Guest post by Alec Rawls
Study of the sun-climate link was energized in 1991 by Friis-Christensen and Lassen, who showed a strong correlation between solar-cycle length and global temperature:
This evidence that much of 20th century warming might be explained by solar activity was a thorn in the side of the newly powerful CO2 alarmists, who blamed recent warming on human burning of fossil fuels. That may be why Lassen and Thejll were quick to offer an update as soon as the 1997-98 El Nino made it look as if temperatures were suddenly skyrocketing:
The rapid temperature rise recently seems to call for a quantitative revisit of the solar activity-air temperature association …
We conclude that since around 1990 the type of Solar forcing that is described by the solar cycle length model no longer dominates the long-term variation of the Northern hemisphere land air temperature.
In other words, there was now too much warming to account for by solar cycle length, so some other factor, such as CO2, had to be driving the most recent warming. Of course everyone knew that the 1998 warming had actually been caused by ocean oscillations. Even lay people knew it. (El Nino storm tracks were all the news for six months here in California.)
When Lassen was writing his update in mid ’99, temperatures had already dropped back to 1990 levels. His 8 year update was outdated before it was published. 12 years later the 2010 El Nino year shows the same average temperature as the ’98 El Nino year, and if post-El Nino temperatures continue to fall off the way they did in 99, we’ll be back to 1990 temperatures by mid-2011. Isn’t it about time Friis-Cristensen, Lassen and Thejll issued another update? Do they still think there has been too much recent warming to be accounted for by solar activity?
The most important update may be the discovery that, where Lassen and his colleagues found a correlation between the length of a solar-cycle and temperatures over that cycle, others have been finding a much stronger correlation to temperatures over the next cycle (reported at WUWT this summer by David Archibald).
This further correlation has the advantage of allowing us make projections. As Archibald deciphers Solheim’s Norwegian:
since the period length of previous cycle (no 23) is at least 3 years longer than for cycle no 22, the temperature is expected to decrease by 0.6 – 1.8 degrees over the following 10-12 years.
Check out this alarming graphic from Stephen Strum of Frontier Weather Inc:
The snowed in Danes might like to see these projections, before they bet the rest of their climate eggs on a dangerous war against CO2.
From sins of omission to sins of commission
In 2007, solar scientist Mike Lockwood told the press about some findings he and Claus Frohlich had just published:
In 1985, the Sun did a U-turn in every respect. It no longer went in the right direction to contribute to global warming. We think it’s almost completely conclusive proof that the Sun does not account for the recent increases in global warming.
Actually, solar cycle 22, which began in 1986, was one of the most intense on record (part of the 20th century “grand maximum” that was the most active sun of the last 11 thousand years), and by almost every measure it was more intense than solar cycle 21. It had about the same sunspot numbers as cycle 21 (Hathaway 2006):
Cycle 22 ran more solar flux than cycle 21 (via Nir Shaviv):
Cycle 22 was shorter than cycle 21 (from Joseph D’Aleo):
Perhaps most important is solar activity as measured (inversely) by the cosmic ray flux (which many think is mechanism by which solar activity drives climate). Here cycle 22 is THE most intense in the 60 year record, stronger even than cycle 19, the sunspot number king. From the Astronomical Society of Australia:
Some “U-turn in every respect.”
If Lockwood and Frohlich simply wanted to argue that the peak of the modern maximum of solar activity was between solar cycles 21 and 22 it would be unobjectionable. What difference does it make exactly when the peak was reached? But this is exactly where their real misdirection comes in. They claim that the peak of solar activity marks the point where any solar-climate effect should move from a warming to a cooling direction. Here is the abstract from their 2007 Royal Society article:
Abstract There is considerable evidence for solar influence on the Earth’s pre-industrial climate and the Sun may well have been a factor in post-industrial climate change in the first half of the last century. Here we show that over the past 20 years, all the trends in the Sun that could have had an influence on the Earth’s climate have been in the opposite direction to that required to explain the observed rise in global mean temperatures.
In order to assert the need for some other explanation for recent warming (CO2), they are claiming that near peak levels of solar activity cannot have a warming effect once they are past the peak of the trend—that it is not the level of solar activity that causes warming or cooling, but the change in the level—which is absurd.
Ken Gregory has the most precise answer to this foolishness. His “climate smoothing” graphic shows how the temperature of a heat sink actually responds to a fall-off in forcing:
“Note that the temperature continues to rise for several years after the Sun’s forcing starts to decrease.”
