From the American Geophysical Union weekly highlights:
Key Points
- Minimum 23-24 showed recurrence intervals of 9.0 and 6.7-d
- Historical geomagnetic activity data show that minimum 23-24 was unusual
- The heliosphere during minimum 23-24 had unusual sectorial structure
Since the mid-1800s, scientists have been systematically measuring changes in the Earth’s magnetic field and the occurrence of geomagnetic activity. Such long- term investigation has uncovered a number of cyclical changes, including a signal associated with 27-day solar rotation. This is most clearly seen during the declining phase and minimum of each 11-year solar cycle, when the Sun’s magnetic dipole is sometimes tilted with respect to the Sun’s rotational axis. With the Sun’s rotation and the emission of solar wind along field lines from either end of the solar magnetic dipole, an outward propagating spiral-like pattern is formed in the solar wind and the interplanetary magnetic field that can drive 27-day, and occasionally 13.5-day, recurrent geomagnetic activity. Recurrent geomagnetic activity can also be driven by isolated and semipersistent coronal holes, from which concentrated streams of solar wind can be emitted.
During the most recent solar minimum, which took place from 2006 to 2010, however, several researcher groups noticed 6.7-day and 9-day recurrent changes in geomagnetic activity, and similar patterns in the interplanetary magnetic field, and the solar wind.
Using modern data covering the previous two solar minima, these higher-frequency occurrences were judged to be unusual. Love et al. analyzed historical geomagnetic activity records from 1868 to 2011 and find that the 6.7-day and 9-day recurrent changes were actually unique in the past 140 years. They suggest that the higher-frequency changes in geomagnetic activity are due to an unusual transient asymmetry in the solar dynamo, the turbulent, rotating plasma deep within the sun which generates the magnetic field.
Source: Geophysical Research Letters, doi:10.1029/2011GL050702, 2012
http://dx.doi.org/10.1029/2011GL050702
Title: Geomagnetic detection of the sectorial solar magnetic field and the historical peculiarity of minimum 23-24
Authors: Jeffrey J. Love and E. Joshua Rigler: Geomagnetism Program, U.S. Geological Survey, Denver, Colorado, USA;
Sarah E. Gibson: High Altitude Observatory, NCAR, Boulder, Colorado, USA.
Abstract:
Analysis is made of the geomagnetic-activity aa index covering solar cycle 11 to the beginning of 24, 1868–2011. Autocorrelation shows 27.0-d recurrent geomagnetic activity that is well-known to be prominent during solar-cycle minima; some minima also exhibit a smaller amount of 13.5-d recurrence. Previous work has shown that the recent solar minimum 23–24 exhibited 9.0 and 6.7-d recurrence in geomagnetic and heliospheric data, but those recurrence intervals were not prominently present during the preceding minima 21–22 and 22–23. Using annual-averages and solar-cycle averages of autocorrelations of the historical aa data, we put these observations into a long-term perspective: none of the 12 minima preceding 23–24 exhibited prominent 9.0 and 6.7-d geomagnetic activity recurrence. We show that the detection of these recurrence intervals can be traced to an unusual combination of sectorial spherical-harmonic structure in the solar magnetic field and anomalously low sunspot number. We speculate that 9.0 and 6.7-d recurrence is related to transient large-scale, low-latitude organization of the solar dynamo, such as seen in some numerical simulations.
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This can be easily linked to SUVs.
In fact the Sun’s remarkable stability over billions and billions of years has been broken by the increased IR emitted by the third planet in the Solar System, throwing off-balance the exquisitely delicate workings of millions of H bombs exploding every second.
If nations don’t pull themselves together and stop GHG emissions by tomorrow, capitalism is going to destroy the Galaxy and [that’s enough catastrophism for this century -Eds]
What?! I thought that solar science was settled?
Gotta love those “numerical simulations”!
It’s buzzing!
Interesting stuff…
What is the “take home”?
Kurt in Switzerland
I wonder if it would be safe to wonder out loud if a difference in the center of rotation of the system might cause some ‘slop’ and “transient asymmetry”… or if that strays too close to That Which May Not Be Said about all things solar and rotational…
Get real you wise guys, if you don’t buck up & stop GHG emissions, Klaatu & his mates from out there will come down & most likely (95% confidence level) give us all a jolly good ticking off, they may even wag the fingers at us, which would frankly be an insult too far, don’t you know! 😉
Don’t you just love all these things we’re suddenly discovering about the Sun? Amazing, who’d a thunk it!
Geomagnetic data show that the solar storms (since I started daily monitoring on 1/1/2011) are shifting magnetic pole from the northern Canada toward Siberia.
http://www.vukcevic.talktalk.net/Tromso.htm
We almost got the magic word “unprecedented” in there. Shame, it won’t qualify for AR5 without that (well it’s too late anyway, I know).
Seriously what is unprecedented is the low level of activity of this minimum. I’m not sure that this finding is anything more exciting that saying when there’s less noise you can spot small amplitude signals that otherwise get drowned out.
As the 29d cycles are only seen during minima , the yet smaller amplitude 13.5d cycles are only detectable during very low minima.
Interesting stuff though.
The abstract is a tease, but I have questions that might be answered in the full article.
