While sunspots are often cited as the main proxy indicator of solar activity, there is another indicator which I view as equally (if not more) important. The Average Planetary Magnetic index (Ap), the strength of which ties into Svensmark’s cosmic ray theory modulating Earth’s cloud cover. A weaker Ap would mean less cosmic rays are deflected by the solar magnetic field, and so the theory goes, more cosmic rays provide more seed nuclei for clouds in Earth”s atmosphere. More clouds mean a greater albedo and less terrestrial solar radiation, which translates to lower temperatures.
I’ve always likened a sunspot to what happens with a rubber band on a toy balsa wood plane. You keep twisting the propeller beyond the normal tightness to get that extra second of thrust and you see the rubber band start to pop out knots. Those knots are like sunspots bursting out of twisted magnetic field lines.
The Babcock model says that the differential rotation of the Sun (the sun being a viscous fluid, the poles rotate at a slower rate than the equator) winds up the magnetic fields of it’s layers during a solar cycle. The magnetic fields will then eventually tangle up to such a degree that they will eventually cause a magnetic break down and the fields will have to struggle to reorganize themselves by bursting up from the surface layers of the Sun. This will cause magnetic North-South pair boundaries (spots) in the photosphere trapping gaseous material that will cool slightly. Thus, when we see sunspots, we are seeing these areas of magnetic field breakdown.
Sunspots are cross connected eruptions of the magnetic field lines, shown in red above. Sometimes they break, spewing tremendous amounts of gas and particles into space. Solar flares and coronal mass ejections (CME’s) are some examples of this process. Sometimes they snap back like rubber bands. The number of sunspots at solar max is a direct indicator of the activity level of the solar dynamo.
As many of you may recall, a few months ago, I had plotted the Average Geomagnetic Planetary Index (Ap) which is a measure of the solar magnetic field strength but also daily index determined from running averages of eight Ap index values. Call it a common yardstick (or meterstick) for solar magnetic activity.
Click for a larger image
I’ve updated the graph today, to include July 2008 Ap data as you can see below:
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Source data, NOAA Space Weather Prediction Center:
http://www.swpc.noaa.gov/ftpdir/weekly/RecentIndices.txt
As you can see, the Ap Index has continued along at the low level (slightly above zero) that was established during the drop in October 2005. As of July 2008, we now have 34 months of the Ap hovering around a value between 5 to10, with occasional blips of noise.
Since it is provided in the same dataset, I decided to also plot the smoothed Ap Index.
I also plotted my own 24 month smoothing window plot, shown in magenta.
Click for a larger image
I also decided to update the plot of the 10.7 centimeter band solar radio flux, also a metric of solar activity. It is in the same SWPC dataset file as the Ap Index, in columns 8 and 9. The smoothed 10.7 CM flux value provided by SWPC has also dropped about the same time continues a downward trend.
I also provided my own 24 month wind smoothed value which is plotted in magenta.
Click for a larger image
Note the lower flux values during this solar minimum than the last
We continue to remain in a deep solar minimum, and with the forecasts being modified to push back the real “active” start of Solar cycle 24, it remains anybody’s guess as to when the sun will come out of it’s funk.
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@Robert Wood & Leif Svalgaard
David Hathaway is a proponent of the belt model for solar activity. I think he can provide that data and is very forth right in his communications. His email is accessible from his NASA solar page.
Dee Norris (20:48:22) :
David Hathaway is a proponent of the belt model for solar activity. I think he can provide that data and is very forth right in his communications. His email is accessible from his NASA solar page.
David Hathaway is a friend and colleague of mine and we both serve on NOAA/NASA’s Sunspot Prediction Panel. I have asked him many times to provide that data and to no avail. Either the data does not exist or it shows something that is not palatable to him or his institution… You can try to ask him using the email address on his NASA solar page and tell us the result.
Link to the Hathaway comments about the conveyor belt.
http://science.nasa.gov/headlines/y2006/10may_longrange.htm
“Normally, the conveyor belt moves about 1 meter per second—walking pace,” says Hathaway. “That’s how it has been since the late 19th century.” In recent years, however, the belt has decelerated to 0.75 m/s in the north and 0.35 m/s in the south. “We’ve never seen speeds so low.”
That was 2006.
