I had written back in July 2008 about the 10.7cm solar radio flux hitting a new record low value. Part of that has to do with the inverse square law and the distance of the earth to the sun, which is at a maximum at the summer solstice. As you can see below there has been a very gradual rise since then as we approached the winter solstice. David Archibald provides an update below and compares our current period to other solar cycles. – Anthony
UPDATE: In comments, Leif Svalgaard offers his graph, and also speaks of the flatlining. See below the “read more” – Anthony
The graph above is of two year windows of the F 10.7 radio flux centered on the last five solar minima. They are stacked up so that they are 20 solar flux units apart on the same vertical scale. The original data is from: http://www.ngdc.noaa.gov/stp/SOLAR/ftpsolarradio.html#qbsa
That site notes:
“The quiet sun level is the flux density which would be observed in the absence of activity. Extrapolation to zero of plots of the 10.7cm flux against other activity indices such as plage area or total photospheric magnetic flux in active regions suggest a quiet sun flux density of about 64 s.f.u. This is rarely attained.” The lowest daily value in this minimum to date was 64.5 in June 2008.
What is evident is that this minimum is quite different from the previous four in that the intra-monthly amplitude has died from June 2008. The monthly average low was July 2008 and the series has been in uptrend at 0.7 units/month thereafter. This is a very weak but very consistent uptrend, perhaps the first sign of a rising Solar Cycle 24. There is very little noise in this signal, suggesting a very weak Solar Cycle 24.
– David Archibald
UPDATE: Leif Svalgaard writes in comments:
As part of my ‘homework’ for the Sunspot Panel [2 years ago] I produced a short document
http://www.leif.org/research/When%20is%20Minimum.pdf
comparing F10.7 and MgII [another solar index] around minima. I have updated the graph in the document to show the flat-lining of F10.7.
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the_Butcher (08:39:01) :
And how much time it takes to reach Earth?
Leif gave you the 10.7MHz flight time.
The other flux, that of the solar wind, is currently (from spaceweather.com) about 320 miles/S. At 98 million miles to the Sun, the distance is covered by the solar wind in 85 hours, which is fortunate as it gives us warning of a big hit from a coronal discharge.
Leif,
Is the “flatlining” of the solar flux related/correlated with what’s happening with the cr flux? As you know, this minima is supposed to correlate with a “pointed” peak in cr flux. And we’ve been bouncing around the top for so long now that we basically have a “flatlined” peak. I don’t think there is any way to say, for sure, what the shape of this peak will be until we get well down the backside of this cr flux cycle, it looks like it could turn out to be flatter than I would have expected for an odd-even transition.
Basil
The Total Solar Irradiance data for Sorce looks like is is idling/flatlining as well.
http://lasp.colorado.edu/cgi-bin/ion-p?ION__E1=PLOT%3Aplot_tsi_data.ion&ION__E2=PRINT%3Aprint_tsi_data.ion&ION__E3=BOTH%3Aplot_and_print_tsi_data.ion&START_DATE=1640&STOP_DATE=2400&TIME_SPAN=24&PLOT=Plot+Data
Leif, When the Sun is idling for this long, isn’t this a possibly once in a lifetime opportunity to see how it works? When everything is on the spin cycle, you can’t tell what the clothes are in the machine. But when it is simply draining itself of the water, you can now see the clothes. Seeing it’s mechanisms at work on idle speed just seem to me to be the perfect time to figure out how it works. What are some of the Sun’s curiosities, unknowns, and parts of the mathematical calculations that are still iffy that have the potential of being solved while the Sun is just sitting there (in a manner of speaking)?
hotrod (10:32:14) :
Is there a theoretical “floor” for the 10.7 cm emission?
Yes, about 64 solar flux units, corresponding to the ‘quiet’ Sun without sunspots and active regions.
From a quick look at other sources, it looks like 10.7 emissions effect the virtual height of the F layer of the ionosphere, and electron density in the ionosphere, and serves as an “objective” measuring stick for general solar activity and magnetic complexity, without the subjective issues counting sunspots and computing sunspot numbers involve.
10.7 does not affect anything but is a good [better than spots] proxy for things that do affect the ionosphere.
that association simply implied by the correlation between sunspot numbers and irradiance, and the correspondence between 10.7 emissions and sunspot numbers ?
implied
To rephrase that, if you have a 10.7 emission number can you with any confidence predict the total solar irradiance at the top of the atmosphere ?
short answer is ‘yes’.
IBM did a study of cosmic ray flux v. sunspots.
http://www.research.ibm.com/journal/rd/421/ziegl4.gif
Sorry, I meant to point to the paper itself.
http://www.research.ibm.com/journal/rd/421/ziegler.html
Robert Wood (10:38:50) :
The other flux, that of the solar wind, is currently (from spaceweather.com) about 320 miles/S.
There is a third flux which may be even more important: that of solar energetic [deadly] particles which may reach us in a few hours after we see an explosion on the Sun.
Basil (10:40:46) :
this minima is supposed to correlate with a “pointed” peak in cr flux. And we’ve been bouncing around the top for so long now that we basically have a “flatlined” peak.
