It has been awhile since I’ve looked at the Ap Index. The last time was April of 2009.
From the data provided by NOAA’s Space Weather Prediction Center (SWPC) you can see just how little Ap magnetic activity there has been since. Here’s my graph from September 2009 SWPC Ap data:
For a longer perspective, David Archibald, has a graph of the Ap Index back to 1932. The solar average geomagnetic planetary index, in Dec 2008, Ap was at its lowest level in 75 years:
Click for a larger image – I’ve added some annotation to the graph provided by Archibald to point out areas of interest and to clarify some aspects of it for the novice reader.
The last time the Ap index was this low was 1933. The December 2008 Ap value of 2,, has never been this low. (Note: Leif Svalgaard contends this value is erroneous, and that 4.2 is the correct value – either way, it is still lower than 1933) Further, the trend from October 2005 continues to remain low, though some signs of a slight rebound are showing.
This Ap index is a proxy that tells us that the sun is now quite inactive, and the other indices of sunspot index and 10.7 radio flux also confirm this. The sun is in a full blown funk, and your guess is as good as mine as to when it might pull out of it. So far, predictions by NOAA’s SWPC and NASA’s Hathaway have not been near the reality that is being measured.
As Leif Svalgaard points out, Ap is just one of several indices that describe geomagnetic activity. There are several others [aa, am, IHV, …] that go much further back in time [to the 1840s]. You can get more info from:
http://www.leif.org/research/IAGA2008LS.pdf and
http://www.leif.org/research/Seminar-UCLA-ESS288.pdf
For those that follow the sunspot number (SSN) I’ve graphed the Ap and SSN together. As you can see, we’ve been in a reduced state of solar activity now for quite some time. It has been almost 4 years since the prominent drop in Ap in October 2005. SSN mirrors the decline of the Ap index since then.
As many regular readers know, I’ve pointed out several times the incident of the abrupt and sustained lowering of the Ap Index which occurred in October 2005. The abrupt step change seemed (to me) to be out of place with the data, and since then the data seems less “active”, with reduced amplitudes. And then we have the fact that the sun seems to have reestablished at a lower plateau of the Ap index after that October 2005 step change and has not recovered now in almost 4 years. It seems to me to be a noteworthy event.
UPDATE: Thanks to Leif Svalgaard, we have a more extensive and “official” Ap dataset (NOAA’s SWPC has issues, see comments) that I’ve plotted below. The step change in October 2005 is still visible and the value of 3.9 that occurred in April of this year is the lowest for the entire dataset.
And I’ve also plotted the 1991 to present data from BGS/Svalgaard to compare against the NOAA SWPC data:
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rbateman (13:23:05) :
Just the part from 2005 onwards. I would like to see Anthony’s step function as well as where we currently sit, properly corrected.
I did from 1991 on, to be comparable with the other Figures:
http://www.leif.org/research/Ap-since-1991.png
pyromancer76 (13:58:12) :
complete downloadable Ap dataset file exists somewhere from these folks, feel free to point it out and I’ll plot it. – Anthony
http://www.leif.org/research/Ap-index-monthly-means.txt
REPLY: Thanks. Just out of curiosity, does the source offer such a complete dataset? – A
“Be civil or be snipped” lol — could fit a number of contexts…
I hope this is civil.
Anthony,
Awhile back you promised an updated graph of CO2 concentration vs temp. rise. Did I just not see that or are you still working on it?
REPLY: This one is a larger project than I expected, still working on it. -A
Leif,
As I understand them, Svensmark, Shaviv et al claim that the significant galactic cosmic rays for low cloud formation are only the high energy ones that produce energetic muons that can penetrate deep into the lower atmosphere. They further claim that variations in the strength of the earth’s geomagnetic variability do not affect these high energy cosmic rays much at all, while variations the strength of the solar magnetic field do. Am I wrong in that? If not, citing data on total cosmic ray flux does not really address the validity of their hypothesis does it?