Gregory’s numbers here are arbitrary. It could be many years before a fall off in forcing causes temperatures to start rising. In the case of solar cycle 22—where if solar forcing was actually past its peak, it had only fallen off a tiny bit—the only way temperature would not keep rising over the whole solar cycle is if global temperature had already equilibrated to peak solar forcing, which Lockwood and Frohlich make no argument for.
The obvious interpretation of the data is that we never did reach equilibrium temperatures, allowing grand maximum levels of solar activity to continue to warm the planet until the sun suddenly went quiet. Now there’s an update for Lockwood and Frohlich. How about telling the public when solar activity really did do “U” (October 2005).
Usoskin, Benestad, and a host of other solar scientists also mistakenly assume that temperature is driven by trend instead of level
Maybe it is because so much of the evidence for a sun-climate link comes from correlation studies, which look for contemporaneous changes in solar activity and temperature. Surely the scientists who are doing these studies all understand that there is no possible mechanism by which the rate of change in solar activity can itself drive temperature. If temperature changes when solar activity changes, it is because the new LEVEL of solar activity has a warming or cooling effect.
Still, a remarkable number of these scientists say things like this (from Usoskin et al. 2005):
The long term trends in solar data and in northern hemisphere temperatures have a correlation coefficient of about 0.7 — .8 at a 94% — 98% confidence level. …
… Note that the most recent warming, since around 1975, has not been considered in the above correlations. During these last 30 years the total solar irradiance, solar UV irradiance and cosmic ray flux has not shown any significant secular trend, so that at least this most warming episode must have another source.
Set aside the other problems with Usoskin’s study. (The temperature record he compared his solar data to is Michael Mann’s “hockey stick.”) How can he claim overwhelming evidence for a sun-climate link, while simultaneously insisting that steady peak levels of solar activity can’t create warming? If steady peak levels coincide with warming, it supposedly means the sun-climate link is now broken, so warming must be due to some other cause, like CO2.
It is hard to believe that scientists could make such a basic mistake, and Usoskin et al. certainly have powerful incentive to play dumb: to pretend that their correlation studies are finding physical mechanisms by which it is changes in the level of solar activity, rather than the levels themselves, that drive temperature. Just elide this important little nuance and presto, modern warming gets misattributed to CO2, allowing these researchers to stay on the good side of the CO2 alarmists who control their funding. Still, the old adage is often right: never attribute to bad motives what can just as well be explained by simple error.
And of course there can be both.
RealClimate exchange on trend vs. level confusion
Finally we arrive at the beginning, for me anyway. I first came across trend-level confusion 5 years ago at RealClimate. Rasmus Benestad was claiming that, because post 1960’s levels of Galactic Cosmic Radiation have not been trending downwards, GCR cannot be the cause of post-60’s warming.
But solar activity has been well above historical norms since the 40’s. It doesn’t matter what the trend is. The solar-wind is up. According to the GCR-cloud theory, that blows away the GCR, which blows away the clouds, creating warming. The solar wind doesn’t have to KEEP going up. It is the LEVEL that matters, not the trend. Holy cow. Benestad was looking at the wrong derivative (one instead of zero).
A few months later I took an opportunity to state my rebuttal as politely as possible, which elicited a response from Gavin Schmidt. Here is our 2005 exchange:
Me: Nice post, but the conclusion: “… solar activity has not increased since the 1950s and is therefore unlikely to be able to explain the recent warming,” would seem to be a non-sequitur.
What matters is not the trend in solar activity but the level. It does not have to KEEP going up to be a possible cause of warming. It just has to be high, and it has been since the forties.
Presumably you are looking at the modest drop in temperature in the fifties and sixties as inconsistent with a simple solar warming explanation, but it doesn’t have to be simple. Earth has heat sinks that could lead to measured effects being delayed, and other forcings may also be involved. The best evidence for causality would seem to be the long term correlations between solar activity and temperature change. Despite the differences between the different proxies for solar activity, isn’t the overall picture one of long term correlation to temperature?
[Response: You are correct in that you would expect a lag, however, the response to an increase to a steady level of forcing is a lagged increase in temperature and then a asymptotic relaxation to the eventual equilibrium. This is not what is seen. In fact, the rate of temperature increase is rising, and that is only compatible with a continuing increase in the forcing, i.e. from greenhouse gases. – gavin]
Gavin admits here that it’s the level of solar activity, not the trend in solar activity, that drives temperature. He’s just assuming that grand maximum levels of solar forcing should have bought the planet close to equilibrium temperature before post-80’s warming hit, but that assumption is completely unwarranted. If solar activity is driving climate (the hypothetical that Schmidt is analyzing), we know that it can push temperatures a lot higher than they are today. Surely Gavin knows about the Viking settlement of Greenland.
