The NOAA SWPC monthly solar cycle update has been published here, and after a big spike last month, the sunspot count is down again. There’s an even bigger drop though in the Ap geomagnetic index, as seen and discussed below the Continue reading line.
10.7 centimeter radio flux was down slightly too.
But here’s the really interesting part, the Ap geomagnetic index plummeted to a value of 2, equal to the previous 12 year minimum set in November 2009.
Source data: http://www.swpc.noaa.gov/ftpdir/weekly/RecentIndices.txt
Dr. Leif Svalgaard offers these comments via email:
Ap is based on mostly Northern Hemisphere stations [11 North, 2 South] and is somewhat biased [having less activity in northern winter]. This is in addition to a general semiannual variation http://www.leif.org/research/Semiannual-Comment.pdf
with minima at the solstices. The definitive Ap values are determined by Potsdam and can be found here: http://isgi.latmos.ipsl.fr/lesdonne.htm
Real-time values [preliminary the last 15 days] are available here http://www.geomag.bgs.ac.uk/data_service/data/magnetic_indices/apindex.html
SWPC [NOAA] also compute preliminary real-time values. These computed values are truncated, so if, for instance, Ap = 9.99 it is reported [and plotted] as 9.00. SWPC is not very good at updating their graphs with definitive values, so one should not make too strong statements based on their graphs. The value for December, 2011 is a case in point. It is plotted as 2, but the real value is estimated [by BGS] to be 4.1.
The Aa index is based on one northern and one southern station, so does not suffer from some of the problems Ap has. The index can also be calculated from solar wind data: Aa = 1/6 BVo^2, where the solar wind magnetic field B is in nT and the solar wind speed Vo is in units of 100 km/s. Here is computed [blue and green curves] vs. observed [red curve] values since 2005: http://www.leif.org/research/Aa-Since-2005.png
You can see that geomagnetic activity is low, but not as low as at the end of 2009.
The reason for the low activity is that the solar wind speed is low [365 km/s]. This often happens near solar maximum.
UPDATE: David Archibald adds this graph and narrative –
Dr Svalgaard’s comment re solar wind and solar maximum might be misinterpreted to suggest that Ap Index is lowest at solar maximum. The opposite is true as shown by this graph from of the Ap Index from 1932.
The Ap Index is back below the floor established by all the previous solar minima. This is important, and there is a correlation between low Ap Index and cooling.
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Thanks to Don and others for inverting my thinking. Though naive, I still hope that CERN/Cloud can impact some of these postulates. Any comments on that thought would be appreciated – your posts are terrific.
Robert Brown says:
January 5, 2012 at 9:59 am
They tend not to emphasize the fact, but the 20th century was a Grand Maximum in solar activity
There is good evidence that there was no Grand Maximum in the last half of the 20th century:
http://www.leif.org/research/IAUS286-Mendoza-Svalgaard.pdf
http://www.leif.org/research/Effect-of-Weighting-on-SSN.pdf
@Robert Brown
> … the 20th century was a Grand Maximum in solar activity …
… which seems to be supported by the big peak in the fig 4-17 chart. But why is there no evidence of the MWP around 1000AD?
Is there any noise on this C14 signal which could cause a misinterpretation of these peaks and valleys?
John Day says:
January 5, 2012 at 9:42 am
………
There is no doubt in the short term there is high correlation between the heliosperic magnetic field and the cosmic rays (the regression has been calculated by many far more competent than myself), but in the long term the Earth’s MF fluctuations are far stronger. To the most of us, the link would be of a minor academic interest (excluding the space people) if it can be shown that there is no temperature link.
However, if there is a temperature link, than the temperatures since 1850 are affected to greater extent by the changes in the Earth’s field than by those of the inter-cycle oscillations.
John Day says:
January 5, 2012 at 10:54 am
But why is there no evidence of the MWP around 1000AD?
Why should there be? There is in fact [weak] evidence for a Grand Minimum, the Oort Minimum at that time.
Robert Brown says:January 5, 2012 at 9:59 am
……….
Hi Dr.Brown
I put up the graph on my website
http://www.vukcevic.talktalk.net/SSN-14C.gif
but I have strong reservation about the 14C and 10Be reconstructions.
Please don´t forget that every time Anthony has published a comment on the Ap Index, inmediately it happens what it has been called the “Watts effect”, a kind of sympathetic magic where the famous blogger actually affects Sun´s solar cycle almost instantly. Though we know that correlation does not mean causation, WUWT regulars wait with great expectancy this kind of posts, because they seem to reveal a kind of strange “sixth sense” of the popular blogger with the affairs occurring up above in the solar sphere, and immediately go to buy a lot of popcorn to attentively witness what will happen… even Dr.”S” and our friend Vuk buy theirs too, and wait…:-)
Look at the AP index in 2004 and see the 2009-10 El Nino, as well as the past decades temps reflecting on a 6.5 year lag.
http://img21.imageshack.us/img21/4577/yapper5.jpg
http://img811.imageshack.us/img811/2835/gggggggggggggggggggggge.png
Net decrease in AP relative to the Earth’s energy budget index leads to La Nina, upward spikes in the AP index lead to El Nino, 6.5 years down the road due to the thermal inertia of the ocean body. Change is driven through albedo and kinetic decoupling. When the sun reaches solar max we will begin a cooling trend. The Sun’s poles flip when the Sun hits max, the IMF goes north later this year, which when that happens it correlates to the dropoff in the AP index in 2005 on a 6.5 year lag, for some reason, which will be hit in ther lag time right when the IMF flips.
