Leif Svalgaard writes: “Several people asked why I said that the SWPC F10.7 graph was ‘just wrong’. And I promised a follow up on that. Here it is.”
Happy to oblige! For reference, here is the original graph from SWPC. – Anthony
The SWPC F10.7 Radio Flux Prediction Graph
Leif Svalgaard, May 2009
Fitting the monthly average the F10.7 flux (reduced to 1 AU) against the International Sunspot number, R, for the entire interval 1951-2009 to a forth order polynomial gives a formula for computing the Flux from the sunspot:
Flux = 67.29 + 0.316 R + 0.01084 R 2 – 0.006813 R 3 + 0.0000001314 R 4 (1)
The correlation is shown in Figure 1 below:
We know that this formula does not accurately portray the most recent relationship between R and F10.7 (see previous essay), but if we make no assumptions or corrections and just take the data as they are we can consider the conversion formula as indicative of the average conditions the last half century.
SWPC gives a table showing the predicted sunspot Number and the predicted F10.7 cm flux for the next decade. Here are the first few rows of that table, with the middle value of the predicted values in bold script, followed by a high and low limit:
Year Month Predicted Sunspot Number Predicted F10.7 cm Flux:
2009 01 2.1 5.1 0.0 67.4 69.4 65.4 2009 02 2.7 7.7 0.0 67.3 70.3 64.3 2009 03 3.3 8.3 0.0 67.2 71.2 63.2 2009 04 3.9 9.9 0.0 67.2 71.2 63.2 2009 05 4.6 11.6 0.0 67.3 72.3 62.3 2009 06 5.5 12.5 0.0 67.5 73.5 61.5 2009 07 6.7 14.7 0.0 67.8 74.8 60.8 2009 08 8.1 17.1 0.0 68.2 76.2 60.2 2009 09 9.7 18.7 0.7 68.8 76.8 60.8 2009 10 11.5 21.5 1.5 69.7 78.7 60.7 2009 11 12.6 22.6 2.6 70.2 79.2 61.2 2009 12 14.6 24.6 4.6 72.1 81.1 63.1
Using this table we can plot the predicted Flux as shown by the smooth red curve for the next solar cycle [or alt least up through 2015, Figure 2]:
I don’t know how SWPC came by their predicted F10.7, but my best guess is that they ran a correlation like the one shown in Figure 1 and applied it to the predicted sunspot number. Doing this using the observed sunspot number up to last month gives the ragged blue curve with the smooth blue curve coming from the predicted sunspot number. There is a good match for the predicted part of the curves [the red and the blue after May 2009]. The graph on SWPC’s website http://www.swpc.noaa.gov/SolarCycle/ seems to match the smooth curves quite well, with the exception of the variation during 2009, which I show as the purple curve. It is simply incorrect to start the curve from a flux of 60 and inexplicable [to my way of thinking – other than plain sloppiness] why the graph should disagree with the published table at http://www.swpc.noaa.gov/ftpdir/weekly/Predict.txt
As discussed in the previous essay and obvious from the discrepancy between the red and blue ragged curves above in Figure 2, the formula (1) for the average correlation between the Flux and the Sunspot Number does not work so well after about 1989, so it is not clear that it should work after May 2009. This means that we have little idea about what the predicted F10.7 flux should be. If the Sunspot Number prediction is correct, then the F10.7 flux is predicted too high, and if the F10.7 flux prediction is correct, then the predicted Sunspot Number is too high. My own feeling is that since the predicted Sunspot Number is really a prediction of the number of active [magnetic] regions which should be reflected in the F10.7 Flux, that the Sunspot Number [based on visible spots] will be much smaller than the predicted values. This will, indeed, be interesting to watch. Either way, we’ll learn a lot.
gotta ask: In “The Long Winter” by Laura Ingalls Wilder the old indian tells them that every seventh winter is a hard winter and the 3 hard winter (the 21st) is the hardest of all. Does this bit of folklore correlate with any solar or other cycles you guys chat about? (I’m a big fan of the Little House series — read them to 3 daughters…)
Is there any correlation between the radio flux and the solar wind?
That would be of high interest.
OT: http://www.nytimes.com/2009/05/18/science/earth/18juneau.html?_r=1
Sorry. But. Is the North American plate post glacial rebound being accounted for in the sea level rise accounting? Blaming it on current glacial melt rather than simply a continuation of the overall Holocene melts seems way off track to me. Not surprising, though.
Sorry to trash your thread Lief. I appreciate your contributions to this dialog.
More on topic: Several years ago, the Max Planck Institute posted a release stating that Solar Activity was at or above a 1,000 year high. Is that high now gone (as I assume), what did they mean, exactly, and do you agree with their statement?
Mark Hugoson (19:10:35) :
Is there any correlation between the radio flux and the solar wind?
There is [and there isn’t]. Solar activity itself [including F10.7] has a causative influence on the solar wind [that’s the is part], but not every little wiggle on the F10.7 graph has a corresponding solar wind wiggle [that is the isn’t part].