The rapid warming in the late 90’s could easily have been caused by the monster solar cycle 22 and there is no reason to think that another big cycle wouldn’t have brought more of the same. Two or three more cycle 22s and we might have been hauling out the longships, which would be great. No one has ever suggested that natural warming is anything but benign. Natural cooling bad, natural warming good. But alas, a longer grand maximum was not to be.
Gavin’s admission that it is level not trend that drives temperature change is important because ALL of the alarmist solar scientists are making the trend-level mistake. If they would admit that the correct framework is to look at the level of forcing and the lapse to equilibrium then they would be forced to look at the actual mechanisms of forcing and equilibration, instead of ignoring key forcings on the pretense that steady peak levels of forcing cannot cause warming.
That’s the big update that all of our solar scientists need to make. They need to stop tolerating this crazy charade that allows the CO2 alarmists to ignore the impact of decades of grand maximum solar activity and misattribute the resulting warming to fossil fuel burning. It is a scientific fraud of the most disastrous proportions, giving the eco-lunatics the excuse they need to unplug the modern world.
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oneuniverse says:
January 6, 2011 at 12:34 pm
The Muscheler et al. analysis is seriously flawed and shouldn’t be relied upon – whether the flawed results are consistent with the results in some other papers is surely irrelevant.
I don’t think so. And certainly his coauthors of the 2007 paper don’t either.
Why are you relying upon the Steinhilber reconstruction which you’d earlier rejected as using an invalid calibration (in the earlier referenced Scaffeta thread) ?
My problem with Steinhilber is that his calibration is wrong [he even quotes negative numbers of the magnetic field strength] for a very low modulation parameter. The high values are ok.
I noticed that Cliver has abandoned the 4.6 nT number, and is now arguing for a ~ 2.8 nT floor.
What he points out is that the floor of 4 nT has two components to it. A ‘basement’ if you will of 2.8 and a polar field componet making up the rest.
I assume you’re referring to Bergrenn et al. 2009, “A 600-year annual 10Be record from the NGRIP ice core, Greenland”, which concludes : “We observe that although recent 10Be flux in NGRIP is low, there is no indication of unusually high recent solar activity in relation to other parts of the investigated period.”
I think we should let the authors stand by their statement.
In 2006, Ahmad et al. (“Improved measurement of the Ti44 half-life from a 14-year long study”) calculated the half-life to be 58.9 +/- 0.3 years.
Bonino et al on 2006: http://www.springerlink.com/content/f7mh46q822504630/
measure a half-life of 66.6 years.
Leif:
I don’t think so. And certainly his [Muscheller’s] coauthors of the 2007 paper don’t either.
Solanki et al..’s reply to Muscheler currently stands without further reply in the peer-reviewed literature. Their criticism of Muscheler is reasonable and fairly devastating. Most significantly :
Leif:
My problem with Steinhilber is that his calibration is wrong [he even quotes negative numbers of the magnetic field strength] for a very low modulation parameter. The high values are ok.
You wrote earlier of Steinhilber et al. : In Figure 6 they have a dip ~1890. We and our ‘competitors’ [Lockwood, Rouillard, et al.] agree that there is no such dip. This shows that B is greatly underestimated for low values of phi, which is indeed the reason for the sharp dips below the floor.
From Steinhilber’s Fig. 1, phi is a little over 300 at 1890. While this is outside the range of the observational data (lower bound ~400), the differences between your proposed straight line and Steinhilber’s powerlaw curve fits are small at these values, as can be seen at Fig. 2 (using the better fit of linearly varying Phi with solar wind speed). From Fig. 1, most of 1710 onwards remains above 300 (bar ~30 years, which just dip below), and above 400 (bar ~80 years). Therefore at least the last three centuries (almost) can at be considered under your criticism.
Fig. 1 shows phi rising for the last over the last 300 years (although depressed in the 19thC compared to both 18thC and 20thC). A solitary peak in 1740 is of comparable amplitude to the 20th c. peaks, but the latter span a longer period. This would be evidence in support of the hypothesis that 20c has had higher levels of solar activity than the preceding few centuries.
Leif:
What he [Cliver and Ling] points out is that the floor of 4 nT has two components to it. A ‘basement’ if you will of 2.8 and a polar field componet making up the rest.
