Leif Svalgaard writes in with a collection of points on the 10.7 cm solar radio flux. Being busy tonight, I’m happy to oblige posting them. – Anthony
Leif writes:
People often call out that F10.7 flux has now reached a new low, and that a Grand minimum is imminent.
Perhaps this graph would calm nerves a bit:
The blue curve is the current F10.7 flux [adjusted to 1 AU, of course] and the red curve is F10.7 back at the 1954 minimum. The D spike (in 1954) was due to an old cycle [18] region.
There is always the problem of how to align two such curves.. These two were aligned by eye to convey the general nature of the flux over a minimum. The peaks labeled B and C and the low part A were arbitrarily aligned, because peaks often influence the flux for several weeks so would form natural points of correspondence. The detailed similarity is, of course, of no significance. Note, however that because of the 27-day recurrence one some peaks are aligned others will be too. again, this has no further [deeper] significance. The next solar cycle is predicted to be quite low and the cycle following the 1954 minimum was one of the largest recorded. We will, of course, with excitement watch how the blue curve will fare over the next year or so, to see how the ‘ramp up’ will compare to the steep ramp up in 1955-1956.
Of course, as there was more activity before and after the minimum and even during [as cycles overlap]. For the very year of the minimum apart from the spike at D there is very little difference. The important issue [for me] is the absolute level, because that is a measure of the density and temperature of the lower corona, generated by the ‘network’ or background magnetic field, which seems very constant from minimum to minimum, and certainly does not portend an imminent Grand Minimum, which is not to say that such could not come, just that a low F10.7 is not an indicator for it.
I’m not a defender of Dr. Svalgaard by any means, but I think his point is simply that the red and the blue lines bottom out at the same level on the graph, which means the solar minimum is the same intensity or lack there of, it says nothing about duration…
In defence of Leif (not that he needs any help from me to defend him, of course) I think the only point he was trying to make was that F10.7 is not a good indicator of what might happen next… and that’s all folks!
The blue curve appears to have a higher SNR versus the red one.
Nerves all calmed. 🙂
I am surprised that Dr. Svalgaard has resorted to ‘wriggle matching’. SC20 an SC23 for 8 years out of 11 are closely matched (some time exactly month after month), even correlation is nearly 90%, as this chart shows (axis has scale in months)
http://www.geocities.com/vukcevicu/SC20-23.gif
‘Wriggle matching is not science’ I was told on numerous occasions!
The 1954 to cycle 24 overlay is a bit too arbitrary for my liking. I think it would be better to see a two cycle (23-24) F10.7 plot then compare it to another, similar, cycle. There are obvious indications that cycle 24 is beginning to ramp up. the question is how much and when it will peak. As a frustrated radio amateur I have a great deal of interest in the upcoming cycle.
Retired Engineer (07:06:22) :
And I am not sure how well our measurements in 1954 would match what we can see today. Instrumentation was not nearly as sophisticated 55 years ago.
For this purpose they were. Considerable effort has gone into calibrating the early data onto an absolute scale [that is directly in Watt], see: http://www.leif.org/research/Tanaka-Calibration-F107.pdf Different observatories operating for a long time have their own relative scale which is much more accurate than the early absolute values, but by careful cross-comparisons between observatories one can construct a consistent series. An earlier post a few weeks ago http://wattsupwiththat.com/2009/05/14/the-solar-radio-microwave-flux/ has more on this, and also shows another version of the 1954:2008 comparison [with no wiggle matching]
Jim, Tony b,
Try “Global contrail radiative forcing and the impact of diurnal variations of air
traffic” by N. Stuber and P. Forster (ACPD 6, 9123–9149, 2006).
They conclude that the contribution of contrails is between 10% and 30% of the claimed CO2 effect of air transport; reading their report my conclusion is that is is closer to 10%, as the upper boundary seems to be have been derived from other studies. They find a much smaller effect than earlier studies, because they recognised that the IR reflection of contrails would only have a net effect during nighttime (and clear sky) while 2/3rds of air traffic is during daylight.
There is a suspicion that contrails may trigger the forming of cirrus clouds, but this seems to be very uncertain.
Evert
Dennis Sharp at (8:03:11)
Ask you boys at NASA about the Maunder Minimum and the little Ice age. Explain what caused it if it wasn’t the Sun it was moon beam reduction.