Lucy Skywalker,
You said: “Rhodes Fairbridge reckons the Sun’s level of activity is affected by the big planets moving the solar system’s centre of gravity – when it’s outside the Sun, the Sun loops, and this “chaotic” movement tends to stop the magnetic fields winding up – if I’ve understood this right.”
When you learned about certain models in school, the model was “good enough” to help you understand the material at that level. However, not everything taught carries over to more advanced problems– those models are no longer “good enough”.
The point in case here is the center of gravity from Newtonian physics. It is “good enough” to understand a one or two body problem. But when you look at a many body problem you’ll naturally notice that there would need to be extra forces to explain some strange behavior. These forces are only an artifact of the model being used.
Newton’s theory of gravitation was replaced with General Relativity. In GR, these forces do not exist. It is a case of the model you understand not being “good enough” for the purpose you want to use it.
Response to Michael J. Bentley (10:23:08) :
Perhaps that’s what they want. The argumanet is there are too many people for the planet to sustain.
@Lief
Didn’t realize your connection.
Isn’t this supposed to be publicly-owned data?
Well, I guess I have to take a stab at getting it.
Thanks.
Thanks Anthony for the post, especially as it points up the obvious fact that these proxies(SS, 10.7cm, AP) for solar activity are not equivalent, but arise as effects of an apparent common cause, which we, in part, conclude from the similarity of the graphs following smoothing.
“What is important on the Earth for society is the flux observed at Earth, because that is the one that determines satellite drag and radio communications, so that is the one SWPC will report.”
I don’t understand why this does not suffice as justification for publishing the SWPC data as is. Is this a ‘Solar Blog’ run for solar physicists?
For that matter, why would one publish TSI from 1 AU in preference to TSI at the earth?
To me, this is an earth-centric forum and I like it that way.
The spots locale is the sun, the AP’s locale is the earth, no adjustment is necessary. Where the radio flux or TSI is taken is a matter of preference and common interest not prescription.
We are capable of understanding this difference, but solar activity at the earth is my preference as it is more meaningful.
Ranting Stan (00:19:43) :
In recent years, however, the belt has decelerated to 0.75 m/s in the north and 0.35 m/s in the south. “We’ve never seen speeds so low.
That was 2006.
And the ‘recent years’ he refers to is 2000-2003. Dikpati et al.’s 2006 paper says that they “expect the next cycle to to 30% or 50% higher”. The reason for the two numbers is that they estimates of the ‘belt’ speed up to the year 2003 and did not know what the speed was after that or how it would change in the next few years. So based on two different assumptions about how it would change, they came up with two different predictions. Now it is five years later. If new data up to the present existed, that new data should have told them which way the change [if any] went and should have enabled them to refine the prediction, or at least to select one or the other of the earlier choices. They have not done that because no new data has been forthcoming. The NOAA/NASA Panel on Sunspot Prediction has repeatedly urged that new data be produced and the model rerun with up-to-date input, but this has not happened.
More on the ‘conveyor belt’ speed: The ‘scientific’ term is the ‘Meridional Circulation’ [abbrev. MO], but ‘conveyor belt’ has become popular because of its more descriptive qualities. The MO can be observed at the surface in two ways, 1: drift of sunspots in latitude, and 2: direct measurement of plasma flow using the Doppler effect. A typical value for MO is 20 m/s at mid-latitudes. [I don’t know where Hathaway gets ~0.5 m/s from]. Inside the Sun, the MO can be probed using helioseismology, but those measurements do not extend very deep [yet] and the return flow at the base of the convection zone has never been observed. The return flow is much slower than the surface flow because the plasma density is much higher. The speed of the MO sets the length of the solar cycle in most dynamo models. The slower the speed, the longer the cycle. In fact, they are inversely proportional: Length (years) = 200 / (speed in m/s). [Try to insert Hathaway’s 0.5 m/s and see what the cycle length becomes…].
Gary Gulrud (04:12:28) :
For that matter, why would one publish TSI from 1 AU in preference to TSI at the earth?
Nobody shows plots of TSI at the Earth [show me one]. TSI is always reduced to 1 AU, because that is the relevant parameter when discussing solar changes. You have probably heard that TSI changes 0.1% over the solar cycle and people wonder how much climate impact that has. TSI changes 70 times as much over the year, but that you never hear about.
We are capable of understanding this difference, but solar activity at the earth is my preference as it is more meaningful.