Not quite, Cliver and Ling wrote: “These correlations suggest that at 11-year minima, B consists of i) a floor of ~2.8 nT, and ii) a component primarily due to the solar polar fields that varies from ~0 nT to ~3 nT. The solar polar fields provide the “seed” for the subsequent sunspot maximum. ”
The polar fields are hypothesised to vary from ~0 to ~ 3nT, so the floor is the basement value ~2.8 nT.
Leif:
I think we should let the authors [Bergrenn et al. 2009] stand by their statement.
They write that “there is no indication of unusually high recent solar activity in relation to other parts of the investigated period”, but they don’t contest the latter half of the 20C has lower 10Be flux, indicating probable higher solar activity, than the rest of the 600 year record, a fact apparent from a visual inspection of their Fig 1.
Leif:
Bonino et al on 2006: http://www.springerlink.com/content/f7mh46q822504630/
measure a half-life of 66.6 years.
The Bonino study uses Ge spectroscopy to measure gamma activity from meteorites that fell in the last three solar cycles. I can’t actually tell if they derive their 66.6 year value or are just quoting it (I only have access to the abstract). A 44Ti half-life of 66.6 happens to be the result of Alburger and Harbottle 1990, so it may be simply a reference to a previous result. (Table 1 of Hashimoto 2000 lists ten different estimates since 1965.)
The Ahmad et al 2006 study is a superior experiment as it uses Ge spectroscopic measurements of pure source 44Ti and 60C, taken over 14 years in two separate laboratories. Their 2006 result of 58.9 +/- 0.3 yrs is an improved version of their 1999 calculation of 59.0 +/- 0.6 yrs, taking advanatage of their accumulated extra years of measurements.
The result of their careful study (with “special efforts to check for systematic errors”) is corroborated by the laboratory experimenta of Hashimoto et al 2000, which reports 59 +/- 2 years. In earlier studies, Norman et al. 1998 reported 62.0 +/- 2.0 yrs, Gorres et al.1998 reported 60.3 +/- 1.3 yrs, Wietfieldt et al. 60.7 +/- 1.2 yrs.
oneuniverse says:
January 6, 2011 at 5:50 pm
Solanki et al..’s reply to Muscheler currently stands without further reply in the peer-reviewed literature.
Nonsense, Muscheler’s 2007 paper is a reply in effect. There is no furyer reply in Nature, because Nature discourages such back-and-forth.
Direct balloon-borne measurements show that the cosmic-ray intensity before AD 1950 had a strong declining trend.
this is the same assumption that McCracken made when he spliced together the ion-chamber and the neutron monitor data, leading to a spurious jump of the inferred HMF B around 1950. A jump we know didn’t happen, so the criticism can be dismissed.
Therefore at least the last three centuries (almost) can at be considered under your criticism.
which would lead to even higher solar activity in the 18th century.
ii) a component primarily due to the solar polar fields that varies from ~0 nT to ~3 nT. The solar polar fields provide the “seed” for the subsequent sunspot maximum. ”
This is under the assumption that there were no polar fields during the Maunder minimum, and I think that assumption is quite wrong as we know that the cosmic ray modulation continued and that the dynamo was still working which it would not do at a polar field of 0 nT.
they don’t contest the latter half of the 20C has lower 10Be flux, indicating probable higher solar activity, than the rest of the 600 year record, a fact apparent from a visual inspection of their Fig 1.
There is good evidence that the climate has a significant influence [perhaps 50%] on the deposition of 10Be, so we cannot be sure that the 20th century climate is not at work here. See http://www.leif.org/EOS/2009JA014532.pdf
As I said the half-life is uncertain.
There are simpler ways of assessing solar activity than cosmic ray radionuclides [which are controlled by poorly understood processes, especially the deposition]. I have collected a few graphs to show this: http://www.leif.org/research/Decades%20with%20Equal%20Activity.pdf
Frank Lansner says:
January 6, 2011 at 8:46 am
Leif and others: We DO agree that the solar activity has been larger in the period 1940-2000 than in the last several hundreds years, right? So never mind what we have a Solar activity level high compared to the last many hundred years and thus we shold not at all be surpriced that more decades with a steady high Solar input is accompanied by a temperature increase 1940-2000. So this particular argument against Solar theory appears weak indeed.
The level of the suns effect is depenant on ground temperatures which are totally flawed.
What I find hard to accept is that the majority of the temperature increase is Urban Tmin, there is little or no increase in trend of urban Tmax, there appears to be little rise in trend in rural Tmin or rural Tmax, that is why there is only a small temperature increase or none shown at rural sites.
The UHI number is obviously the difference in trend between the Urban Tmin compared with Urban Tmax and it`s all linked to population growth.
