Readers may find the title familiar, that’s because Basil Copeland and I also did a paper looking at solar signatures in climatic data, which has received a lot of criticism because we made an analytical error in our attempt. But errors are useful, teachable moments, even if they are embarrassing, and our second attempt though, titled,
hasn’t been significantly challenged yet that I am aware of. Basil and I welcome any comments or suggestions on that work.
In our work, we used Hodrick-Prescott filtering to extract the solar cycle signal from the HadCRUT temperature dataset. In this paper the data are extracted from the ECA&ECD database (available via http://eca.knmi.nl ). According to the paper, they are “using a nonlinear technique of analysis developed for time series whose complexity arises from interactions between different sources over different time scales”. Read more about it in the paper. In both our paper, and in this one, a solar signature is evident in the temperature data. – Anthony
Evidence for a solar signature in 20th-century temperature
By Jean-Louis Le Mouel, Vincent Courtillot, Elena Blanter, Mikhail Shnirman (PDF available here)
J.-L. Le Mouël et al., Evidence for a solar signature in 20th-century temperature data from the USA and Europe, C. R. Geoscience (2008), doi:10.1016/j.crte.2008.06.001
Abstract
We analyze temperature data from meteorological stations in the USA (six climatic regions, 153 stations), Europe (44 stations, considered as one climatic region) and Australia (preliminary, five stations). We select stations with long, homogeneous series of daily minimum temperatures (covering most of the 20th century, with few or no gaps).We find that station data are well correlated over distances in the order of a thousand kilometres. When an average is calculated for each climatic region, we find well characterized mean curves with strong variability in the 3–15-year period range and a superimposed decadal to centennial (or ‘secular’) trend consisting of a small number of linear segments separated by rather sharp changes in slope.
Our overall curve for the USA rises sharply from 1910 to 1940, then decreases until 1980 and rises sharply again since then. The minima around 1920 and 1980 have similar values, and so do the maxima around 1935 and 2000; the range between minima and maxima is 1.3 °C. The European mean curve is quite different, and can be described as a step-like function with zero slope and a ~1 8°C jump occurring in less than two years around 1987. Also notable is a strong (cold) minimum in 1940. Both the USA and the European mean curves are rather different from the corresponding curves illustrated in the 2007 IPCC report.We then estimate the long-term behaviour of the higher frequencies (disturbances) of the temperature series by calculating the mean-squared interannual variations or the ‘lifetime’ (i.e. the mean duration of temperature disturbances) of the data series.We find that the resulting curves correlate remarkably well at the longer periods, within and between regions. The secular trend of all of these curves is similar (an S-shaped pattern), with a rise from 1900 to 1950, a decrease from 1950 to 1975, and a subsequent (small) increase. This trend is the same as that found for a number of solar indices, such as sunspot number or magnetic field components in any observatory. We conclude that significant solar forcing is present in temperature disturbances in the areas we analyzed and conjecture that this should be a global feature.
…
We find that station data are well correlated over distances in the order of a thousand kilometres. When an average is calculated for each climatic region, we find well characterized mean curves with strong variability in the 3-15-year period range and a superimposed decadal to centennial or ‘secular’ trend consisting of a small number of linear segments separated by rather sharp changes in slope. Our overall curve for the USA rises sharply from 1910 to 1940, then decreases until 1980 and rises sharply again since then. The minima around 1920 and 1980 have similar values, and so do the maxima around 1935 and 2000; the range between minima and maxima is 1.38C. The European mean curve is quite different, and can be described as a step-like function with zero slope and a 1.8C jump occurring in less than two years around 1987. Also notable is a strong (cold) minimum in 1940. Both the USA and the European mean curves are rather different from the corresponding curves illustrated in the 2007 IPCC report.
…
We then estimate the long-term behaviour of the higher frequencies (disturbances) of the temperature series by calculating the mean-squared interannual variations or the ‘lifetime’ (i.e. the mean duration of temperature disturbances) of the data series. We find that the resulting curves correlate remarkably well at the longer periods, within and between regions. The secular trend of all of these curves is similar (an S-shaped pattern), with a rise from 1900 to 1950, a decrease from 1950 to 1975, and a subsequent (small) increase. This trend is the same as that found for a number of solar indices, such as sunspot number or magnetic field components in any observatory.
