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.
“In my opinion temperature in the stratosphere as high as 10hPa is very much a function of ozone content as determined primarily by humidity.”
I am beginning to catch your drift. Significant mixing toward the poles lead to high humidity, ozone and humidity. I’ll have to ruminate further on this and maksimovich’s abstracts awaiting a muse.
David Archibald (20:49:23) :
Solar Cycle 23 is increasingly looking like Solar Cycle 4. It is a beautiful world.
And SC23 downramp is as fine a textbook example of a curve one could wish for. It is as if an artisan’s hand was at work.
Comparing SC4 downramp to SC23 downramp is like comparing Fred Flinstone’s work to Michealangelo’s.
Oh, sorry, getting off topic, but just can’t help thinking what the Creationists
would think when they get a load of that curve.
I do agree, David, that SC23 is a perfect to-scale fit for an SC4 restoration.
Project is on schedule for completion late 2009 to early 2010.
She’s a right-fine beauty, that SC23 is.
This current low gives us an opportunity to look at correlations and intimations of climate effects. I still think that the correlation of Maunder Minimum (no sunspots, high carbon-14 and berrylium-10, hence high GCR penetration) with the Little Ice Age (paleoclimate data from tree-rings, stalagmites, sediment patterns etc) showing lower temperatures – needs an explanation. Several factors may be at work: svensmark’s low level clouds or optical density effects reducing SW flux to the planet (ocean) surface; low UV affecting the polar vortex (Shindell’s work); possible electrical effects on aerosols/clouds/ice-crystals.
Camp and Tung have shown that there is an 11/22yr cycle effect on seasurface temperature that also has latitudinal components – and my feeling is the effect (at 0.2C) is too big to be due to TSI changes (0.1%) over the cycle – so we need an amplifier – and cloud effects are the chief candidate.
If we get a very low cycle it will be like a prolonged minimum. The effect of a short minimum may be small, but the longer it goes on, the effect accumulates. The oceans remix the signal with varying timelags. If we look at the jetstream patterns that are now current (with the low cycles effect on the polar vortex – and remembering from Shindell that there appeared to be a polar vortex effect in the Maunder Minimum), then we should be able to work out the dynamic. Right now there very large areas of the Pacific clear of cloud and absorbing SW in the southern hemisphere most strongly – currents will take this south to Antarctica – which should warm significantly (at last, and how happy for AGWers!). However, in the northern hemisphere, the clouds are shifting southward and exposing northern ‘warm pool’ waters to the night sky, as well as blocking sunlight absorbtion further south – hence the northern oceans will cool.
If we look at the last 30 years – 80% 0f ‘global warming’ is accumulated in the upper 200m of the oceans, but relatively concentrated in two large gyres in the north Pacific and north Atlantic. The first of these lost virtually all its heat by the autumn of 2006 – and there will be time-lagged knock-on effects downwind (Alaska cools first, then the Beaufort Sea, then eastward to the Norwegian Sea – with the summer ice starting to return in 2008). When the Atlantic gyre cools, and I expect this now to accelerate, western Europe will cool further. Right now western Europe is in the early stages of these cyclic effects – with shifts in the jetstream bringing torrential rain in summer, and polar highs in winter blocking the westerlies and bringing freezing conditions.
If this pattern continued under the solar minimum the northern hemisphere will cool by 0.5-1 C – but it looks to take a few decades to get that low. Obviously some places will be colder than others, and some warmer (e.g. central Siberia this last autumn).
The overall ‘global’ mean may not change much – because the southern hemisphere could get much warmer – but it also appears that ENSO amplitude was suppressed during the Maunder Minimum.
Meanwhile, in the upper atmosphere I note that 2007-2008 was warmer than the long term mean not cooler as was the surface (MSU data at 1km). Maybe this is the carbon dioxide effect!
What will be interesting if this minimum continues, is whether the CO2 and other greenhouse gases can counteract the surface/cloud/ocean dynamic significantly. In which case, we should invest in bumper stickers ‘carbon dioxide is my friend’! Well, at least until the upturn of the sun.