When you take out the difference between rural and urban Tmin the actual 20th century warming is quite small and easily links directly to the suns influence on climate.
http://i446.photobucket.com/albums/qq187/bobclive/Tmin3.png
http://scialert.net/fulltext/?doi=rjes.2011.1.21&org=10
Leif: Nonsense, Muscheler’s 2007 paper is a reply in effect. There is no furyer reply in Nature, because Nature discourages such back-and-forth.
According to Solanki ea 2005, Muscheler ea 2005 inappropriately used a normalised, detrended dataset (I can’t check this since the reference is in an off-line book ). Solanki et al. note that once appropriate data is used, the Muscheler results become largely consistent with their own. Muscheler ea 2007, a separate analysis for the last 1000 years, doesn’t “fix” the specific problems with Muscheler ea 2005 – the latter remains flawed, so I would suggest not relying on its results.
The presented graphs in Muscheler ea 2007 also suggests increasing solar activity (decreasing GCR flux) since the LIA (say from 1700). The peak in 1790 was followed by the trough of the Dalton minimum, and then further increases.
Solanki ea 2005: Direct balloon-borne measurements show that the cosmic-ray intensity before AD 1950 had a strong declining trend.
Leif: this is the same assumption that McCracken made when he spliced together the ion-chamber and the neutron monitor data, leading to a spurious jump of the inferred HMF B around 1950. A jump we know didn’t happen, so the criticism can be dismissed.
Would you mind being more specific – what assumption? The balloon data of cosmic ray intensity does have a declining trend, but unfortunately it doesn’t significantly overlap with the the Climax data.
Leif: There is good evidence that the climate has a significant influence [perhaps 50%] on the deposition of 10Be, so we cannot be sure that the 20th century climate is not at work here. See http://www.leif.org/EOS/2009JA014532.pdf
We discussed Webber and Higbie 2010 – they assumed a constant GCR LIS. Their conclusions with respect to terrestrial 10Be levels are merely speculative.
Leif: As I said the half-life is uncertain.
Estimates of the 44Ti half-life have steadily improved.
You cited a single meteorite study, mentioning in the abstract a 66.6 yr half-life. The study appears to be citing the 1990 paper mentioned above – it seems unlikely that they achieved a good measure half-life by an analysis of a small set of meteorites (if at all – I suspect they just used the cited figur
I cited Ahmad et al 2006 (amongst others), which tackles the difficult problem of measuring half-lives of 10-100 years (the range falls between the good working ranges of the two main techniques of half-life measurement). They achieve progress on the problem partly by doing a long study, 14 years of measurements in two separate labs from pure 44Ti and 60C sources. Their work seems to be a significant achievement, and the result of 58.9 +/- 0.3 years as the half-life of 44Ti is in good agreement with other studies from 1999 onwards..
If you are aware of a better study than this, please bring it forward.
Just for interest, WolframAlpha gives a half-life of 59.9 yrs for 44Ti, but doesn’t cite a source. Wikipedia gives 60.0 yrs, based it seems on studies mostly from the 90’s.
Leif: There are simpler ways of assessing solar activity than cosmic ray radionuclides [which are controlled by poorly understood processes, especially the deposition]. I have collected a few graphs to show this: http://www.leif.org/research/Decades%20with%20Equal%20Activity.pdf
These are restricted to the instrumental period of the last couple of centuries, though.
oneuniverse says:
January 7, 2011 at 3:28 pm
These are restricted to the instrumental period of the last couple of centuries, though.
They show that the ion chamber/neutron monitor jump which Solanki/McCracken rely on did not happen. All the rest then just becomes straw men. The original issue was whether the recent activity is the highest in 10,000 years. Steinhilber’s record is pretty good most of the time [except for those deep dips which are due to incorrect calibration for small modulation parameters. Here is the Steinhilber record [expressed in equivalent HMF field strength: http://www.leif.org/research/Steinhilber-HMF-B.png see for yourself. If you have any beef with Steinhilber, take it up with him.
Leif: They show that the ion chamber/neutron monitor jump which Solanki/McCracken rely on did not happen.
While the Neher ionisation data doesn’t overlap with the Climax data, it does overlap and agree with the Forbush data, which also overlaps and agrees with the Climax data. (See Fig. 2, left panel, of Mewaldt ea 2005). 10Be and 14C records also show decreasing concentration in the first half of 20thC. What is the inconsistency?
oneuniverse says:
January 8, 2011 at 2:23 pm
What is the inconsistency?
