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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I think it is of interest to trace Leif’s comments in this thread on the Svensmark/Shaviv et al hypothesis. The original statement Leif was commenting on at 12:22:29 was:
Jewett (11:55:11) :
The increased cosmic rays results in increased clouds. The increased clouds increases the albedo of the earth, more energy from the sun is reflected into space and the earth cools.
which draws Leif’s comment:
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.
Then we had the comment at 14:03:02:
tallbloke (13:27:22) :
I think Leif is saying that the Earth’s geomagnetic variability has 10 x more effect on the level of the GCR flux at Earth’s surface Than the sun’s cyclic variability does.
which interpretation Leif confirms:
yep
I then pointed out at 14:38:44 that the GCR theory pertained only to high energy GCR, which are not affected by the geomagnetic field at all, and not those below 10GeV that are so affected. This would make the comment on the relative strengths of the geomagnetic and solar magnetic fields irrelevant to that theory. Leif then says:
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.
Note that this statement still does not directly contradict the Svensmark/Shaviv et al hypothesis. That the solar magnetic field “mostly” modulates the low-energy rays, and even then to a lesser extent than the geomagnetic field does, is irrelevant to what modulates the high energy cosmic rays, which is all that matters for the hypothesis. Knowing that Svensmark and Shaviv have actually discussed this issue I read some more and find that they talk about the solar wind and deflection at the edge of the solar system, not the vicinity of the earth. Thus, the relative strengths of the earth’s and sun’s magnetic field in the vicinity of the earth are also irrelevant to the hypothesis. Then at 17:10:49 Leif agrees:
The relative strength of the solar wind magnetic field and the Earth’s magnetic field is not relevant.
This leads me to ask why Leif commented on the Svensmark/Shaviv et al hypothesis by saying the earth’s magnetic field (measured in the vicinity of the earth) was 10x stronger.
Peter 18:39:19
That’s an excellent question, and I wish I understood enough physics to appreciate Leif’s response. So be careful and be clear Lief. I’d like to understand this matter, because it’s not unlikely that there are further clues in clouds and cosmic rays.
========================================
Leif Svalgaard (18:10:42) :
There is the separate solar contribution to the GCR shielding
—–
Please elaborate
As covered previously in this thread. From Peter HArtley
“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.”
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.
But not weak enough if we are indeed entering the [unnamed] Minimum, and only yours is close, the rest in the B-L camp have predicted a high cycle. The biggest failure of the B-L model is the inability to cope with regular solar grand minima which has now been confirmed by both solar proxy isotopes. No model of solar activity is correct unless it can explain the regularity of grand minima over the Holocene….its time to start again.
http://www.landscheidt.info/?q=node/51
[snip]
REPLY: Geoff, if you have an issue with WUWT, take it up with me directly. – Anthony
Every spring (around April or May) the Solar Cycle Prediction Panel meets to setforth their best predictions based on their own and solicited studies. We will have to wait until next spring to see what their best, educated pronouncements will be. Considering the current state of the sun, I don’t imagine it will do any good to meet any sooner. Hopefully a few more sunspots in the interim may start to define a ramp-up to SC24. If not, then all drawing boards should be busy – I would even call for an international conference on such.
Off-Topic Appeal
I am trying to locate some raw data for satellite spectroscopic measurements of the infra-red emission spectra of Venus, Earth, and Mars. Any pointers much appreciated!
To pyromancer76
You made me smile, thanks 🙂 Who are the other three in the gang? 🙂
Geoff Sharp (19:17:06) :
[snip]
REPLY: Geoff, if you have an issue with WUWT, take it up with me directly. – Anthony
I dont have an issue with WUWT and the comment wasn’t aimed at you or anyone in particular, I was just stating that sometimes you need to be diligent and do your own homework and not just take for granted what may be written.
Sometimes the whole truth is not stated.
WOW!!!!!!!!!!!
Hey if there is (and it looks like it from the grafts) a 3year AND a 6 year lag……. God help us.
And yes this is all I am saying today!
Leif, it’s getting interesting is it not?
Nite nite mods.
Steve (Paris) (09:58:27) :
Meanwhile Catlin has tapped WWF for cash to speed up ‘analysis’ of the data in time for Copenhagen. Why bother when we all know what that data will ‘reveal’?