The main reason we see a ‘pointed’ peak is that the other transitions have been short. With a drawn-out transition you get [as we have now] a drawn-out peak. There is a systematic difference in height of the ‘peak’ between E-O and O-E [as we have now] transitions having to do with how the charged GCRs drift in unipolar magnetic fields [over the poles of the Sun]. If this minimum dragged on for another 5 years, the ‘peak’ would be flat for those years. The cosmic ray flux lags about 6 months after solar activity, so with a minimum in, say August-September, 2008, we should begin to see the GCR flux decrease about now.
Basil (10:40:46) :
this minima is supposed to correlate with a “pointed” peak in cr flux. And we’ve been bouncing around the top for so long now that we basically have a “flatlined” peak.
The main reason we see a ‘pointed’ peak is that the other transitions have been short. With a drawn-out transition you get [as we have now] a drawn-out peak. There is a systematic difference in height of the ‘peak’ between E-O and O-E [as we have now] transitions having to do with how the charged GCRs drift in unipolar magnetic fields [over the poles of the Sun]. If this minimum dragged on for another 5 years, the ‘peak’ would be flat for those years. The cosmic ray flux lags about 6 months after solar activity, so with a minimum in, say August-September, 2008, we should begin to see the GCR flux decrease about now.
kuhnkat (10:15:25) :
could we use IDLING instead of FLATLINED???
I compliment you on such an excellent choice of wording.
Idling as opposed to flatlining or even lack of amplitude, brilliant.
I made a mention of part of this before. Since we have never really observed a Sun at IDLE for a full year before (that I have seen any representation of), the inference of AU distance effect on the baseline F10.7 is reasonable, but not tested.
Ramping and deramping have gotten in the way of a clean read, and I
strongly suspect the possibility of high/low of F10.7 baseline does not match up with Perihelion/Apphelion.
For lack of any other reads as clean as the latter half of 2008 onwards,
a steady ramp is currently indicated, but not assured.
Pamela Gray (10:46:42) :
When the Sun is idling for this long, isn’t this a possibly once in a lifetime opportunity to see how it works?
Yes, solar physicists are all very excited about this.
What are some of the Sun’s curiosities, unknowns, and parts of the mathematical calculations that are still iffy
As per Rumsfeld, there are also the unknown unknowns and those are perhaps the most exciting. But to mention a few of the known unknowns:
1) the depth of the dynamo [low or high cycle 24]
2) mapping of plasma flows in the Sun’s interior
3) what is a sunspot? [yes, we don’t know!]
4) what causes a CME [and flares] and can a CME be predicted
5) why is the corona so hot
6) why does the heliospheric magnetic field vary a lot less that the Sun’s magnetic field
Pamela Gray (10:46:42) :
When the Sun is idling for this long, isn’t this a possibly once in a lifetime opportunity to see how it works?
Yes, solar physicists are all very excited about this.
What are some of the Sun’s curiosities, unknowns, and parts of the mathematical calculations that are still iffy
As per Rumsfeld, there are also the unknown unknowns and those are perhaps the most exciting. But to mention a few of the known unknowns:
1) the depth of the dynamo [low or high cycle 24]
2) mapping of plasma flows in the Sun’s interior
3) what is a sunspot? [yes, we don’t know!]
4) what causes a CME [and flares] and can a CME be predicted
5) why is the corona so hot
6) why does the heliospheric magnetic field vary a lot less that the Sun’s magnetic field
7) any many more
For all we know about the Sun, F10.7 baseline could have it’s own inherent cycle, independent of AU distance, and we would need a full-blown Maunder to resolve it.
Leif Svalgaard (11:09:45) :
The cosmic ray flux lags about 6 months after solar activity, so with a minimum in, say August-September, 2008, we should begin to see the GCR flux decrease about now.
Don’t you mean, “for a minimum in Aug – Sep, 2008, we should see the GCR flux plateau about now”?
“Leif Svalgaard (09:29:38) : ….Several solar physicists have predicted [several years ago] that cycle 24 would be the smallest solar cycle in a hundred years.”
Could I have links/ names of all these? I’d like to read up on what they said.
I am curious to know if anyone has ever done a study to try and determine which way the Sun ‘walks’ in spectrum when in Maximum and in Minimum.
The walk would be from G2V up to say, GO, or down towards a lower state of say, G5, in the main sequence.
The YouTube video at this link shows some of the study being done in the area of Space Weather/ cosmoclimatology/ sun/ cosmic particles/ clouds :
YouTube title :
Space weather and climate change
link :
Robert Bateman (11:26:16) :
For all we know about the Sun, F10.7 baseline could have it’s own inherent cycle, independent of AU distance, and we would need a full-blown Maunder to resolve it.
but is does, as nobody studying the Sun looks at the observed F10.7 [which, however, is the all important parameter for terrestrial effects]. The ‘for all we know’ should perhaps be interpreted as ‘for all you know’. There is good evidence that the Sun was not any dimmer [F10.7, TSI, or otherwise] during the Maunder Minimum than it is right now. E.g. see http://www.climateaudit.org/?p=2470 ‘line 2’
It may take a full-blown Maunder Minimum to take this issue of the table for some folks, although I’ll predict that there will still be some that will say, that ‘for all we know’ there could be an even bigger [or deeper] minimum lurking somewhere. There will always be such people.