You preference is your own as you see fit, but in a discussion about what the Sun is doing, the Earth doesn’t matter. After all, the title of this topic is “The Sun is in a magnetic flunk”, not “Over the past three months we have been farthest from the Sun”.
In the end, I think Anthony plotted the ‘observed’ values simply because he did have handy the ‘adjusted’ values that he really wanted to plot.
Leif,
“Nobody shows plots of TSI at the Earth [show me one]…TSI changes 70 times as much over the year, but that you never hear about.”
Thank you, for every word.
“but in a discussion about what the Sun is doing, the Earth doesn’t matter”.
Tell us what point Anthony made or inferrence expected or the reader that is facilitated by your “adjusted data”? The data isn’t ready for his use because it is so infrequently considered at all. Rather like your argument above, ‘eh?
In the former case any one like Bob Tisdale or Erl Happ or Dave Archibald can prepare graphs of solar TSI at the earth, resulting Insolation (before albedo is accounted for), etc., because of their interest in climate. This is hardly as arcane a use as 10.7 cm flux, adjusted post fact, for point of origin.
Speaking only for myself, I come here because this is a Weather/Climate blog that investigates the periphery. If a point is made about the sun so much the better. I think you are overstepping here, Sir.
Gary Gulrud (10:17:59) :
Tell us what point Anthony made or inferrence expected or the reader that is facilitated by your “adjusted data”?
Anthony said:
I also decided to update the plot of the 10.7 centimeter band solar radio flux, also a metric of solar activity.
He clearly intended to plot a metric of solar activity, not of the variation of the distance to the Sun.
I think you are overstepping here, Sir.
Sounds more like I’m stepping on some toes 🙂
Leif,
Expecting to come to this site with data formatted to your liking to no useful purpose is a tad obsessive don’t you think? The accuracy of your adjusted data, in this particular case, is not empirically established in real time for any region in space. Why the bother?
You tilt after windmills and hope to catch your adversary in some trivial misstep.
Again the interest of the plurality is in the role of solar activity re: climate. We acknowledge, we grant your point that variance in solar TSI at the photosphere is not sufficient to explain climate change. The implication, however, that this makes AGW a whit more plausible is daft.
REPLY: Gary, I’m in agreement with Leif on the adjusted data for 10.7cm flux. This adjustment is strictly about applying physical law, the inverse square law to measurement of the radio signal as the earth’s distance to the sun changes with orbit.
It is not some random and poorly designed machination like Jim Hansen’s adjustment of station data. If there was an easily plottable version of 10.7 cm adjusted dataset avilable, I’d have used it. So, cut Leif some slack please. – Anthony
I am reminded of Alexander the Great and the Gordian Knot. How long before someone puts this debate to bed?
Gary Gulrud (12:54:35) :
Expecting to come to this site with data formatted to your liking to no useful purpose is a tad obsessive don’t you think?
The correct data should be used; not for my sake, but for the sake of thousands of other readers [including you] that deserve a scientifically sound comparison.
The accuracy of your adjusted data, in this particular case, is not empirically established in real time for any region in space. Why the bother?
It is not ‘my’ adjusted data. The adjustment is made by the radio observatory that make the observations and is very, very accurate. You obtain the adjusted flux by dividing the observed flux by the square of the distance to the Sun [in AUs]. This number is known to 10 digit accuracy, about 10 million times more accurately than the flux measurement itself.
You tilt after windmills and hope to catch your adversary in some trivial misstep.
such ad-hom remarks are not appreciated and put you to shame.
The implication, however, that this makes AGW a whit more plausible is daft.
I think I found the toe. You are jumping to the wrong conclusion that the question about solar influence on climate has anything to do with AGW or anti-AGW, and that my opinion about the evidence for solar influence is based on or related to the AGW-debate.
This article is not exactly on topic but interesting nonetheless:
It is titled “Linkage Between Solar Activity, Climate Predictability, and Water Resource Development.” The authors see a link between sunspots and rainfall and the flow of the Vaal River in South Africa.
http://nzclimatescience.net/images/PDFs/alexander2707.pdf
David G. Mills (13:20:21) :
It is titled “Linkage Between Solar Activity, Climate Predictability, and Water Resource Development.” The authors see a link between sunspots and rainfall and the flow of the Vaal River in South Africa.