Carlos (19:22:00) :
More on topic: Several years ago, the Max Planck Institute posted a release stating that Solar Activity was at or above a 1,000 year high. Is that high now gone (as I assume), what did they mean, exactly, and do you agree with their statement?
Being above a 1,000 year high is hard, but I generally do not agree with that statement. See: http://www.leif.org/research/Napa%20Solar%20Cycle%2024.pdf or/and
http://www.leif.org/research/GC31B-0351-F2007.pdf
Leif: Thanks, again. It is so refreshing to read stuff from another genuine scientist who is out there trying to present the “best” info. available. Kudos, man!!!
Very nice, concise post, Leif. I take it then that you expect the sunspot numbers to be on the low end. Have you done any sort of a plot of how low the cycle 24 max will be relative to how long it takes to get started?
Oh btw, dad’s been following planting advice from some gardeners who are warmists, they all seem to have planted early this year. Problem is, tonite we are supposed to get a cold snap down to 20 F here in NH, which should kill off the warmists spring gardens nicely. But then again, thats weather, not climate….. rofl
Quaere
I know our main data on 10.7 goes back to 1947 but is there any organised regular data on this going further back? since I assume we should have been able to measure this for at least a decade before this.
Despite tantalising hints I have not been able to find any such records.
Kindest Regards
well …. Leif is Leif.
But I get the feeling that minimum flow is 60.
I lost something
Being above a 1,000 year high is hard
lol. That was a bit sloppy. 1,000 or more years, then.
I noticed that on page 4 of your second pdf, the “floor” seems to have much more variablity than your previous guest post indicates (where they were very much aligned). Is there any reason why, in your opinion, the floor 1000 years ago couldn’t have been even lower than it is currently, which seems now to be lower than the last two minima?
Mike Lorrey (20:06:57) :
Have you done any sort of a plot of how low the cycle 24 max will be relative to how long it takes to get started?
I think SC24 has started in earnest:
http://www.leif.org/research/TSI-SORCE-2008-now.png
a jones (20:15:01) :
I know our main data on 10.7 goes back to 1947 but is there any organised regular data on this going further back? since I assume we should have been able to measure this for at least a decade before this.
The radio emission was discovered during WWII but was secret until after the war, so there really isn’t any records.
Ventana (20:17:16) :
I noticed that on page 4 of your second pdf, the “floor” seems to have much more variablity than your previous guest post indicates (where they were very much aligned).
The ‘floor’ on page 4 pertains to the interplanetary magnetic field which is only peripherally related to F10.7. The floor in F10.7 cm [or the FUV flux] is shown on the Figure on page 7.
Is there any reason why, in your opinion, the floor 1000 years ago couldn’t have been even lower than it is currently, which seems now to be lower than the last two minima?
I assume you are now talking about the interplanetary magnetic field, B. Residual solar activity at the previous two minima kept that field a bit above the floor. At the current minimum solar activity has hit bottom as it last did in 1901 and 1913, and B is duly down to values that we infer for that time: http://www.leif.org/research/AGU%20Fall%202008%20SH24A-01.pdf
Since, you can’t less than no activity, we don’t think the floor can go much lower, but, in the end, that is speculative.
Leif,
MF is at its lowest variation, how would 24 have started if this component has not taken off yet? We’re not seeing any increase in sunspot activity either.
Also, from the second paper you posted a link to, you state that Earth’s magnetic field has decreased 10%. What impact does this have on the amount of TSI that reaches Earth’s surface?
Leif:
10.7 cm converts to about 2.8 GHz. I see on the frequency allocations chart that 2.69 to 2.7 GHz is allocated to Radio Astromomy, so maybe that is the actual frequency measured. The year of 1989 is within the time frame where the signal population in this portion of the radio spectrum began to expand greatly, including satellite borne transmitters. I wonder if the loss of correlation of the curves at the weak signal end could be due to an increase in the noise floor? The effect is certainly observable in other parts of the radio spectrum if you know what to look for, and might go unnoticed on a frequency where there are supposed to be no other signals. Also, why was that particular wavelength chosen in the first place? Is there a sun specific emission there, like the Hydrogen line near 610 MHz?
Mike Lorrey (20:51:42) :
MF is at its lowest variation, how would 24 have started if this component has not taken off yet? We’re not seeing any increase in sunspot activity either.
The solar Mean field [MF] basically measures the magnetic field strength of low-latitude coronal holes, and SC24 flux simply has not come down low enough yet for that to show up. We are seeing an increase in SC24 activity, even in the sunspot number [small as it has been – but that was the whole point of the previous essay, that perhaps there would be less visible spots]
Also, from the second paper you posted a link to, you state that Earth’s magnetic field has decreased 10%. What impact does this have on the amount of TSI that reaches Earth’s surface?
None
George M (20:53:56) :
I wonder if the loss of correlation of the curves at the weak signal end could be due to an increase in the noise floor?