Leif Svalgaard (14:22:22) :
REPLY: Thanks. Just out of curiosity, does the source offer such a complete dataset? – A
No, but I have had one for a long time. The official dataset has three-hourly resolution. So, one loads that one [can be found in many places] and then calculates the monthly means. The monthly mean table I don’t think is out there, except mine 🙂
Peter Hartley (14:38:44) :
They further claim that variations in the strength of the earth’s geomagnetic variability do not affect these high energy cosmic rays much at all, while variations the strength of the solar magnetic field do.
In both cases it is a magnetic field that deflect the cosmic rays. This deflection is inversely to the energy of the cosmic ray, high-energy rays are deflected least, so the solar modulation is mostly of the low-energy rays.
Leif Svalgaard (14:12:05) :
Thanks. The 2005 step function is still there. I’ll see what I can cook up from here.
Leif. In your 1991 to present Ap plot what does “demodulated” refer to?
wattsupwiththat (15:26:15) :
Leif. In your 1991 to present Ap plot what does “demodulated” refer to?
There is a semiannual modulation of Ap due to the geometry of the interaction between the Sun and the Earth. At the solstices, the interaction is reduced and Ap is reduced about 20%, so if one wants to use Ap as an indicator of solar activity, this reduction must be corrected for. So, in December 2008, Ap was not 4.5, but rather 5.8. The demodulated graph has this correction.
rbateman (15:21:41) :
Thanks. The 2005 step function is still there. I’ll see what I can cook up from here.
The ‘step’-function does not have any particular significance. It is caused by a single strong geomagnetic storm period centered on Sept. 11, 2005, click
that makes that monthly mean stick up.
Leif,
If Livingston and Penn are correct that means that Leif, Hathaway, Jansseen, Archibald, Hoyt are wrong. Do we start over or say what in the present physical model of the sun can explain this. I am looking at this from a “Re-Do” perspective and not attacking anyone. The current model is wrong, needs “tweeking”, right but an unknown observed effect? I just don’t known myself looking at this from a clean perspective.
Leif 15:09:29
Shaviv, for example, claims that the Earth’s magnetic field only stops cosmic rays below 10GeV in equatorial regions, and lower energies at the polar regions. He further says these rays are not strong enough to produce charged particles in the lower atmosphere, so even if we had no geomagnetic field the atmosphere would still shield us from these GCR. As you say, however, that should also mean variations in the sun’s magnetic field strength also do not affect the high energy cosmic rays. Reading more, I see that I also was wrong in claiming that Shaviv, Svensmark et al attribute attenuation of the energetic cosmic rays to the solar magnetic field. It seems they actually claim the solar wind does it. Do we have readily available measures of the strength of the solar wind?
John (13:17:02) :
If the Ap index indicates a cooler sun, AND if a cooler sun translates to a cooler climate on earth (as implied in the second figure in the ” 70s cooling period” caption)
There wasn’t a “70s cooling period”. The cooling began in the 1940s and ended in the 1970s. Temperatures actually began to rise in the 1970s.
Jim Arndt (15:54:45) :
If Livingston and Penn are correct that means that Leif, Hathaway, Jansseen, Archibald, Hoyt are wrong…
L&P do not say that solar activity will go away, just that sunspots will be invisible because their magnetic field is [just?] below a value where the contrast is one. You see, magnetic fields below 1800 Gauss [or so] are bright, and above 1800 G are dark, so right at 1800 G, they cannot be seen, but they are still there. The solar cycle is still going, the dynamo is still working. No ‘re-do’ is needed.
A sunspot is formed by coalescence of many magnetic flux elements. The elements are created by the dynamo and the L&P effect may be related to the process that compacts the elements to form a spot. Ken Schatten has some ideas about this: http://www.leif.org/research/Percolation%20and%20the%20Solar%20Dynamo.pdf
Peter Hartley (15:59:26) :
It seems they actually claim the solar wind does it. Do we have readily available measures of the strength of the solar wind?