Lief,
Your humility and that you protesteth much that 10.7 is not a good predictor, makes one wonder why you presented this comparison graph. Looking at the graph, one is seduced into believing that cycle 24 is on the threshold of bursting forth. In earlier posts (I apologize for not chasing down the links so I can stand correction) I recall you stating that it had already begun and that rising “activity” of a non-sunspot variety was already heralding the new cycle. Could it be that this illustration is a forecast that you can disown – “after all, I did say that 10.7 was not a predictor.”
After reading vukcevic’s comment:
vukcevic (04:46:06) :
Dr. Svalgaard
When I mach my polar fields equation
http://www.geocities.com/vukcevicu/PolarField1.gif
to the actual measurements for a period extending to 30 years, you kindly describe it as ‘GARBAGE’.
May I return compliment in regards to the chart above.
and looking at his graph, I’m not sure of your humility. Actually, vukcevic’s equation certainly looks good so far, as good as anything else put forward on the subject.
I look forward to the collapse of scientific egos that is certain to come over the next years and decades and a return to the good old days of scientific humility (usually courtesy goes along with it) that has been ravaged by the political-scientific industrial complex that has engulfed us over the last decade. My forecast is that we are entering an era where we can learn a lot about the sun-earth couplings. I’m sure we will resist it much and hang on tighter to our egos until we are forced to let go.
“wiggle matching” to while away the wait. I like.
As put Milton, “those also serve, who merely watch and wait”.
Regarding the aircraft contrails, I remember that during the month or so with no airplane flights after 9/11/01, the temperatures were cooler than expected by some small amount. The thing I thought at the time was, hey, maybe the contrails are enough to make a difference, even though they seem not so big, because there are so many of them. (Of course, I only think that the temps were lower because somebody–on the news?–said so. And it was more of a “how about that?” moment than an “odd, wonder why that is?” thing.)
I think that Dr. Svalgaard’s point might be summarized as “when you’ve been ’29-y.o.’ for a while, you recognize that not every change is UNPRECEDENTED!!! and maybe we shouldn’t be getting our panties in such a twist about every thing we see.” Thus leaving watch-and-wait as the preferred strategy for many of these things, allowing them to resolve and come into better focus before getting excited.
Since I’ve been stuck on 29 for a little while now, I agree with him! 😉
Very interesting, Leif. As always, a work of quality and honest, besides.
Sorry for my insistence, but from this analysis by Leif Svalgaard I am compelled to insist on not putting too much confidence on an imminent ice age. It seems the Earth is going through a warmhouse, not an icehouse. From Leif’s collage we can infer that the F10.7 cycle will be retrieving power by the middle of 2010. Even when uncertainties are present, the probability on the current low solar activity could not be part of a grand minimum is high. Consequently, we could expect the enhancement of the solar power in the next months and increasing of the fluctuations of the surface temperatures with it.
Has anyone wondered about why it is that solar cycles vary in length? And whether it’s a portent of what will happen in succeeding cycles?
Gary P: You can get detailed analysis of cloud cover from the International Satellite Cloud Climatology Project (ISCCP) – google for website – it is broken down into ocean basins, land vs ocean, and different landmasses, but it takes them a while to update.
I’ve done an analysis for patterns – summarised in my book ‘Chill: a reassessment of global warming theory’ and with more detailed graphs in supplementary material on my website: http://www.ethos-uk.com – but I did not have the resources for a proper statistical analysis. You can see a pattern in some data that relates to the solar max and minimum over the 11 year cycle – but the patterns are disrupted by El Nino and major volcanic events – and then there is a major ‘shift’ or phase-change around 2001 when a decadal trend (from the beginning of ISCCP data in 1983) of 5% thinning cloud (especially low level) halted with a step up (about 3%) and it has remained at that level, with some percentage shifts of low and high level cloud contributions.
These cloud patterns can explain THE WHOLE of the ‘global warming’ signal in terms of the 1980-2000 temperature changes – in that Short Wave not Long Wave radiation is driving the warming – and it is stored in the ocean surface waters then transferred landward by cyclonic weather systems. Likewise the percentage shift in 2001 can explain the recent cooling – but with a time-lag due to the heat stored in the northern Pacific and Atlantic gyres (very little extra heat was stored in the southern oceans). The Pacific shifted into a cool-phase late in 2006 (the PDO) when the heat store was exhausted. That heat had been transferred to Alaska and the Arctic basin by currents and cloud. Now it is gone, Alaska is cold again. The same will happen to the North Atlantic – which showed signs of a phase-shift over the last two years.