If anything the noise [internal variation] has gone down. But the observers try to control and measure the noise, and AFAIK do not report any noticeable increase.
Also, why was that particular wavelength chosen in the first place? Is there a sun specific emission there, like the Hydrogen line near 610 MHz?
I think it has to do with availability of surplus radar equipment that Covington has to his disposal. Arthur Covington and his colleagues at the National Research Council in Ottawa used bits of military surplus radar and test equipment to make a radio telescope. The antenna was a 4ft (1.2m) paraboloid from a Type IIIC Gun Laying Radar, mounted on a prototype mount casting for a Model 268 radar. By leaning the mount so that the azimuth axis was pointed at the Pole Star, it was converted into a simple polar mount, which made tracking the Sun much easier. The receiver was a Dicke switching receiver used during the war to test silicon mixer crystals for radar applications. The radar system operated at a frequency of 2800MHz, which is a wavelength of 10.7cm.
The really fascinating thing about now is how the Penn and Livingstone prediction is shaping up as cycle 24 picks up. There are Sun spots, probably, but we can’t see them. Why? Is this what was happening during the Maunder? Does it affect climate? How? After seeing the extraordinary economic collapse occur exactly the way the people I was reading 4 or 5 years ago predicted, I now have the (intellectual) good fortune to see a significant moment in Solar Science play out. Lief, your contribution here and at solarcycle24.com is greatly appreciated. Thank you and may your most cherished theories be falsified. (It is good for you as a scientist and a person, not that many in the blogosphere would agree)
Mike Lorrey (20:51:42) :
Also, from the second paper you posted a link to, you state that Earth’s magnetic field has decreased 10%. What impact does this have on the amount of TSI that reaches Earth’s surface?
Although my answer was ‘none’, there are some that claim that cosmic rays influence the albedo [although observations show otherwise], and since the cosmic ray flux should go up with decreasing magnetic field, one could surmise that more clouds would form and temperatures therefore drop [although clouds also have a positive greenhouse effect]. Temperatures have generally increased since 1860, so perhaps this effect is not so strong. I think that ‘none’ still is a good answer.
partic (21:31:19) :
I now have the (intellectual) good fortune to see a significant moment in Solar Science play out.
Yes, times are exciting…
But let’s not forget that all this is still just speculation [however well founded].
Dr. Svalgaard,
It is a pleasure to read something that seems from another era, where rigorous precision of thought was valued. Such discipline as you’ve exhibited almost commands the reader (at least this reader) to think carefully upon the matter being read.
So, the assumption that was made in the new SWPC prediction is that the F10.7 & SSN will again agree as they did prior to 1989, even though there is no reason to assume this will happen.
Hey, if that magnetic region near the equator of the sun spits out a spot… what cycle will it be from?
well, IF something [ the sun ] did change around 1990, maybe the polynomial being used has to change to, it’s not the best fit anymore.
what would the coeffs look like for a 4th degree poly if it were generated by data starting in 1990 ? Why stop at a 4th degree ?
I have to go back and look at my numerical analysis book.
very interesting article, I also used your link and studied up on the hardware.
Mike Lorrey (20:11:10) :
I call that being distracted by alarmist reports, and failing to pay attention to what thier history tells them. While the connection between solar activity and climate/weather is messy business, there is plenty of historical record to show that crop problem years are more abundant in low solar activity phases, such as we have spent the last couple of years in.
It is a good idea in such times to plant 2 varieties: One warm and one cooler.
You can use shade cloth for cooler varieties when it’s too warm, but you need a greenhouse for warmer varieties when frosts hit late.
It’s the outliers which kill the crops.
If anything the noise [internal variation] has gone down. But the observers try to control and measure the noise, and AFAIK do not report any noticeable increase.
In other words, they are observing the background noise separately and calibrating it out. That would be good and sound scientific practice.
Although a science ignoramus I appreciate what little I understand of what I have read on this thread, but more than that I admire the calm, intelligent way in which the discussion has progressed. I look forward to reading more.
* “It is simply incorrect to start the curve from a flux of 60 and inexplicable [to my way of thinking – other than plain sloppiness] why the graph should disagree with the published table at http://www.swpc.noaa.gov/ftpdir/weekly/Predict.txt ”
Can we expect a correction of the SWPC Graph soon? It is indeed incomprehensible why the figure should disagree with their published table.
* On May 8 you wrote:
” from past relationships we know [if we use the correct ones] how much F10,7 to expect for a given SSN. The recommended [by the international Radio Communication people] formula is F10.7 = 63.7 + 0.728*SSN + 0.00089*SSN*SSN, that gives 65ish for the low numbers we have now and 136 for SSN=90.”
Is this formula the result of fitting the monthly average the F10.7 flux (reduced to 1 AU) against the International Sunspot number, R, for the interval 1989-2009? Or is it for the entire interval 1951-2009?
Thanks for clarification!
May be a dumb question – but how do we have 1000 year record of solar activity?