The inconsistency is most clearly seen here: http://www.leif.org/EOS/2006JA012117.pdf Figure 7. The big jump ~1950 would result is a 1.7 nT jump in HMF B http://www.leif.org/EOS/2006JA012119.pdf which is not observed. Steinhilber et al and Svalgaard & Cliver and Lockood et al all agree on that, see http://www.leif.org/research/2009JA015069.pdf Figures 11, 13, and 14. So the slicing together of the ion-chamber and neutron monitor data is not correct.
re: Fig. 7 (McCracken & Beer)
It’s a comparison between the sunspot record and neutron monitor counts (as proxies for GCRs). GCRs can vary for reasons other than changes in the HMF, for which sunspots are a limited proxy. The decline before 1950 is not a reason to throw out the data. Remember, in 2009, GCRs broke the space age record (by 19%) since the 50’s. So there’s no reason to rule out that they weren’t also higher before the ’50s.
re: Fig 11,13 & 14 (Svalgaard & Cliver)
Figs. 11-14 (with the exception of one of the 5 recons. in Fig. 14) show increasing HMF B during 1900-1950 , consistent with the ionisation chamber data.
Dr. Svalgaard, I enjoyed reading the discoveries in “Long-term geomagnetic indices and their use in inferring solar wind parameters in the past” (Svalgaard & Cliver 2006).
You refer to an apparent discontinuity in the aa-index around 1957. You note that the discontinuity is not present in the ap-index. Now 1957 happens to be date that the ‘northern’ observatory (of the two observatories used to calculate the aa-index) was relocated to Hartland, so there could be an introduced discontinuity there. I apologise if you’re already aware of this, but I saw no mention of it in the paper.
oneuniverse says:
January 8, 2011 at 5:24 pm
Remember, in 2009, GCRs broke the space age record (by 19%) since the 50′s. So there’s no reason to rule out that they weren’t also higher before the ’50s.
No, they did not. The comparison is flawed as the comparison [for very low energy GCRs] was with the previous minimum, and every other minimum is lower. We know why [has to do with different drift depending on the polarity of the solar polar fields]. An honest comparison would cover the actual data from several stations back to 1952, as in http://www.leif.org/research/Cosmic%20Ray%20Count%20for%20Different%20Stations.png
At this point people trot out Oulu as proof of a change, but that is spurious as Oulu does not maintain a constant calibration over time [that is hard to do], as you can see here: http://www.leif.org/research/Cosmic%20Ray%20Count%20for%20Different%20Stations-Oulu.png
Figs. 11-14 (with the exception of one of the 5 recons. in Fig. 14) show increasing HMF B during 1900-1950 , consistent with the ionisation chamber data.
No, because the ion chamber data predicts a much large increase, which is not observed.
oneuniverse says:
January 8, 2011 at 5:50 pm
Dr. Svalgaard, I enjoyed reading the discoveries in “Long-term geomagnetic indices and their use in inferring solar wind parameters in the past” (Svalgaard & Cliver 2006).
You refer to an apparent discontinuity in the aa-index around 1957. You note that the discontinuity is not present in the ap-index. Now 1957 happens to be date that the ‘northern’ observatory (of the two observatories used to calculate the aa-index) was relocated to Hartland, so there could be an introduced discontinuity there. I apologise if you’re already aware of this, but I saw no mention of it in the paper.
This is a key point as is part of the reason for the discontinuity as we discovered here:
http://www.leif.org/research/IHV%20-%20a%20new%20long-term%20geomagnetic%20index.pdf
There is a bigger problem with the aa-index, namely that it is also too low before 1938:
http://www.leif.org/research/Analysis%20of%20K=0%20and%201%20for%20aa%20and%20NGK.pdf
The only reliable index is our own IHV [and IDV] described here:
http://www.leif.org/research/2007JA012437.pdf and
http://www.leif.org/research/2009JA015069.pdf
http://www.leif.org/research/The%20IDV%20index%20-%20its%20derivation%20and%20use.pdf
oneuniverse: So there’s no reason to rule out that they weren’t also higher before the ’50s.
Leif: No, they did not. The comparison is flawed as the comparison [for very low energy GCRs] was with the previous minimum, and every other minimum is lower. We know why [has to do with different drift depending on the polarity of the solar polar fields].
I noticed that there was a comparison with solar wind pressure from the last minimum in one of NASA’s related press releases, but I didn’t see it for the CRs. According to Dr. Mewaldt : “In 2009, cosmic ray intensities have increased 19% beyond anything we’ve seen in the past 50 years.”.