My own feeling is that CO2 can account for about 15-20% of the observed 1800-2005 global warming – the rest is recovery from the Little Ice Age (by whatever means – solar, clouds, ocean dynamic).
This minimum has a lot more time to keep going.
http://www.geocities.com/vukcevicu/14-23min.gif
shows N / S hemispheres monthly averages of the daily sunspot areas
(in units of millionths of a hemisphere)
http://www.vukcevic.co.uk/combined.gif
Leif Svalgaard (19:11:45) :
David Archibald (17:50:54) :
Do you know why they are hung up on a high amplitude instead of just letting the chips fall where they may?
My own theory [not official Panel policy] is this: Satellite operators usually borrow money to finance their operations [as most businesses do]. The lender requires that the hardware be insured. The insurance company needs to evaluate the risk of damage from solar activity. Having a risk figure, they then set a premium. They like the risk as high as possible to set the premium as high as possible. If the premium [the perceived risk] is too high [e.g. the solar cycle turned out to be very mild] the insurance company can be [and has been] sued. To be sue-proof, the insurance industry wants the Government to give them a number [preferably as high as possible], so that they can say: “hey, don’t sue us, we got the number from the Government”. How does that sound?
Leif,
This could mean that we have just experienced the first insurance fraud in Space when the Russian Kosmos 2251 crashed into Iridium 33 approximately 800 km over northern Siberia. I think the Russian Mob is behind it.
Solar Differential Rotation.
Some maybe aware I have been trying to track down if we are experiencing any change in the differential rotation rates of the Sun. Today I heard back from Dr. Rachel Howe from NOAE who specializes in this area, and she said:
” Thank you for your query. The solar differential rotation
does show slight changes during the solar cycle. There is not currently
a publicly available data product monitoring this, but there is an
extensive literature on the subject.
I attach a plot with the most recent results from MDI and GONG, shown
as a time-latitude false-color map of the difference between
the rotation rate and the temporal average, with the scale in nHz.
As it happens, my review article on “Solar Interior Rotation and its
Variation” has just been accepted by Living Reviews in Solar Physics and
a preprint version should be available on arXiv.org (astro-ph) this evening,
with figures including the most recent data. (The figures have been
degraded to save bandwidth, but the PDF version includes links to better
copies.) I hope this will be helpful.
Regards,
Rachel Howe”
While not exactly the information I am chasing none the less the up to date graphic showing the different rotation rates in the convection zone is quite fascinating.
http://users.beagle.com.au/geoffsharp/comb.png
We can see how currently the higher latitudes are experiencing slower than avg rotation rates while the equator is faster than avg but slowly decreasing as SC24 attempts to make a start, slower rotation = more activity. The Flow from SC23 is clearly ending around 2002 which lines up very nicely with the Solar Pole strength graphs from the WSO
http://wso.stanford.edu/gifs/Polar.gif
SC24 looks to begin its weak march way back in 1996 and certainly looks to be weaker than SC23. We can also see the start of SC25 and it also looks weak. Another paper by Frank Hill supports this.
http://www.ias.ac.in/jaa/marjun2008/JAA09.pdf
There is many different parts of the Sun showing different rotation speeds and this is just in the convection zone, what is happening beyond the Tachocline is another story, but perhaps we may gain something from this research that does suggest different rotation rates at times of grand minima.
It is easy to destroy a satellite if it is moving in the same direction; you just have to catch up with it. Real test of the space navigation expertise is to intercept one coming from the opposite direction. It is surprising that neither side is protesting too much.
Geoff Sharp (23:26:28) :
“I find it interesting how quickly Svalgaard jumps onto Archibald looking for the slightest crack and the manner and apparent venom in his replies is not exactly professional. That has all the hallmarks of a worried man. Archibald clearly stated in the beginning he was the first to predict a long cycle length for SC23 and did not deserve the “pissing” statement.