It is the magnetic field of the solar wind that deflects the cosmic rays, so indirectly it is just the solar magnetic field. We have a good idea about what the magnetic field of the solar wind has been the last ~170 years: http://www.leif.org/research/IAGA2008LS-final.pdf
We’ve got another one with no idea what the notion of free speech means.
Leif Svalgaard (12:35:44) :
“James F. Evans (12:02:55) :
Which is it at this point in time? [state of Science]
Clearly healthy!”
“magnetic reconnection” — “The problem is, researchers can’t explain it.”
“‘Something very interesting and fundamental is going on that we don’t really understand — not from laboratory experiments or from simulations,’ says Melvyn Goldstein, chief of the Geospace Physics Laboratory at NASA’s Goddard Space Flight Center.”
http://science.nasa.gov/headlines/y2009/31aug_mms.htm?list1065474
Leif Svalgaard (paraphrase): “magnetic reconnection happens, those that challenge it are pseudo-scientific”
Many scientists say AGW is established scientific fact and those that challenge it are pseudo-scientific.
No, Dr. Svalgaard, I beg to differ in your assessment.
But perhaps where you stand depends on where you sit.
http://wattsupwiththat.com/2009/06/23/archibald-the-ap-index-says-there-will-be-no-sunspots/
TomLama (08:00:36) :
“The Sun is bleeding magnetic flux (for a very good reason), so I don’t think so.”
Hi David,
I missed the “very good reason” of why the sun is bleeding magnetic flux. Do you mind repeating it for those of us who missed it?
Leif Svalgaard (08:17:55) :
TomLama (08:00:36) :
“The Sun is bleeding magnetic flux (for a very good reason), so I don’t think so.”
I missed the “very good reason” of why the sun is bleeding magnetic flux. Do you mind repeating it for those of us who missed it?
Might be hard to do [so I’m also curious]. The Sun is not ‘bleeding’ magnetic flux. On the contrary, the new cycle activity is adding flux to the photosphere.
Ahhhh……hemmm….hawwwwhhhh….
Questions for thee but not for me, eh Leif?
Seems to me that the entire point of this thread is that, in fact, the sun is indeed bleeding solar flux.
“This Ap index is a proxy that tells us that the sun is now quite inactive, and the other indices of sunspot index and 10.7 radio flux also confirm this. The sun is in a full blown funk, and your guess is as good as mine as to when it might pull out of it. So far, predictions by NOAA’s SWPC and NASA’s Hathaway have not been near the reality that is being measured.”
All I have been doing is not so humbly asking for someone to put up. I never asked them to shut up. I do not have the editorial skills of Wattsupwiththat. As a fan all I ask for is some simple answers to basic questions.
The questions have been asked, and censored, and not answered.
Only you have the discresion to allow them to be openly aired.
“REPLY: OK now that you’ve admitted your error, phrase the questions minus the snark in a civil manner, and then they’ll be worthy of attention. – A”
Repeat my questions to Leif without the snark then.
You scientists are a touchy bunch, eh?
REPLY: All I’m asking you to do is put your questions in a simple set like this:
1. Question a
2. Question b
…
X Question x
Why? They also don’t exist anymore. They were deleted along with your snark and ad homs. If you want answers, then please ask the questions. If you just want to toss snark please go elsewhere. It is just that simple.
– Anthony
Further to the comment at 15:59:26
Reading some more, I see that Svensmark does talk about the solar magnetic field too, but it is not the strength of the solar magnetic field in the vicinity of the earth that he discusses but rather its strength at the heliopause where, he claims, most of the high energy galactic cosmic rays are deflected. The strength of the geomagnetic field would be irrelevant to this. I think your comparison, Leif, of the relative strength of the solar and earth magnetic fields was only in the vicinity of the earth. Svensmark seems to say that the solar wind somehow carries the solar magnetic field to the heliopause, but I am not sure how that happens if it is as weak as you say.