Note that HMF B and solar wind pressure also broke records in 2008-2009:
“In both 2008 and 2009, the notion of such a [~ 4.6 nT] floor was undercut by annual B averages of ~ 4 nT. ” , Cliver & Ling
“Measurements by the Ulysses spacecraft show that solar wind pressure is at a 50-year low,” according to Dr. Mewaldt, speaking in 2009.
“This is the weakest it’s been since we began monitoring solar wind almost 50 years ago.”, according to Dave McComas of the Southwest Research Institute, reported in Sep. 2008
“What we’re seeing is a long term trend, a steady decrease in pressure that began sometime in the mid-1990s. [..] We’ve only been monitoring solar wind since the early years of the Space Age—from the early 60s to the present,” says Posner. “Over that period of time, it’s unique. How the event stands out over centuries or millennia, however, is anybody’s guess. We don’t have data going back that far.”, according to Arik Posner, NASA’s Ulysses Program Scientist, reported in Sep. 2008.
oneuniverse: Figs. 11-14 (with the exception of one of the 5 recons. in Fig. 14) show increasing HMF B during 1900-1950 , consistent with the ionisation chamber data.
Leif: No, because the ion chamber data predicts a much large increase, which is not observed
The ion chamber data itself has a declining trend before the 50’s.
What prediction are you referring to? A prediction of HMF or GCR flux? Either way, you need to have great confidence in a model before you use a disagreement with the model’s predictions to throw out observational data. What specific prediction an d model are you referring to? (Otherwise it’s mostly handwaving..)
Leif: Steinhilber’s record is pretty good most of the time [except for those deep dips which are due to incorrect calibration for small modulation parameters.
Earlier you wrote : “In Figure 6 they have a dip ~1890. We and our ‘competitors’ [Lockwood, Rouillard, et al.] agree that there is no such dip. This shows that B is greatly underestimated for low values of phi, which is indeed the reason for the sharp dips below the floor. ”
The dip in 1890 isn’t neccesarily deep compared to the deep dips.
I wrote earlier: “From Steinhilber’s Fig. 1, phi is a little over 300 at 1890. While this is outside the range of the observational data (lower bound ~400), the differences between your proposed straight line and Steinhilber’s powerlaw curve fits are small at these values, as can be seen at Fig. 2 (using the better fit of linearly varying Phi with solar wind speed).”
Would you mind quantifying what you mean by a) a deep dip , and b) a (too-)low modulation parameter ?
oneuniverse says:
January 9, 2011 at 10:01 am
According to Dr. Mewaldt : “In 2009, cosmic ray intensities have increased 19% beyond anything we’ve seen in the past 50 years.”
I just showed you the cosmic ray intensity the past 60 years http://www.leif.org/research/Cosmic%20Ray%20Count%20for%20Different%20Stations.png
Mewaldt refers to low-energy cosmic rays which show a much larger modulation. We are probably now where we were 100 years ago.
Note that HMF B and solar wind pressure also broke records in 2008-2009
And again were are for those where we were 100 years ago, so the cosmic rays back then should be as they are now.
What prediction are you referring to? A prediction of HMF or GCR flux? Either way, you need to have great confidence in a model before you use a disagreement with the model’s predictions to throw out observational data. What specific prediction an d model are you referring to? (Otherwise it’s mostly handwaving..)
http://www.leif.org/EOS/2006JA012119.pdf
The observational data has poor absolute calibration.
By now, I have forgotten what it is you are arguing. Remind me. My point is that activity now is what it was a century ago [108 yrs], so with the current understanding of cosmic ray modulation the GCRs should also be.
oneuniverse says:
January 9, 2011 at 10:48 am
Would you mind quantifying what you mean by a) a deep dip , and b) a (too-)low modulation parameter ?
A deep dip is certainly one that shows negative HMF Bs. The problem starts with Figure 2 of Steinhilber’s http://www.leif.org/EOS/2009JA014193.pdf paper, that shows that the modulation parameter goes to zero for B going to zero assuming that all modulation is due to the magnitude of B. The red dots also may suggest a linear relationship that would give B = 4 nT for phi = zero. Too low modulation parameter refer to outside of the domain for which we have data. [red dots in Figure 2].
Dave Springer: I don’t believe your January 6, 2011 at 7:47 am reply answers the question of “How would the pulse remain intact after 1600 years?” either.
By now, I have forgotten what it is you are arguing. Remind me.
Well, I started by pointing out that Muscheler ea 2005 you’d directed warren to was a flawed analysis, which you fought for a while. You raised a few concerns eg about the half-life 44Ti, concerns which I showed to be incorrect.