…
We conclude that significant solar forcing is present in temperature disturbances in the areas we analyzed and conjecture that this should be a global feature.
We have also shown that solar activity, as characterized by the mean-squared daily variation of a geomagnetic component (but equally by sunspot numbers or sunspot surface) modulates major features of climate. And this modulation is strong, much stronger than the one per mil variation in total solar irradiance in the 1- to 11-year range: the interannual variation, which does amount to energy content, varies by a factor of two in Europe, the USA and Australia. This result could well be valid at the full continental scale if not worldwide. We have calculated the evolution of temperature disturbances, using either the mean-squared annual variation or the lifetime. When 22-year averaged variations are compared, the same features emerge, particularly a characteristic centennial trend (an S-shaped curve) consisting of a rise from 1920 to 1950, a decrease from 1950 to 1975 and a rise since. A very similar trend is found for solar indices. Both these longer-term variations, and decadal and sub-decadal, well-correlated features in lifetime result from the persistence of higher frequency phenomena that appear to be influenced by the Sun. The present preliminary study of course needs confirmation by including regions that have not yet been analyzed.
Pamela Gray (18:02:34) :
The argument here is whether or not the Sun changes in additional ways to affect the larger temperature swings we experience over decades or if it is an endogenous phenomenon. There are hypothesized mechanisms available for endogenous drivers that far outweigh in number, strength, and plausibility any hypothesized solar drivers of variability. It remains, at the end of the day, that endogenous drivers rule, so far.
Yes, Pamela, that’s the argument here. Nobody is rejecting the idea on the existence of intrinsic and/or inherent factors which drive the climate of Earth. For example, the ocean acts as a thermoregulator. However, the Sun has been, is and will be always the primary source of energy and every change in the intensity of its radiation has been, is and will be affecting the climate on the Earth. I am talking about global climate.
The carbon dioxide has not thermophysical properties as to cause climate changes; it is not a primary source of energy, so we cannot say it “heats up the Earth”. What heats up the Earth is the Sun and the change of temperature of the Earth is directly proportional to the load of heat incoming from the Sun. If the Sun diminishes its output of energy, the load of energy received by the Earth would be lesser, etc.
Pamela Gray (18:02:34):
Addendum: To say that a solar flare or the absence of solar flares doesn’t affect the load of energy received by the Earth and its climate is non sense.
Nasif Nahle (21:29:05) :
Addendum: To say that a solar flare or the absence of solar flares doesn’t affect the load of energy received by the Earth and its climate is non sense.
This is stated in the usual nonsensical way. Of course, there is an effect. The question is how big the effect is. And it is very, very, very small, so it will have no measurable impact. One of the biggest flares ever gave a 267 parts per million [or 0.3 W/m2] increase in the total energy we got from the Sun at the maximum of the flare. And such superflares are very rare. Overall, the extra energy we get from flares is negligible.
Clarification: The references are for background information. The analyses are mine – and the Chandler wobble reversal in 1931 was a terrestrial event.
Some want to continue believing in Santa Claus.
You can lead horses to water but you can’t make them drink.
It is not sensible to argue with people who have an agenda.
Re: Pamela Gray (18:02:34)
Terrestrial polar motion occurs on Earth.
This solar/geomagnetic stuff is way over my head and seems to be generating more delta-T than delta-Lux…
To return to Paul Vaughan’s point about the meaning of “running mean” – apologies if I’ve used the wrong term here. The “mean” step on WFT does the second of your two, which you called “moving average” – that is it averages N samples *centered at the plotted point* – hence losing N/2 samples at each end, but retaining the phase relationships. Does anyone else think “running mean” is the wrong term for this? If so, I’ll correct the help page which mentions it.
“isolate” simply subtracts the mean (moving average) centered at the sample from the sample itself – it’s a primitive kind of high-pass filter. So for example you could roughly select signals between 5 and 20 years period with:
http://www.woodfortrees.org/plot/hadcrut3vgl/isolate:240/mean:60
Finally, Paul expanded on the original paper’s method for generating the curves:
“They calculated year-over-year differences at daily resolution, squared these differences, and then boxcar-averaged them at 22 year bandwidth. This gives a series of 22-year-summaries of the intensity of year-over-year changes at daily resolution.”