“Previous work has shown that the recent solar minimum 23–24 exhibited 9.0 and 6.7-d recurrence in geomagnetic and heliospheric data, but those recurrence intervals were not prominently present during the preceding minima 21–22 and 22–23. ”
Am I drawing the correct inference that improved instrumentation has been examined and ruled out?
“Using annual-averages and solar-cycle averages of autocorrelations of the historical aa data, we put these observations into a long-term perspective: none of the 12 minima preceding 23–24 exhibited prominent 9.0 and 6.7-d geomagnetic activity recurrence.”
I can’t see how any sort of improved data reduction technique can draw out information that wasn’t present to begin with. If these signals were lost in the noise, yes. But if they were too short to be recorded, or the variations were beyond the sensitivity of the instrumentation, I can’t see how they’d get the information, regardless of technique.
Could someone with access to the article comment, please.
Maurizio Morabito (omnologos) says:
March 19, 2012 at 3:14 am
>>
This can be easily linked to SUVs. In fact the Sun’s remarkable stability over billions and billions of years has been broken by the increased IR emitted by the third planet in the Solar System, throwing off-balance the exquisitely delicate workings of millions of H bombs exploding every second.
>>
You’ve hit the nail in the head. You know just this morning I was wondering how we could “ratchet” up the press for action and how we could up the anti from “save the world” to “SAVE THE UNIVERSE” ! And here’s the answer The Lord works in wondrous ways ….
This wonderful research shows how we are destabilising the SUN ! Even if it means giving up our entire way of life , our wealth , democracy and our freedom to a new world government (sorry “governance”) , we just don’t have any choice now, do we?
We must SAVE THE UNIVERSE !
Science is starting to pick up anomalies attached to SC24. The last time the Sun behaved like now was before we could measure anything, so everything is new. The “force that dare not speak its name” will eventually come to prominence, but unfortunately this may take some time.
The more we know…
I’ve wondered if coupling between the magnetic field and all those molecules whizzing around in jet streams could be one of Willis’s thermostats. Could that be another (long wave) mechanism for the earth to shed energy, outside of IR?
I don’t have the chops to answer the question.
Figures 2 & 3 are interesting:
http://www.agu.org/journals/gl/gl1204/2011GL050702/2011gl050702-op02-tn-350x.jpg
http://www.agu.org/journals/gl/gl1204/2011GL050702/2011gl050702-op03-tn-350x.jpg
Kurt in Switzerland says:
Interesting stuff…
What is the “take home”?
+1
Geoff Sharp says:
March 19, 2012 at 4:51 am
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Quite so.
When you are dealing with a system that is about 4.5 billion years old (OK Earth’s climate is somewhat less old), it is impossible to say what is new and what is unprecedentd.
Our snapshot is far to short to draw amy such far reaching conclusions.
Just added spectral response for the Ap max as measured at Tromso.
http://www.vukcevic.talktalk.net/Tromso.htm
Michael Larkin says:
Kurt in Switzerland says:
Interesting stuff…
What is the “take home”?
+1
———————————————
My takeaway is: Another data point that demonstrates the concept of a “solar constant” is fundamentaly flawed and any model or theroy of terrestrial climate that assumes so is also fundamentaly flawed.
I suspect this is just the build up to an explanation for why the world is not warming. The Sun’s unprecedented shivers trump global warming’s unprecedented fever. But when the shivers are over the fever will still be there so we still need to give them lots of our money.
Basically, the sun usually resonates with a 27 day period and a first harmonic of 13.5 days. Internal changes in the sun have stimulated the 2nd and 3rd harmonics with periods of 9 and 6.7 days respectively.
To visualize the vibrations, imagine a sphere sliced like orange wedges. The fundamental (27 day) has one slice, pole-to-pole in half, the first harmonic is sliced in quarters, the second harmonic is sliced pole-to-pole in sixths, and the third harmonic is sliced pole-to-pole in eighths.
The sectors vibrate alternately in and out, with adjacent sectors vibrating out of phase with each other.
http://panaworks.com/lana/fun/spheres.htm
we would have more fun (& interest) if they reported on the recent Forbush-cloud relationship.
Isn’t anyone bothered to find out results, or do we have to wait two years for a paper for someone ‘fit in the data to a model’?
If I’m reading the graphs correctly, was there also a relatively low average during the period when the US experienced the dust bowl, depression, etc.?
The appearance of a 9 day cycle is somewhat worrying. Why ? While the 13.5 and 6.7 day cycles clearly have 2 and 4 cycles within the principle cycle respectively, the 9 day cycle has 3.
Those who are familiar with chaos theory will know that the name ‘chaos’ comes from a classic 1975 paper (http://www.its.caltech.edu/~matilde/LiYorke.pdf) entitled ‘Period three implies chaos’. The authors proved that any system that shows a regular cycle of period three will also show cycles of every other period, as well as completely chaotic behavior.
richard verney says:
March 19, 2012 at 5:08 am
I was thinking along the same lines. Man has been measuring the sun for less than 200 years out of the [billions] that it has existed. We know there are limitations to the variance (cycles) or we wouldn’t be here, but what are those limitations? Some great observations. I don’t know if there is a ‘take home’ other than … “looks what it’s doing now!”