John Finn (15:59:48) :
There most certainly was a cooling scare in the 70’s, and some rather prominent figures are common to today’s scare.
There was also an extended plateau of elevated neutron monitor counts for the 70’s. The plateau, however, did not reach the heights of today’s levels. There was another extended (but more rounded) plateua in the 90’s. In between cycles are sharp peaks. Expectations of a rapid plunge to this cycle prior to experiencing a plateau would break the mold.
Will it be broken?
Peter Hartley (16:41:19) :
Svensmark seems to say that the solar wind somehow carries the solar magnetic field to the heliopause, but I am not sure how that happens if it is as weak as you say.
The solar wind carries the sun’s magnetic field all the way from the sun to the heliopause. On its way it passes by the Earth where we can measure it.
The relative strength of the solar wind magnetic field and the Earth’s magnetic field is not relevant, because the deflection of cosmic rays by the two fields is done by different mechanisms.
James F. Evans (16:31:27) :
“magnetic reconnection happens
Goldstein did not say that he [we] doubt that it happens [because reconnection is observed] just that we do not understand the details.
Leif Svalgaard (12:22:29) :
The Sun’s magnetic field modulates the cosmic rays [GCR], and the Earth’s magnetic field does as well. The latter modulation is much larger than the former. From 5000 BC to 500 AD, the Earth’s field was increasing and GCRs were therefore decreasing, and temperatures should have increased, but they decreased instead. That change of the GCR flux was ten times larger than that the Sun causes.
This statement is disingenuous, there are just as many records showing the earth cooled 7000 years ago compared with the earth warmed 7000 years ago. I dont think we can be too confident about temperature records that far back.
Also the GCR effect is just one “possible” component of a climate regulator. There is the separate solar contribution to the GCR shielding along with TSI and UV factors that need to be included, there may be other factors not known of course.
7000 & 5500 years ago there was a very similar period of heavy grand minima like we have just recently came out of.
http://www.landscheidt.info/images/c14nujs1.jpg
Jim Arndt (15:54:45) :
Leif,
If Livingston and Penn are correct that means that Leif, Hathaway, Jansseen, Archibald, Hoyt are wrong. Do we start over or say what in the present physical model of the sun can explain this. I am looking at this from a “Re-Do” perspective and not attacking anyone. The current model is wrong, needs “tweeking”, right but an unknown observed effect? I just don’t known myself looking at this from a clean perspective.
Solar science is definitely in a messy place right now. The failed Babcock-Leighton model is the root cause in my opinion.
rbateman (16:58:53) :
There was also an extended plateau of elevated neutron monitor counts for the 70’s. The plateau, however, did not reach the heights of today’s levels. There was another extended (but more rounded) plateua in the 90’s. In between cycles are sharp peaks.
Thule [in Northern Greenland] has monitored the neutron count since the 1950s:
http://www.leif.org/research/thule-cosmic-rays.png
At the present time we are at one of the sharp peaks.
Geoff Sharp (17:15:53) :
This statement is disingenuous, there are just as many records showing the earth cooled 7000 years ago compared with the earth warmed 7000 years ago.
It is not about the single year 7000 years ago, but about the trend since. Here is one compilation:
http://en.wikipedia.org/wiki/File:Holocene_Temperature_Variations.png
The word ‘disingenuous’ is not appropriate in serious discussion.
There is the separate solar contribution to the GCR shielding
Please elaborate
Geoff Sharp (17:19:40) :
The failed Babcock-Leighton model is the root cause in my opinion.
The B-L model predicts a weak cycle 24, so cannot be said to have failed.
Ah, rounded and sharpened peaks, my favorite. I still think there is going to be two of one type of peak and one of the other in each phase of the PDO, and that the correlation will harbor causation. But these are very weak effects, as I’ve been reminded repeatedly by Leif.
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