I also find it interesting that Svalgaard on most occasions backs up his arguments with his own research or papers. I would prefer to see more evidence from other sources to achieve some balance.
SC23 is very much like SC4 although the timing is slightly different….in the background the angular momentum is very similar on both occasions. Keep up the good work David, your method of thinking is refreshing”.
Geoff Sharp,
Do I sense a slightly jealous undertone here or do you really mean what you say?
I personally think we could not do any better.
I am sure we would not have this wonderful exchanges of knowledge and arguments if Leif wasn’t participating this blog with his postings, his patient explanations and his incredible amount of knowledge.
I do not mind him citing from his own papers at all.
If you can ‘t appreciate this I think you are missing the moments of opportunity here that makes this a really amazing blog.
What we see happening here is an almost real time confrontation of real serious “out of the box thinking” from David Archibald test benched by all the available knowledge available from Leif.
This is exactly how science works and how new ideas get hands and feet.
David presents his theory and projections in a brave cocky manner, short to the point and clear.
Leif starts challenging the fundamentals of this theory and pulls the arguments from his own database forcing David to come back and defend his claims.
In the mean time we are sitting in the front row seat.
I also have detected some rivalry (maybe irritation) between David and Leif but that is inevitable when creative characters interact. It comes with the package.
That’s how I think about it, no hart feelings.
Short remark:
We are not stalked by AGW proponents here.
This subject is not their cup of tea.
peter vd berg (02:29:40) :
To return to how little we know about the sun’s dynamics, the observed ‘cycles’ are to me like a trompe d’oeuil. Since we humans have brains which almost obsessively discern patterns and the infinitesimal lifespan of our species relative to the sun, we see patterns in it’s behavior as we see patterns in almost anything but which have little or no relation to the actual facts. Look at it another way you see another pattern. The well known cartoon of Freud which can look like a nude female form springs to mind.
Should our lifespan reach anything like more then a mere second of the sun’s lifespan we might be able to determine the real pattern. But it will be some time before we live to be a 100.000. Till then solar prediction is just an amusing brainteaser, fun to do but pretty much useless
Peter,
And you are an optimist?
Geoff Sharp (15:15:22) :
SC24 looks to begin its weak march way back in 1996 and certainly looks to be weaker than SC23. We can also see the start of SC25 and it also looks weak. Another paper by Frank Hill supports this.
You might be off by a cycle…
Peter Taylor (10:13:06) :
This current low gives us an opportunity to look at correlations and intimations of climate effects.
Pete,
Thanks for the superb, balanced summary of our current circumstance.
-psi
Ron de Haan (15:49:29) :
I certainly wouldnt like to see Leif depart this fine Blog, he certainly keeps us in line….but that was not my point.
The issue or ionospheric refraction/reflection mostly effects only low frequency bands. I doubt it will have any effect on digital TV reception.
It can be very strong in the commercial short wave band, CB frequencies, and 11meter amateur radio bands. Once you get to a radio frequency above the MUF (maximum usable frequency) the ionosphere becomes transparent to radio signals — at least it bends them a negligible amount.
The traditional TV bands are in the VHF and UHF frequencies, which are for the most part line of sight frequencies and usually well above the MUF although radio amateurs can occasionally use skip in unusual conditions at VHF frequencies it is not common.
By line of sight I mean they have limited ability to go over the horizon or reflect off the ionosphere, so sun spots and ionospheric effects have essentially no effects in those frequency bands.
For example I used to live in the radio shadow of North table mountain (on the west side of Denver metro area), having no line of sight to Lookout mountain (the location of the major radio/tv towers). I could get good pictures in the 2-6 channel range on analog TV, but reception started to get shaky at the higher channels.