@Leif
> Why should there be?
If there were a strong positive link between solar ‘activity’ (sunspots/wind) and terrestrial climate such that increased activity implied higher temperatures, then you might argue (incorrectly perhaps) that higher historical temps implied increased historical solar activity. So in that sense, there “should be” a solar maximum to “explain” the MWP warming indicated by proxy records. Just saying.
Yes, I know, if pigs had wings they could fly.
😐
M.A.Vukcevic says:
January 5, 2012 at 11:29 am
but I have strong reservation about the 14C and 10Be reconstructions.
Those are not much in doubt [as far ad their general run is concerned, although some details are debatable]. What is really wrong is Usoskin’s reconstruction of the Sunspot Number. Compare several 14C and 10Be based reconstructions with his and see how he overblows the recent “Grand Maximum” which shouldn’t even exist: http://www.leif.org/research/Usoskin-14C-10Be-GSN.png
John Day says:
January 5, 2012 at 11:59 am
>” Why should there be?”
If there were a strong positive link between solar ‘activity’ (sunspots/wind) and terrestrial climate
But that is a circular argument. What the proxies show is that there isn’t a link.
Dr. Svalgaard, thanks for your explanations.
Don B says:
January 5, 2012 at 12:16 pm
Dr. Svalgaard, thanks for your explanations.
You are welcome.
@Phil says:
But this time, as for the extrapolations of M.Vukcevic, things will be different:
The polarity change this year and in the 2024 the Sun will fail to change its polarity. Though we are beginning to suspect that any “interesting” matters will have nothing to do with CO2 and all to do with changes in our GMF. (Vuk will remain silent on this though)
http://www.vukcevic.talktalk.net/LFC2.htm
Who says the sunspot # has to correlate to background TSI?
Thats what I suspect may be the case, the PDO and AMO both correlate to the Sun’s polar flips, PDO flips everytime the IMF flips south, AMO changes everytime it flips north, (PDO in 1999, AMO in 2012). I too think the answer lies in magentism operating through Albedo in the Earth system, so I don’t uderstand Leif’s asserting that because (if he’s right) that there was no grand Max or long term trend in TSI and sunspots, that the Sun’s effect on the climate is small. That is big jump because TSI and the Sunspot # have already been found irrelavent to climate.
It is more about the response in Earth system energies to relatively minor changes in the Sun, so there is no way to assert a “small” impact on climate, scientifically. The AP index clearly correlates to ENSO, and if minute variations in the AP index can force ENSO (albedo + the wind budget response to heat distribution) then thats all that anyone would need to know to take a stance.
Time will confirm Vukcevic’s predictions. If we can get a mechanism to explain the correlations, this may rank as another Milanković…
Phil says:
January 5, 2012 at 12:40 pm
Who says the sunspot # has to correlate to background TSI?
I do, except to variations of TSI above the unvarying background.
@Phil
> Who says the sunspot # has to correlate to background TSI?
@Leif
> I do, except to variations of TSI above the unvarying background.
Don’t get your hopes up, Phil. The total sunspot# variation is only 0.1% of the total TSI (1361 W/m² ), 70 times smaller than the change due to annual Sun-Earth distance variation.
http://www.leif.org/research/Eddy-Symp-Poster-2.pdf (slide #4)
(Leif, thanks for researching and disseminating this info to the world!)
That’s why TSI used to be called the “Solar Constant”.
steven mosher says:
January 4, 2012 at 3:43 pm
TB
That sounds like a climate model prediction.
predictions must be falsifiable in principle. numbers dude. add some numbers
Sure:
Forty-two, thirty-nine, fifty-six
(You could say she’s got it all)
All this clearly shows is we really don’t know and that we deinitely cannot do more than influence climate and our land use practices are probably more of a driver than a trace gas.
I do not believe the Sun’s irradiation is NOT the prime driver of climate in that it is the single biggest source of energy. I do not believe it doesnot vary over various time scales especially annually even if this is only an artifact of an elliptical orbit.
How do people go around making positive pronouncements like TSI varies by only 0.1% ?
And isn’t 0.1% slightly bigger than 0.04% ?
tallbloke says:
Sure:
Forty-two, thirty-nine, fifty-six
(You could say she’s got it all)
Plus the 250,000 per year.
“After-all it’s the sun that regulates the energy input of our planets climate and not the composition of atmospheric gases. :)”
incomplete. Fill the atmosphere with a gas that blocks incoming SW or outgoing longwave and you change the energy input.
ever try to shine a light through a cloud
ever try to sense an Ir emitter through C02?
John Day asked:
“So in that sense, there “should be” a solar maximum to “explain” the MWP warming indicated by proxy records. Just saying.”
As you requested:
“The warm climate overlaps with a time of high solar activity called the Medieval Maximum”
from here:
http://www.windows2universe.org/earth/climate/medieval_warm_period.html
but I don’t accept their use of the hockey stick or the assumption that recent decades have been warmer than the MWP.