Yes, as through a glass, darkly, I had gathered something like that – but what I don’t get is what it actually means! Are they effectively taking a differential (=>phase shift?), and what’s the significance of the 22 years – could it be acting (as I had guessed visually) as a high-pass filter?
Put another way, are they “cherry-picking” their processing algorithm as well as the data range, to get two curves that happen to trend down at roughly the same time?
Paul Vaughn
I have checked the NOAA data for monthly and hourly CO2 data and it is basically the same plot as for CDIAC monthly and NOAA houly. About a 2 week lag between month and hourly.
I did not follow your suggestion as no time. I have suggested that you show what I am supposed to see. But you come back with more stuff – just no time with a full time job and family to do this stuff. Please show all here what you have discovered!
As to finding a solar influence on temperatures in the noise of the FFTs As I (and Leif) have stated – there is a signal somewhere in the noise – increase solar radiation and you will increase temperature) We are not trying to prove it is there, we KNOW it is. All the filtering, differentiation, signal analysis will eventually pick up the solar signiature this is not in dispute. It is SIMPLY that the signiature is so far in the general noise of temperature fluctuation that it can be ignored.
Nasif Nahle (21:25:36) : What heats up the Earth is the Sun and the change of temperature of the Earth is directly proportional to the load of heat incoming from the Sun
This statement is inaccurate (but approximate)
1. Taking the earth as a black body radiator as the earth heats it will non linearly lose more radiation.
2 As the earth heats More cloud / water vapour less ice etc will cause a non linear effect.
Solar radiation controls temperature but in a nonlinear complex manner.
Leif Svalgaard (21:45:25) :
This is stated in the usual nonsensical way. Of course, there is an effect. The question is how big the effect is. And it is very, very, very small, so it will have no measurable impact. One of the biggest flares ever gave a 267 parts per million [or 0.3 W/m2] increase in the total energy we got from the Sun at the maximum of the flare. And such superflares are very rare. Overall, the extra energy we get from flares is negligible.
I am not talking about a single superflare. Consider 234 flares, from which 38 were X flares, including one superflare, which were given during 1997 that produced a super-El Niño, for example. The following year, 1998, was the warmest year of the decade.
A single superflare as the one that you described would generate a change of temperature of 0.1 °C. Taking into account that the ocean stores energy and releases it very slowly, it is reasonable that more flare events would cause more warming of the oceans and, consequently, a larger fluctuation of the Earth’s temperature.
bill (04:07:13) :
Nasif Nahle (21:25:36): What heats up the Earth is the Sun and the change of temperature of the Earth is directly proportional to the load of heat incoming from the Sun
This statement is inaccurate (but approximate)
1. Taking the earth as a black body radiator as the earth heats it will non linearly lose more radiation.
2 As the earth heats More cloud / water vapour less ice etc will cause a non linear effect.
Solar radiation controls temperature but in a nonlinear complex manner.
Nasif Nahle (21:25:36): What heats up the Earth is the Sun and the change of temperature of the Earth is directly proportional to the load of heat incoming from the Sun
This statement is inaccurate (but approximate)
1. Taking the earth as a black body radiator as the earth heats it will non linearly lose more radiation.
2 As the earth heats More cloud / water vapour less ice etc will cause a non linear effect.
Solar radiation controls temperature but in a nonlinear complex manner.
You took only a fragment of my statement. Here the whole paragraph:
“What heats up the Earth is the Sun and the change of temperature of the Earth is directly proportional to the load of heat incoming from the Sun. If the Sun diminishes its output of energy, the load of energy received by the Earth would be lesser, etc.”
Is it inaccurate? Please, this is not the Bible from which you can cherry pick only those sentences and phrases that best suit to a homily.
In my response to Pamela I said:
“Yes, Pamela, that’s the argument here. Nobody is rejecting the idea on the existence of intrinsic and/or inherent factors which drive the climate of Earth. For example, the ocean acts as a thermoregulator.”
Have your doubts were satisfied?
Nasif Nahle (08:45:10) :
“What heats up the Earth is the Sun and the change of temperature of the Earth is directly proportional to the load of heat incoming from the Sun. If the Sun diminishes its output of energy, the load of energy received by the Earth would be lesser, etc.”