As you can see below, when you go to channel 7 and 9 in our local area you jump from the high 80 Mhz range into the 170-180 Mhz range, those channels are much more prone to “radio frequency shadow” due to obstructions, but they also tend to bounce better off of obstructions so you get weaker primary signals in a shadow area, and more ghost images from secondary reflections. As you go even higher in frequency the radio signals behave more and more like light does, becoming very directional, giving strong shadows behind obstructions.
VHF TELEVISION FREQUENCIES
BAND CH # FREQUENCY
VHF LOW 02 54-60 Mhz
VHF LOW 03 60-66 Mhz
VHF LOW 04 66-72 Mhz
VHF LOW 05 76-82 Mhz
VHF LOW 06 82-88 Mhz
VHF HIGH 07 174-180 Mhz
VHF HIGH 08 180-186 Mhz
VHF HIGH 09 186-192 Mhz
VHF HIGH 10 192-198 Mhz
VHF HIGH 11 198-204 Mhz
VHF HIGH 12 204-210 Mhz
VHF HIGH 13 210-216 Mhz
By the time you get to channel 31 you are in the UHF band at 572-578 Mhz. In my location it took divine intervention or small animal sacrifices to get even crappy reception. During the digital conversion many of these lower frequencies will be abandoned for TV use as they cut over to the new digital frequencies and re-assigned them to other applications.
http://en.wikipedia.org/wiki/North_American_broadcast_television_frequencies
Bottom line, is the new digital channels will behave differently than the old analog channels due to both shifts in frequency and the change over to digital.
On the old analog signals you could (if you had any signal at all) at least get the audio of the broadcast or a snowy video plus audio. With digital you have a win some lose some situation, where if you get a signal, it will usually be bright and clear or no picture at all. It will be pretty much an all or nothing reception. The blocking you talk about, will show up in that small band where sometimes the receiver gets enough info to process the digital signal and sometimes it does not.
So to answer you primary questions:
1. Is a stronger digital signal any more likely to be a clearer signal?
If you get a good signal it will be a nice clear picture, if you drop into marginal signal strength you will probably get no usable TV image. (you might want to look at the amplified digital antennas if this is still an issue after the cut over).
2. Do digital or analog t.v. broadcasts make use of the “skip” which you describe as so usefull to radio broadcasts?
No! The ionospheric skip is most effective in the lower frequency bands. The ionosphere is essentially transparent to radio signals from the UHF band up to microwave. In that sense, solar activity will have little if any direct effect on digital signals, although its effect on the extended upper atmosphere may cause problems for low flying communications satellites due to increased atmospheric drag. Major solar storms will threaten satellites at all altitudes but that problem is typically a problem during periods of high solar activity not low solar activity.
3. If we are not in “line of sight” of the broadcast antenna, will we still be receiving a signal?
It will be more of an issue, and no general answer can be given. Radio frequency shadow effects will be stronger at the high frequencies used in the new digital channels but it is hard to say how increased broadcast power will effect that in your particular case. You might contact the engineering department of the station you are concerned about, they should be able to give you a good guess based on their engineering studies, and help you determine if you will have good reception. Some of them will fill coverage gaps on alternate translator frequencies so you might be able to get the signal by switching to a different frequency than you normally would for that channel.
At my old location, I could get channel 20 by aiming my TV antenna at a near by mountain and picking up a reflection off the peak that was stronger than the direct signal, but at that house I never could figure out a way to get channel 31 until I went to a satellite service. By using Direct TV I could get all the channels as part of their package, and those signals will all be digital.
Larry
bill p (23:57:09) :
Bill:
Drop me an email at w5vpqarrl.net. I’ll be happy to explain the apparent silliness about the DTV conversion.
Sry, forgot the tag thingies. Put the at sign between the q and the a.
Leif Svalgaard (17:12:55) :
You might be off by a cycle…
Do you think, I guess this sort of diagram can be interpreted differently and also the time frame is short. I see it as the equator having the impact with SC23 tapering off around 2002, with each cycle having its roots way back that forms a V shape gradually building in strength and begins to take over when the preceding cycle ends. I know the actual SC23 solar cycle began around 1996 but perhaps SC24 was also starting in its infancy?