David, if I may be so blunt, the article is bunk.
Leif,
” You obtain the adjusted flux by dividing the observed flux by the square of the distance to the Sun [in AUs].”
The highly twisted IMF does not permit this to be other than a highly idealized representation, sorry.
While we will accept that this is the best we can do, you have not attempted to show why the consistent use of SWPC near-earth data is not as good or better than your adjusted data and moreover of more use to readers of disparate focus.
“ad-hom remarks are not appreciated and put you to shame”
Your characterization is inapt. The metaphor clearly follows from my assertion that the issue is overwrought. You disagree, fine.
Raphael – thanks, I’ll work on that – but it looks as if Carsten Arnholm has material on this issue here – just picked this up from the No Sunspots post.
Lief. Thanks. But since I am an attorney, not a scientist, could you explain why?
Lucy Skywalker,
If you only have a general knowledge of gravity, the idea can appear convincing. You have a level of understanding. You see strange behavior in that model that require extra forces to understand. It is natural to wonder what effect those forces have.
But, in GR the sun is in free fall moving along a geodesic. A geodesic is basically a straight line through curved space-time (4 dimensional space). Even though we perceive the sun doing some radical wiggles, the Sun is traveling in a “straight line” so no forces are required to explain the sun’s “strange” behavior. (No extra forces. No extra effects.)
Gary Gulrud (14:16:52) :
” You obtain the adjusted flux by dividing the observed flux by the square of the distance to the Sun [in AUs].”
The highly twisted IMF does not permit this to be other than a highly idealized representation, sorry.
You better be sorry, because the highly twisted IMF has absolutely no effect on F10.t which are electromagnetic waves getting to us in 8 minutes. I know, I cannot assume that everyone is versed in elementary science, and that it is our duty as scientists to provide the public with the information it deserves, one would recommend a little bit of restraint on your part when you are that far off the mark.
David G. Mills (15:53:46) :
Leif. Thanks. But since I am an attorney, not a scientist, could you explain why?
As an attorney you might appreciate that if one can show that a part of a witness’ statement is false, that casts doubts on the veracity of the rest.
Take a look at Figure 10. I have a link here for convenience. Note that the authors subscribe to the [unphysical] barycenter notion and compute the Total Solar Irradiance (TSI) at different seasons depending on where the Sun is with respect to the barycenter [TSI depends on the distance to the Sun – it varies 7% through the year]. The numbers they give (1417, 1365, 1350, 1385 W/m2) are plainly wrong. We have very accurate satellite measurements of the TSI that deviate very much from what the author’s understanding is. I have a plot here that shows the observed [black] and purported [red dots] TSI-values. There are other serious criticisms, but this one here shows their lack of understanding of basic science. I rest my case.
Leif – not being a scientist I have no opinion either way on the conveyor belt – I was just posting a link to to Dr Hathaway’s comments regarding it. I don’t pretend to understand it!
I suppose one could presume that Dr Hathaway continued to monitor the speed post 2003 – although I think he said in the article that he used the drift of sun spots to measure the speed, which must be a little tricky when there aren’t any sun spots!
If, as you say, this is how they determine the strength of the next solar cycle – or one of the factors – then I suppose the question should be – what is the conveyor doing now and if they have stopped measuring it post 2003 – then why?
Perhaps it is “normal” again – but if they won’t reveal the data how can anyone know?
To demonstrate why I’m not a scientist I tried using your idea to predict the length of the next cycle – Length (years) = 200 / (speed in m/s) – and came up with 400 years! Seems a little long to me 😉 – why 200 by the way? Even with normal speed of 1 m/s that would be 200 years. And I don’t know about anyone else, but I walk a damn sight faster than 1 m/s
Leif Svalgaard 13:44:52 “The article is bunk” (http://nzclimatescience.net/images/PDFs/alexander2707.pdf)
Those four little words made me… interested… so I looked further, and indeed, IMHO you cannot dismiss that easily the work of people of such obvious excellence as the five authors of this study. And when I looked further I found… once again, the “heretical” thesis involving the solar system barycentre that I’ve just flagged up TWICE now. Raphael, thanks for words that alerted me to this being a controversial issue. Leif, thanks for showing that people working right now take it seriously. This is the stuff of science…
I’m going to investigate this business further… beam me up Scottie…!