Is it inaccurate? Please, this is not the Bible from which you can cherry pick only those sentences and phrases that best suit to a homily.
Yes it is wildly inaccurate. The temperature of the Earth varies with the fourth root of the incoming heat. Double the heat and the temperature only goes up 19%. This is the reason that the effect of a change of TSI is so small.
Leif Svalgaard (09:38:22) :
Nasif Nahle (08:45:10) :
“What heats up the Earth is the Sun and the change of temperature of the Earth is directly proportional to the load of heat incoming from the Sun. If the Sun diminishes its output of energy, the load of energy received by the Earth would be lesser, etc.”
Is it inaccurate? Please, this is not the Bible from which you can cherry pick only those sentences and phrases that best suit to a homily.
Yes it is wildly inaccurate. The temperature of the Earth varies with the fourth root of the incoming heat. Double the heat and the temperature only goes up 19%. This is the reason that the effect of a change of TSI is so small.
However, it is directly proportional. If the incident solar irradiance upon the Earth’s surface goes up, the temperature of the surface goes up also. It would be inaccurate if the incident solar radiation striking on the Earth’s surface would go up and the temperature of the surface would go down. But not, it is directly proportional, even when there are intrinsic factors which could modify the effect.
Nasif Nahle (09:52:11) :
However, it is directly proportional.
Two quantities A and B are directly proportional if A = k B, so that if B doubles, A doubles as well. Since a T^4 = S [S-B’s law] T is not proportional to S.
Leif,
If I may comment.
T^4 = S is proportional, in this case exponentially proportional, not directly proportional. Unfortunately many people use proportional sloppily to mean if x rises when y rises, then x is proportional to y.
Leif Svalgaard (10:15:06) :
Two quantities A and B are directly proportional if A = k B, so that if B doubles, A doubles as well. Since a T^4 = S [S-B’s law] T is not proportional to S.
It is true for the proportionality between the intensity of the incident solar radiation on the surface and the temperature of the surface:
ΔΤ = λΔΦ
However, the intensity of the radiation from the surface is inversely proportional to its temperature:
k
Ћ = ———- (C) [(Gr) (Pr)]^a
D^3
k
Ћ = ———- (C) [(g β (Ts – T ∞) D^3 / v^2) (Pr)]^a
D^3
q = Ћ A (Ts – T∞)
Nasif Nahle (11:36:15) :
It is true for the proportionality between the intensity of the incident solar radiation on the surface and the temperature of the surface:
You are just digging yourself a bit deeper. The quantities are not proportional. For small changes, the changes are proportional.
However, the intensity of the radiation from the surface is inversely proportional to its temperature
Deeper still.
deathsinger (11:34:03) :
T^4 = S is proportional, in this case exponentially proportional,
Two quantities y and x are exponentially proportional if y = k^x. So T and S are not. Perhaps this will help
Leif Svalgaard (12:03:26) : Your comment is awaiting moderation
deathsinger (11:34:03) :
T^4 = S is proportional, in this case exponentially proportional,
Two quantities y and x are exponentially proportional if y = k^x. So T and S are not. Perhaps this will help
deathsinger (11:34:03) :
Leif,
If I may comment.
T^4 = S is proportional, in this case exponentially proportional, not directly proportional. Unfortunately many people use proportional sloppily to mean if x rises when y rises, then x is proportional to y.
Yes, you are right:
http://id.mind.net/~zona/mstm/physics/mechanics/forces/directProportion/directProportion.html
ΔΤ = λΔI is directly proportional; for example:
ΔΤ = (0.12) 0.3 W/m^2 = 0.036 K
And doubling ΔI:
ΔΤ = (0.12) 0.6 W/m^2 = 0.072 K
Or halving it:
ΔΤ = (0.12) 0.15 W/m^2 = 0.018 K
Correction: Add K/W m^-2 after 0.12.