Another observation on the differential rotation diagram, SC23’s Rmax coincides right on with the slowest rotation speed at the equator.
http://users.beagle.com.au/geoffsharp/comb.png
I think this would be an invaluable tool if we could access it easily like the WSO polar strength graph and watch each move through the cycle. I informed Dr. Howe of this, lets hope it gets something going.
Geoff Sharp (19:08:34) :
>i>”You might be off by a cycle…”
Do you think, I guess this sort of diagram can be interpreted differently
No, SC23 started in 1994, built from the polar fields that started to build up in 1991, after their reversal in 1989, SC24 started in 2005, built from the polar fields that started to build up in 2003, after their reversal in 2000, and SC25 will not start until after the polar fields reverse sometime after 2014-2015 and begin to build up again. If you think differently then you must qualify your statements appropriately. “We can also see the start of SC25” is not qualified as it should be.
Geoff Sharp (19:08:34) :
”You might be off by a cycle…”
Do you think, I guess this sort of diagram can be interpreted differently
No, SC23 started in 1994, built from the polar fields that started to build up in 1991, after their reversal in 1989, SC24 started in 2005, built from the polar fields that started to build up in 2003, after their reversal in 2000, and SC25 will not start until after the polar fields reverse sometime after 2014-2015 and begin to build up again. If you think differently then you must qualify your statements appropriately. “We can also see the start of SC25″ is not qualified as it should be.
And yet more…you can see in the pattern why early cycle sunspots appear at high latitudes then gravitate to the equator, thats what the dark blue areas are, the poles “earthing out” on the sunspot that is created in the area of slowest rotation.
This might be a new kind of Hale cycle that begins before the change in polar polarity and the overlapping preceding cycle causes the polarity change. We might have the workings to explain the 11 year solar cycle…its all driven by the V patterns driven by differential rotation. Now we just have to work out why the differential rotation changes.
Geoff Sharp (19:41:23) :
We might have the workings to explain the 11 year solar cycle…its all driven by the V patterns driven by differential rotation.
Take heart from the fact that scores of solar physicists are working on that very problem [and have been for a long time].
Leif Svalgaard (19:35:04) :
If you think differently then you must qualify your statements appropriately. “We can also see the start of SC25″ is not qualified as it should be.
This is not easy when discussing a diagram like this….but here is one I prepared earlier that has purple arrows showing the beginning of the flow….that is the start of the V which is connected to 2 cycles.
Also the latitude changes (dark blue area’s) correspond with where the cycle spots appear…the latitudes look correct?
http://users.beagle.com.au/geoffsharp/comb.jpg
I agree regarding Leif’s explanation of TSI, magnetic field variations, solar wind, etc. There is much that is known about the Sun, thanks to Leif’s explanations. Especially those related to heat. These parameters can be mathematically represented, like a Bunsen burner in an experiment, and thus have a known variable that represents them, like the dials on my stove top. Were these sources of potential heat increases (and by logical conclusion, decreases) actually the dials on my stove, I could turn them from dead off (no spots) to all the way up to high (sunspot-marked like a teenager’s acne) and not tell with my hand pressed on the burners whether or not there was a difference in heat. Interestingly, his patient explanation of the extremely small variations in the Sun, which results in an extremely small variation in Earth’s lower atmospheric temperature, is much like CO2. CO2’s affects are as small as the Sun’s. In my humble opinion, warmers should be protesting against the oceans.
Geoff Sharp (20:11:03) :
This is not easy when discussing a diagram like this
Just take what I say at face value, then it is easy. SC23 began in 1994 off the left edge, and SC24 in 2003 or 2004, about where you have the arrows. Sunspots tend to form at the boundary between purple and yellow; where the shear [velocity difference] is the largest. I have tried to explain this several times before. Here is a plot of the velocity from Mt. Wilson: http://www.leif.org/research/Torsional%20Oscillation.pdf