…
Scientists are busy analysing data from the Catlin Arctic Survey. The data will provide important new evidence for the crucial climate negotiations in Copenhagen this December.
The Catlin Arctic Survey team returned this May with unique new measurements of the thickness and extent of sea ice in the Arctic.
Guaranteed to be unique, and never repeated (as not repeatable?! – a more or less random walk over shifting ice…).
Ah… the Catlin Arctic Survey team – I miss them, absurdist entertainment at its best.
Anthony: Your Oct 2005 step function has an interesting sidebar to it.
Apparently, that is when the Sun changed from having bands in the EIT going horizontal to another form best described as the clouds on Venus. Chevrons.
Those slanted bands have lost the coronal holes in the gap between the polar regions and the equatorial region, but they still remain to this day.
I’m not up to speed on how long it takes for changes on the Sun to show up in the AP index.
Someone may want to provide that.
It will take me some time to process all the images from 08/15 to 10/31 to show the progression.
You may want to dig on your own and see where this leads you.
REPLY: I’ll have a look, thanks. – A
Before I forget, there is a gap in EIT coverage from 09/03 to 09/23 for 2005.
Peter Hartley (18:39:19) :
This leads me to ask why Leif commented on the Svensmark/Shaviv et al hypothesis by saying the earth’s magnetic field (measured in the vicinity of the earth) was 10x stronger.
Not the field, but the modulation. http://www.leif.org/research/CosmicRays-GeoDipole.jpg shows the anticorrelation between 14C and the dipole moment. The tiny wiggles are due to solar modulation. The peak of 14C production is around 10 km altitude, so the cosmic rays have to be energetic enough to penetrate that far. As one goes to higher and higher energy, the cosmic rays become fewer and fewer [roughly by a factor of 1000 for each factor 10 in energy], so you cannot avoid the modulation problem by going to the highest energies, because there are so few of them and because they are also not modulated much by solar activity.
Geoff Sharp (19:07:24) :
“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”
The latter is in direct proportion to the former as the solar wind is carrying the same field past the Earth as ends up at the heliopause.
Geoff Sharp (17:19:40) :
only yours is close, the rest in the B-L camp have predicted a high cycle
There are not many in that high camp, and the difference between high and low is in the boundary conditions applied. The model is the same.
The biggest failure of the B-L model is the inability to cope with regular solar grand minima
The B-L model can easily deal with Grand Minima, e.g. http://www.leif.org/EOS/Choudhuri-Karak-2009.pdf
But if L&P are correct, the Grand Minima may not be so Grand as they appear just as an artifact of the visibility of sunspots while the dynamo was still working and the solar wind still blowing and cosmic rays still modulated almost as much as at other times.
noaaprogrammer (19:43:18) :
Every spring (around April or May) the Solar Cycle Prediction Panel meets to setforth their best predictions based on their own and solicited studies.
Our work is done this time around. No more meetings.
Geoff Sharp (20:57:09) :
I was just stating that sometimes you need to be diligent and do your own homework and not just take for granted what may be written.
Most of the stuff that are on the Internet is junk in the first place [to wit what you peddle] and does not pass a simple smell test. The rest, the readership will find flaws with. And the ‘truth’ is elusive anyway or perhaps not even known. One should be particularly suspicious of people ‘in the know’ that proclaim to have the truth.
rbateman (22:49:57) :
I’m not up to speed on how long it takes for changes on the Sun to show up in the AP index.
four days
Leif Svalgaard (23:13:00) :
What is your observation on the trend in open solar flux within this solar minimum?
maksimovich (23:30:58) :
What is your observation on the trend in open solar flux within this solar minimum?
Trend? within the minimum? over one or two years?
The value is better defined. The ‘open flux’ is ambiguous, but the Heliospheric Magnetic Field strength is well-defined. It is now the same as it was 108 years ago during the minimum between cycles 13 and 14.