Nasif Nahle (12:39:32) :
ΔΤ = λΔI is directly proportional
As I pointed out. But perhaps you were just being sloppy when you said that “the change of temperature of the Earth is directly proportional to the load of heat incoming from the Sun” and you meant ‘proportional to a [small] change of the heat incoming from the Sun’. I think that would have been the appropriate response rather than all your Greek symbols 🙂
Leif Svalgaard (13:01:45) :
As I pointed out. But perhaps you were just being sloppy when you said that “the change of temperature of the Earth is directly proportional to the load of heat incoming from the Sun” and you meant ‘proportional to a [small] change of the heat incoming from the Sun’. I think that would have been the appropriate response rather than all your Greek symbols 🙂
Ok, I made a careless use of language; it’s not easy for me to express my ideas in a foreign language and I use to drop or raise one or more words; thus it is easier for me to express my ideas through Greek symbols. 😉
I appreciate the discussion has moved on from where I left it on saturday morning, but thought I’d add this snippet. I just scaled off from the graph presented by the NOAA at their website which is pretty much the one calculated by Levitus et al 2009. It shows an increase in ocean heat content of around 5.5×10^22J between 1993 and 2003. During this time, the mean world sea level rose around 33mm according to satellite altimetry, and around half of that was due to thermal expansion according to IPCC estimates. (levitus is a lead IPCC author).
By my calculation, this amount of heat is only around half that required to get that expansion.
Either
1) The altimetry is wrong.
2) Only a 1/4 of the sea level rise was due to expansion and the ice caps melted more than estimated. (Unlikely)
3) Levitus et al have underestimated the amount of heat stored in the oceans by a factor of two.
Of interest is that Levitus et al only use the ocean temperature data to a depth of 720m. If (3) is correct I conclude that they have missed a lot of the extra heat stored at a deeper level in the ocean while the sun was on it’s strong run of cycles.
Also of interest is that Levitus et al 2000 had the rise in heat content for 1955 – 1994 around 13.7×10^22J, but this seems to have been halved in the most recent effort. Bob Tisdale informs me that this was due to a ‘warm bias correction in the XBT data’. If that older data was in fact correct and the 1993 – 2003 data should be adjusted up by a directly proportional amount, the books would balance and be consistent with an increase of around 0.3C in sea surface temperature over the same period.
Hmmm.
Re: bill (04:07:13)
As previously indicated, you can difference the series to see how they have imposed invariant seasonal structure upon the “data” (when you have time). CDIAC has a note at the bottom of their “data” files to alert people of the processing, but the articles to which they refer are not publicly available.
The diagnostics I described (from Stat 101) take only 2 minutes to complete. The lesson sinks in best when the exercise is conducted first-hand. When you have time, you will see that the residuals do not show random scatter (as they must in order for the model to be valid); rather, they show an exceptionally-systematic pattern (which is the most extreme model violation you can get).
Why is CDIAC presenting (badly) modeled-“data” instead of data? An analogy would be if before the sunspot numbers were released, they were all adjusted so that all solar cycles showed the exact same shape (but retained differing peak-amplitudes).
For anyone who studies phase relations & timescales other than 1 year, the preceding is of fundamental importance. (Based upon your various comments, you are restricting your view to the annual timescale and ignoring phase relations.) [Note: Don’t confuse timescale with resolution – for example, you can study hourly (resolution) data at the 17 month timescale.]
– –
Leif, you appear to be taking advantage of the general public’s failure to distinguish between linear relations and phase relations – capitalizing on this as an opportunity to drive a wedge between peoples’ common sense & their need for social harmony (achievable through conformity to your positions).
You leave the impression that your attitude is that since the general public is “never going to understand”, you are compelled to mislead (since you perceive yourself as advancing the lesser of 2 evils – not both of which can be avoided).
You are underestimating the audience.
– –
Re: woodfortrees (Paul Clark) (02:59:34)
Thanks for the comments on the woodfortrees “isolate” function – much appreciated.
May I ask for the story behind the name “woodfortrees”? This is of interest to me, in part, because I formally studied forestry & forest engineering and worked in forest research for a number of years. You’ve got me wondering if the development of the site had something to do with forest mensuration, biometry, &/or wood science.
Before addressing your other comments, I want to run some calculations and check some references (partly because I believe their procedure may be equivalent to another procedure I have seen used). For now I will note that while I do not suspect cherry picking, I do have concerns about the failure to include the 11a timescale summaries for comparison. [Ideally a multi-timescale color-contour plot would have been presented – among other benefits, this would have pre-empted “cherry picking” suspicions.]