My sense is that Svensmark’s effect operates but it is not dominant – the main pattern is set by ocean oscillations.
And Jim: I agree with TonyB and others – the contrails can have only localised effects. It is now known, for example, that the ‘global dimming’ that was thought due to anthropogenic sulphur emissions reflecting sunlight, was a natural phenomenon related to natural aerosols and ocean cycles – which shifted in 1979 – again mainly in the Pacific – the man-made pollution was too localised to significantly affect global temperatures (70% of the planet surface is ocean).
You are missing the point some of you and one very particular outburst which is not acceptable whether you tell it like it is or not.
Lief said :
The point of interest is that over the year of the minimum, the levels of the red and the blue are very much the same, even though the following cycles [19 and 24] look to be very different, so the minimum level of F10.7 is not a good predictor of the next cycle.
READ it very carefully, please
Thanks all for the ideas and links about contrails. It sounds as if they have some positive feedback characteristics, but maybe by only a small amount overall.
Jim
vukcevic (08:54:00) :
‘Wriggle matching is not science’ I was told on numerous occasions!
And told here and now one more time. The wiggle matching in my case is immaterial to the point, namely that the ‘bottoms’ are very similar. Slide the two graphs a bit so that the 27-day peaks don’t line up and the conclusion that the two bottom are similar is not changed. The wiggle matching was to illustrate another point, namely that there is 27-day recurrence in both graphs, so that if one set of peaks line up many other [but not all] will do too with absolutely no significance beyond that. E.g. one should not construe the match to mean that a peak in 2008 is in any way related to [or caused by] a peak in 1954.
SteveSadlov (08:49:54) :
The blue curve appears to have a higher SNR versus the red one.
Every wiggle in both curves is ‘signal’. The noise is of the order of the thickness of the lines. What you mean is that the variance of the red curve is higher than that of the blue curve. This follows from cycle 18 being more active than cycle 23. The plot was designed to show that the average level during this minimum is not significantly different from the average level during the 1954 minimum.
Kath (08:55:55) :
The 1954 to cycle 24 overlay is a bit too arbitrary for my liking. I think it would be better to see a two cycle (23-24) F10.7 plot then compare it to another, similar, cycle.
there isn’t any. Data only started in 1947. The point was only to show that the level in 1954 is not too different from what we see now and that since cycle 19 was very high and cycle 24 doesn’t look too hot, the minimum level of F10.7 is evidently not a good predictor of the next cycle.
Gary Pearse (09:05:44) :
you stating that it had already begun and that rising “activity” of a non-sunspot variety was already heralding the new cycle. Could it be that this illustration is a forecast that you can disown – “after all, I did say that 10.7 was not a predictor.”
It is plain that F10.7 is rising and that cycle 24 has begun. That is not what my graph was about. The point was that since the level of F10.7 at minimum in 1954 was not much different from 2008, that the level is not a good predictor. That the new cycle is here is not a prediction but just a fact.
and looking at his graph, I’m not sure of your humility. Actually, vukcevic’s equation certainly looks good so far, as good as anything else put forward on the subject.
I’m not humble at all [au contraire], just trying to be scientifically correct. What Vuk omits is that his equation ‘predicts’ that in 1965 the polar fields would have been even bigger than anything measured since, and all the [indirect] data we have suggests otherwise.
Nasif Nahle (09:22:35) :
We could expect the enhancement of the solar power in the next months and increasing of the fluctuations of the surface temperatures with it.
I’ll agree with the first half, but remark that the increase will likely be a lot smaller than it was in 1956. I’ll say that there is no good evidence that supports the second half.
Hank (09:27:17) :
Has anyone wondered about why it is that solar cycles vary in length? And whether it’s a portent of what will happen in succeeding cycles?