The Raspopov paper (or as much of it as i’ve read) raises my Spockian eyebrow early on:
“An appreciable delay in the climate response to the solar signal can occur (up to 150 years). In addition, the sign of the climate response can differ from the solar signal sign…”
Can occur? Up to? Can differ? Sounds highly iffy. I bristle at bristlecone pines, and I shudder at periodicity association diagrams. no matter what the r, especially when prefaced by statements like: “delay…can occur”. Maybe I’ll read the rest of it later.
‘Ninety-three percent of all murders occur within a week of a new or full moon.’–Luz Cañon, Statistician
Richard deSousa (10:31:11) : wrote:
We’re all travelers along for the ride as the sun does it’s “thing”… let’s hope it’s “thing” isn’t going to be catastrophic for us travelers. I can’t imagine what the hundreds of millions of people in the northern hemisphere are going to do if we’re coming upon the beginning of a little ice age… or worse. 🙁
—————————-
Yes, especially as AGW alarmism has pretty much taught us, by focusing our thoughts and observations, that we will not be able to stop it by pumping carbon dioxide into the atmosphere.
Meanwhile:
Hundreds attend protest against global warming:
http://img255.imageshack.us/img255/7131/100sattendgwprotestnt1.jpg
Leif Svalgaard (09:20:31) :
As part of my ‘homework’ for the Sunspot Panel [2 years ago] I produced a short document http://www.leif.org/research/When%20is%20Minimum.pdf comparing F10.7 and MgII [another solar index] around minima. I have updated the graph in the document to show the flat-lining of F10.7.
Leif,
Nice work on “When is minimum?”, it is a very interesting question. But I have to question the logic in your PDF: You state that you are averaging minima 1947-1999 and comparing the declining SC23 with that. That means your entire set of reference cycles comes from the SC16-22 group of cycles, which is just a subset of the observed cycles, and I would say a biased subset. To illustrate this point, look at this graph
http://users.telenet.be/j.janssens/Spotless/Spotless.html#Evolution
We have at least two series of cycles that behave very differently around minimum, i.e. cycles 10-15 and 16-22. We can also see that SC23 if anything is much more similar to cycles 10-15 than the ones you have used.
So my suggestion would be to redo your computation using average cycles 10-15 data instead and see what that does to the estimate of the minimum for SC23. I suspect it results in a significant delay of minimum.
This of course depends on availability of sufficient quality data for those old cycles. If it does not exist I think the minimum is anyone’s guess (I have my own).
Leif Svalgaard (11:22:26) :
3) what is a sunspot? [yes, we don’t know!]
I learnt some time ago, looking onto a sunspot would be the equivalent of looking onto a cross section of a MHD flux tube?
“Hundreds attend protest against global warming:” OT!!! but funny.
Someone had too much time on their hands.
Would some one please explain this in lay man terms, so that we who are lacking in scientific knowledge can understand this? does this mean we are headed for colder weather for a significant amount of time? how long maybe? please explain so I can understand.
I hope this will be considered OT. It IS about the sun, sort of. It is the beginning of a scifi story published in 1946, written by an astronomer named Robert S. Richardson, who wrote under the pen name Philip Latham.
Here is the first page of the story. Reading the first few paragraphs was almost like reading wuwt.
The name of the story is: N Day.
I have it in an anthology entitled A Treasury of Science Fiction, edited by Groff Conklin
==================
Tuesday, 1949 January 18
Sunspot maximum and three days without a single spot!
This cycle is certainly developing in a peculiar way. From the last
minimum about March, 1944, sunspot activity jumped to a Wolf Number
of 252 in December, 1948, the highest index on record since that
rather dubious maximum back in 1778. But this month spots have
simply failed to appear, as completely as if someone inside the sun
had pulled a switch.
Clarke’s elaborate empirical analysis has failed utterly to
predict. I am now more firmly convinced than ever that no
combination of harmonics can ever represent the approximate
eleven-year rise and fall in the number of sunspots.
Instead I favor Halm’s old idea that each cycle is a separate
outburst in itself. The very fact that our star is a weak variable
means it is to a certain degree unstable. Not unstable to the
extent of a Cepheid variable but still�unstable. Indeed, Halm’s
hypothesis appeals to me more strongly now than when he announced
it four cycles ago.
There I go measuring my life in sunspot cycles again! But four
cycles does sound much less than forty-four years. Yet how little
more I know about the sun than when I first came to Western Tech.
In many ways the sun reminds me of a woman: just when you think you
are beginning to understand her, invariably she will fool you.
Enough of that. What business does an old bachelor have writing
such things in his diary?
The driving clock on the coelostat was out of commission again
today but I will have to repair it somehow. President Bixby refused
my request for three hundred seventy-five dollars on the grounds
that the…..
Copyright, 1946, by Street & Smith Publications, Inc. Published in
Astounding Science-Fiction. Reprinted by permission of the author.