Svalgaard (16:21:05) : We have a good idea about what the magnetic field of the solar wind has been the last ~170 years:
Dear Dr. Svalgaard,
Let us imagine that a scientist from outer space came and told us that the Svensmark theory is correct but that we have not managed to figure out all the details yet. Let us further assume that we then wanted to correlate the arctic temperature (A) the last ~100 years with the magnetic field of the solar wind (B),
A. http://climate4you.com/Polar%20temperatures.htm#NH%2070-90%20TempSince1900
B. http://www.leif.org/research/IAGA2008LS-final.pdf
The question is whether the reason to reject any correlation between these two quantities is that,
1. There is no correlation.
2. The data are not reliable.
3. The data set is too short.
BTW. the paper “Observatory Data: a 170-year Sun-Earth Connection” is very interesting.
rbateman (22:49:57) :
Oct 2005 step function
The sharp step is spurious [caused by a single active region in Sept, 2005], but there is a real lowering of the background level. This is related to a 22-year cycle in geomagnetic activity where the minima between even and odd cycles have stronger geomagnetic activity than the minima between odd and even cycles [e.g. the current minimum] have weaker geomagnetic activity. The generally accepted explanation of the reason for this cycle may be found in section 9 [page ~53] of http://www.leif.org/research/suipr699.pdf but there is probably a solar reason as well [e.g. http://www.leif.org/research/Asymmetric%20Rosenberg-Coleman%20Effect.pdf ]. A strong Rosenberg-Coleman effect has developed for the current minimum, supporting the traditional explanation. Bottom line: In addition to whatever solar changes there have been, there is terrestrial modulation as well, helping to make this minimum extra weak.
Invariant (23:44:21) :
The question is whether the reason to reject any correlation between these two quantities
The temperature graph shows the temperature between 70 and 90 degrees North. There is very little real data for the Near North Pole region especially the first 50 years of the graph, so one would start by examining that issue. In broad terms, the magnetic field (B) now is what it was in the 1901 and temps (A) are not, so the correlation does not seem to be there.
Invariant (23:44:21) :
the paper “Observatory Data: a 170-year Sun-Earth Connection” is very interesting.
The written paper is shorter than the original talk, which is here:
http://www.leif.org/research/IAGA2008LS.pdf
Geoff Sharp (20:57:09) “Sometimes the whole truth is not stated.”
Geoff, have you checked out the works of Yu.V. Barkin yet?
More on the Rosenberg-Coleman effect and the 22-year cycle in geomagnetic activity:
http://www.leif.org/research/Semiannual%20Variation%201954%20and%201996.pdf
Leif Svalgaard (23:40:06) :
Sorry wrong terminology,did not S and C 2007 suggest that a floor in B would result in a floor in open solar flux of 4×10^14 Wb ?. Have these “drifted’ or still sustained? Does McCracken (2007) need revisiting ?
Re: The Sun’s Heliosphere & Heliopause
http://apod.nasa.gov/apod/ap020624.html
“Where does the Sun’s influence end? Nobody is sure. Out past the orbits of Neptune and Pluto extends a region named the heliosphere where the Sun’s magnetic field and particles from the Solar Wind continue to dominate. The surface where the Solar Wind drops below sound speed is called the termination shock and is depicted as the inner oval in the above computer-generated illustration. It is thought that this surface occurs as close as 75-90 AU — so close that a Pioneer or Voyager spacecraft may soon glide through it as they exit the Solar System at about 3 AU/year. The actual contact sheet between the Sun’s ions and the Galaxy’s ions is called the heliopause and is thought to occur at about 110 AU. It is depicted above as the middle surface. The Sun’s heliopause moves through the local interstellar medium much as a boat moves on water, pushing a bow shock out in front, thought to occur near 230 AU.”
Even in its present weak state, the radius of the heliosphere is many AU.
maksimovich (00:21:15) :
Sorry wrong terminology
the Heliospheric Magnetic Field strength is well-defined. It is now the same as it was 108 years ago during the minimum between cycles 13 and 14. So, where ever the floor it is the same as back then.
Does McCracken (2007) need revisiting ?
http://www.leif.org/research/Comment%20on%20McCracken.pdf
McCracken was taking support from the old Lockwood 1999 paper about the doubling of the HMF. With Lockwood et al. now agreeing with us about the HMF not having doubled, the McCracken 2007 splicing of neutron monitor and ion chamber cosmic ray records is now not supported.