorption can easily double the impact of TSI changes if the duration is long enough allow OHC to reduce during a solar minimum.
There are a lot of small impacts with varying time constants. The over estimation of 2XCO2 impact is muddying the likelihood that sensitivity is non-linear and regional. What this job needs is a new project manager!
A solar signal can be mathematically calculated. This is well known and is cyclical. Trouble is, the noise of long and short term intrinsic drivers bury it. Any other solar affect would be smaller than that for verifiable reasons. The debate must close, not because of proposed theories but because a.gnat’s ass just doesn’t matter to feet on the ground trends in anomalous temps.
Leif Svalgaard (December 26, 2011 at 4:03 pm)
“Tune manually to what you wish for.”
You’re not reading what I wrote. There’s a WIDE band centered around ~11 years that points at ~11 years. (That means you can be off by quite a bit and STILL hit the target …BECAUSE THAT’S WHERE THE RESONANCE IS.) If you would do the calculations you would be empowered to OBSERVE this instead of falsely speculating and falsely ascribing imaginary motives that do not exist.
–
Leif Svalgaard (December 26, 2011 at 4:03 pm)
“As I said, If there were a strong signal simple FFT [or even just eyeballing] would pick it up.”
And once again: You’re wrong if you’re referring to plain FFT. Some windowed versions could do the job. Remember that IT’S A PROPERTY OF THE WINDOW, so if you don’t window, you don’t see it.
Instead of shooting the breeze, take 10min to do the calculations. You have all the info you need.
The claim here is that there is a correlation between length of day (or rate of change) and some index of solar magnetic activity. Do we need to go to periods of a full solar cycle to demonstrate this? Why not look for LOD effects in the aftermath of intense geomagnetic storms? I remember a claim that the intense events of early August 1972 changed the LOD for a time.
Scarface says:
December 26, 2011 at 2:36 pm
The most intreging figure in it, in chapter 2, is a comparison between LOD and ΔT
As the atmosphere heats up it expands and like a spinning ice skater extending her arms the rotation slows down…
Leif Svalgaard says:
December 26, 2011 at 7:57 am
..tallbloke says:
December 26, 2011 at 12:35 am
Leif: Isn’t the Neutron count more closely inversely proportional to the speed/density of the solar wind than the sunspot count?
Of all the solar variations, the solar wind speed/density has the least to do with cosmic ray modulation. A cosmic ray spirals around magnetic field lines. If those are smooth, the cosmic ray can make its way into the inner solar system. If the field lines have kinks or are turbulent, the cosmic rays are scattered and some of them [a few percent depending on energy] are scatted back out of the solar system and don’t reach us, hence the modulation. The magnetic field strength, B, has something to do with this and the modulation shows a reasonable correlation with B, which in turn is well correlated with the sunspot count. But the real modulator is the warp of the heliospheric current sheet as John Wilcox and I explained in our 1976 Nature paper. If the HCS is strongly warped [at sunspot maximum] the scattering is at a maximum and we see fewer GCRs. At solar minimum the HCS is rather flat and the modulation is least
~
Thanks Dr. S.
@Paul Vaughan says:
December 26, 2011 at 4:15 am
“And of course there are still people not realizing that solar excitation can be either CONstructive or DEstructive,”
On what exactly ?
Unhappily, I am still no wiser.
Can someone explain the meaning of this correlation between the first derivative of the length of day and the neutron count, and how this is so very difficult to calculate? And why is it so important?
Please do not use optical terms such as “focus” and “focal length” where they cause confusion rather than enlightenment. I don’t know how focus comes into Fourier Transforms. Is it an analogy?
What are these chaps getting so wound up about?
Leif Svalgaard says:
December 26, 2011 at 10:49 am
[lot-o-stuff clipped for brevity]
“…
Juraj V. says:
December 26, 2011 at 10:22 am
AFAIK, LOD is well correlated with Pacific trade winds, which dictate the ENSO conditions, which.. the rest is history.
Indeed it is and Gross finds precisely that. Furthermore he shows that the dedacal signal in LOD is caused primarily by core-mantle boundary processes.”
Wasn’t that in this paper?
http://geodesy.eng.ohio-state.edu/course/refpapers/Gross_Geodesy_LpER07.pdf
Does LOD correlate with frequency of earthquakes of a chosen magnitude?
Nice animations, Paul
At the beginning of the discussion, Leif said the correlation in graph 1 broke down prior to the start of the graph, calling it cherry picked. Without knowing why, is it not interesting that this is coincident with the loss of temperature and tree ring correlation? What shifted then?
“The amplitude of Earth’s zonal winds is modulated by the solar cycle”
1. You still haven’t said what the implication of this are. Why do you think it is so important?
2. Even though you have found seemingly nice correlations, that does not imply causality (which you imply in the statement above).
Both could be being forced by something else.
jorgekafkazar (December 26, 2011 at 7:24 pm)
“Nice animations, Paul”
That’s the spirit. Thanks jorgekafkazar.