I think at the moment we’re arguing about whether it’s appropriate to reject the pre-‘space age’ ionisation chamber data (as it stands) because a prediction from a some model, using said data, doesn’t match some other observations.
You hadn’t specified which model, which prediction & which contradicting observations, so I asked “What specific prediction and model are you referring to?”. Your reply was
http://www.leif.org/EOS/2006JA012119.pdf
In that paper, it’s your reconstruction (S&C) that disagrees with the other three (Solanki ea, Lockwood ea, McCracken), so at first glance, one would be tempted to place more confidence in the others. Maybe you’re right and the other three are wrong, but where is the technical argument ? At the moment, you’re just pointing out that they disagree with your reconstruction, something they note themselves. And what is the further argument saying that it’s not their model (or your model) that’s wrong, but the data?
The ionisation chamber data agrees with the cosmogenic proxies, (declining in the first half of the 20th C), which is something that one would predict if one considered both to be measuring CR activity, so that’s a point against your argument (which is still rather vague). On the whole, IMO you’re rather isolated in your position on this matter, and have as yet to provide the necessary argument to support it.
Post above, sorry, that shold have been “kramer”. not “warren”.
Leif: Too low modulation parameter refer to outside of the domain for which we have data. [red dots in Figure 2].
Thank you, ok.
Apologies for the proof-reading mistakes in last two posts (“shold”, “a some model”, “concerns..concerns”).
[Nah – Just consider it proof that you wrote it, and then read it, “write” the first time. 8<) Robt]
oneuniverse: where is the technical argument ?
Found it, I think.
Robt , cheers 😛
Leif, in “Comment on ‘The heliomagnetic field near Earth, 1428-2005’ by K. G. McCracken”, by Svalgaard and Cliver, you wrote:
The 10Be and 14C records are produced by the action of cosmic ray particles, and have a declining trend like the 1933-1951 ionisation data.
eg. see the solar modulation potential inferred from multiple 10Be and 14C records (Fig. 9 & 10) in Muscheler et al. 2007 . They show decreasing trends (and the Wolf and group sunspot numbers – Fig. 11, panel a – are increasing) for the period 1900-1950, and I think 1930-1950, although the graphs are a little cramped horizontally to make it easy. Looking for a higher resolution graph, I found this already open in my browser – Beer et al. 1994, Fig. 5, 14C measured (from Stuiver and Braziunas 1993), which shows 1930-1951 having a declining concentration. It’s a little late here though – I’ll have a look tomorrow.
I’ll have a look tomorrow
Along with Beer 1994 and Muscheler ea. 2007, I found Usoskin ea 2002 , Fig. 4 (10Be) and Usoskin ea 2005, Fig. 2 (SN derived from 10Be & 14C).
In disagreement, I found Berggren 2009, NGRIP & Dye 3, Fig. 3 (10Be), which shows a flat trend for 1930-1950. However, Muscheler ea 2007, Fig. 8 brings together the Dye 3, Dome C and Southpole cores (10Be deposition has regional variations, so benefits from an analysis using multiple cores) and shows the declining trend.
Leif, in your reply to McCracken, as part of your reasoning for why the 1933-1951 ionisation chamber data needs to be questioned, you wrote : “For each of these series, the HMF at the 1944 and 1954 minima is essentially constant at ~5 nT (Figure 2).”
Yes, but the maxima are increasing, in the fig. 2 reconstructions.
The sunspot numbers from SIDC also have increasing maxima . Picking years with lowest & highest SSN :
1937.5 — 114.4
1944.5 — 9.6
1947.5 — 151.6
1954.5 — 4.4 ,
1957.5 — 190.2
Picking years either side of the maximum counts also gives a rising maximum.
Leif: The [ionisation chamber] observational data has poor absolute calibration.
As well as agreement with the neutron monitor data and the cosmogenic proxies, the Neher i.chamber data overlaps 1957–1969 with the LPI group’s radiosonde ionisation measurements (longest-running measurements available). Please refer to fig. 4 of “Cosmic Ray Induced Ion Production in the Atmosphere” (Bazilevskaya ea 2007).
Please see fig. 4, where excellent agreement is shown for three different altitudes.
The erronous drift should be visible in the comparison (unless both group’s instruments drifted identically – unlikely as the LPI group use different apparatus and design), but it isn’t. So if, as you assert, there was a calibration problem, it had been solved by 1957. Is there some some flaw in their methods or instruments pre-1957 that you’re aware of?
Sorry, “groups'” , not “group’s” .. it’s late again, so bidding a good night.
[ Are you sure? 8<) Thank you for contributing. Robt]