Many have wondered a lot about that. The current ideas go something like this: Solar activity is created by dynamo amplification of flux left over from the previous cycle(s). The dynamo works by circulating plasma around in inside the Sun. The speed of the circulation is inversely related to how much amplification you get [the longer it takes, the more time for amplification], but the magnetic field itself works back on the circulation [stronger field tending to brake the flow], so you have a very complicated non-linear feedback situation. A somewhat technical [but readable] review can be found here: http://arxiv.org/PS_cache/arxiv/pdf/0906/0906.4748v1.pdf
Statistically, looking at past cycles, large cycles tend to [but not always] be short and small cycles long, so one might guess [‘predict’] that the coming few cycles will be longer than average.
Leif
Did the atmospheric atomic bomb testing affect the measurement of the 10.7 solar radio flux?
I agree that the F10.7 isn’t telling us a whole lot here, because it can’t tell us what it is going to do next.
The parts that match up between 1954 and 2008 belie the means by which both got there.
They arrived differently.
Try the active regions of the Sun for a much better comparison, and one which will tell you if the current status is unusual or not. That record goes back to the late 1870’s.
edcon (10:20:36) :
Did the atmospheric atomic bomb testing affect the measurement of the 10.7 solar radio flux?
No
rbateman (10:24:23) :
Try the active regions of the Sun for a much better comparison, and one which will tell you if the current status is unusual or not. That record goes back to the late 1870’s.
The current minimum is very much like 1901-1902, with the cycle just before [#13] very much like cycle 24, and the coming cycle [#24] predicted to be much like cycle 14. We shall see. One thing that was unusual about #14 was the very large swings with a period of about a year: http://www.solen.info/solar/cycl14.html
It is not known if SC24 will show similar swings. It will be interesting to watch the reactions when we get the first large upswing [people shouting: see, a large cycle!] and the first large dip [people shouting: see, I told you we are in a Grand Minimum]. This can go back and fourth some ~five times, if SC14 is any guide 🙂
I’m not sure why people are talking about “wiggle matching”. The only thing Leif discredited as having predictive power is the absolute level of the F10.7 cm. This is, effectively, the two plots with all high-frequency wiggle removed.
If I understand him correctly, he is simply saying that the minimum F10.7cm value now matches that of 1954 and that 1954 had a large cycle succeeding this. In other words, pull the lowest point (or points for those of you who like smoothing) from each plot and compare them. Nothing more.
I’m happy with Leif’s main point which is that the minimum level of the 10.7 flux is not an indicator of anything and the point is well made by his chart.
As far as I can see Leif was not intending to say anything about the possible effect of a weak cycle as against a strong cycle or the length of a cycle or the length of successive cycles so criticism based on that aspect is misguided.
I see Peter Taylor’s comments as especially pertinent for those who are inclined to accept a solar influence but I would say that ocean SST changes drive cloudiness changes with the Svensmark idea being either a small influence or a mirage.
The solar variations require multiple cycles to show an effect such as the slow progression from Roman Warm Period to Dark Ages to Mediaeval Warm Period to Little Ice Age to the recent Grand Maximum.
Within those long slow solar cycles over centuries there are much greater oceanic cycles which can offset or supplement the solar variations weakly or strongly at different times.
Two key parameters need further research to supplement the background solar trend :
i) The net warming or cooling effect of ALL the ocean cycles combined at any given time which dictates the flow of stored solar energy from ocean to air.
ii) The net latitudinal position of ALL the air circulation systems combined at any given time which dictates the rate of energy flow from air to space.
Combine those parameters with variations in solar input and all observed global changes in temperature trend and all observed changes in regional climate or weather can be explained without reference to changes in GHGs.
GHGs follow the system. They cannot lead it otherwise the natural swings in global humidity would have prevented the development of oceans of water in the first place.
Dennis Sharp (08:03:11) :
What are you people talking about, Leif has explained many times that the sun only has the effect of a light bulb on earth temperatures. Earth doesn’t get hotter or colder because the sun is active or inactive. The variation of TSI proves it, so forget your intuition. It is getting cooler because of the negative phase of PDO and possibly AMO, and the only thing that drives the oceans is the steadiness of the sun. Just because a million earths could fit inside the sun doesn’t mean it has any significant affect on us here. We are just spectators for a world far, far away. We can predict what we know for sure. Just ask David Hathaway and team at NASA.
The Earth is not an isolated system, either a thermos…