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.
tallbloke (12:02:14) :
a decadal oscillation as it rises back to the surface and reinforces or or otherwise modulates the ocean’s response to the current solar cycle.
The temperature spike will be smeared out in time so you won’t get the same effect, and if the ‘response’ time is 5 years [as Schwartz thinks] or some number not equal to the cycle length, the effect would be a decrease in the oscillation. This whole thing cannot be handled with hand waving. One can make accurate models of this [I think this has been done – can’t remember where].
Leif Svalgaard (12:35:10) :
If I keep the heat on, the upper layers will not heat to any higher temperature, but the heat will penetrate deeper and deeper into the ocean [or the Earth (boreholes) for that matter]. Conversely, when you down down the heat, the heat already stored in the system will keep the temperature at the higher level for some time.
I’m glad we agree on this. According to the calculations I did the other day (I don’t just wave my hands) The 16mm of sea level increase due to expansion as opposed to melt etc between 1993 and 2003 has to be distributed down about 1000m on average. Because the thermocline in the tropics is at about 50m, this means the heat is stored much deeper elsewhere. For example, in the sea off Labrador, the thermocline is at around 2000m in the winter.
I’m well aware of the difference between heat and temperature, being an engineer by trade originally. The ocean has been heating since the late 60’s according to the ocean heat content graph in Levitus et al 2009, so this means the propagated heat raises the temperature of the deeper waters above the thermocline and was doing so for 40 years up until the ocean started cooling again in 2003.
when you turn down the heat, the heat already stored in the system will keep the temperature at the higher level for some time.
Swot I said innit? 🙂
After the weekend I’ll be getting the calculator hot working out the total joules stored, against the annual earth energy budget to get a handle on how long the cooling ocean might keep temps reasonable. My first back of the napkin estimate is just under two years unless the sun bucks up a bit. The residual heat further down will eke out more slowly but land surface temps and upper stratospheric temps will fall pretty quickly because the atmosphere loses lot’s to space, especially when the sea is cooling and there’s less evaporation to keep the good old greenhouse effect in top gear.
The temperature spike will be smeared out in time so you won’t get the same effect, and if the ‘response’ time is 5 years [as Schwartz thinks] or some number not equal to the cycle length, the effect would be a decrease in the oscillation.
I won’t try and argue this one now, because that would involve a lot of handwaving, but consider that water does stratify, and doesn’t mix readily below the turbulence zone. I can conceive of several mechanisms, being the son of a water engineer, but I’ll chew on it over the weekend while I watch the motorcycle racing at Knockhill. Anyway, it’s a side issue for me, the important bit is working out the size and wattage and current flow rate of the battery.
Thanks as always for your time.
woodfortrees (Paul Clark) (01:13:07) “running mean”
When I say “running mean” I mean to imply that my window’s left edge is _anchored at the beginning of the series while the window’s right-margin varies. When I say “moving average” I mean my averaging-window maintains constant width as it moves (i.e. the window’s left-margin is not anchored). In the former case I plot values at window-right; in the latter case I plot at the window-midpoint. (Note: There are context-specific variants.)
The preceding may seem a trivial point — the reason I mention it is that it is so often necessary to infer from context which way “running mean” is being used …since most people do not make the distinction – i.e. they just say “running mean” regardless of the scenario.
Of course conventions vary – so one really does need to infer from context what is meant.
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Paul, you have a great website. Question: Can you explain what “isolate” does? I looked around on the woodfortrees links one day but could not find explanations for some of the drop-down-menu functions.
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I see Leif already pointed out that Le Mouel, Courtillot, Blanter, & Shnirman used a geomagnetic index. Your question about why you do not get their curve prompted me to review more-carefully what they did:
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.
I’ve performed the calculation at monthly resolution for aa, Log2(aa), & Sqrt(aa) — the curves share (roughly) some features with the blue (geomagnetic) curves in the article, but not all features – so when I have some free time, I might:
1) do the same calculations for daily aa
2) look into their reference [12]
3) hunt for the Eskdalemuir geomagnetic series.
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Leif Svalgaard (06:30:42) “One solution to this would be to require that the reviews [all of them, from the first journal to the last that finally accepted the paper] be public and be [electronically] attached to the paper. We are not there yet, but it would be a great help in judging the trustworthiness of the paper.”
For a whole lot of (good) reasons you’re going to have a tough-sell with this idea.
I’ll state my preference again: A liberal publication system in conjunction with a much better education system. With a higher rate of science-literacy & numeracy, we wouldn’t have to worry so much about judgement capacity. People would be empowered to see what other (perhaps more creative) people did (perhaps wrong) …and then go do better. The best stuff would float to the top – fast.
In any event: It will be interesting to see how the system evolves to better-match the online medium’s potential.
The Chandler wobble period plummeted from ~1921 until ~1942. The phase reversal was in ~1931 and can be linked (statistically – I’m still waiting for a physicist to explain the mechanism) to a very unique combination of the following: (1) terrestrial polar motion, (2) solar system dynamics, & (3) the lunar nodal cycle. The alignment is precise and unique in the entire polar motion record (1846-present) – i.e. there is no other such spike.
With awareness of this, some of you should be able to pull several threads together (e.g. precipitation, length of day, polar motion, atmospheric angular momentum, SOI, NAO, solar variation, temperature [global, regional, minimum, maximum, average, extreme monthly minimum, & extreme monthly maximum], rate of change of carbon dioxide concentration, …)
Leif,
Your idea is a constructive idea in regards to the peer-review process.
If I understand your comment: Complete disclosure.
No secrecy, in the reviewing process. All reviewers must be identified.
Sunshine is the best disinfectant.
Merit is the answer to the current difficulties, not continued secrecy.
With awareness of this, some of you should be able to pull several threads together (e.g. precipitation, length of day, polar motion, atmospheric angular momentum, SOI, NAO, solar variation, temperature [global, regional, minimum, maximum, average, extreme monthly minimum, & extreme monthly maximum], rate of change of carbon dioxide concentration, …)
Sounds like a piece of cake. I notice you are saying other people should do it though. 😉
Interesting post. Thanks.
Another thought on why the thermocline is deeper away from the tropics. Warm water spreads from the tropics polewards in wind driven currents. Due to the greater evaporation rates in the tropics, it’s a good deal saltier than the water it’s moving into. Even though it’s warmer, it will be denser than the cooler extra-tropical water and will sink. Need to check some real world figures, but 20C water at 39,000 mg/m3 is denser than 10C water at 35000mg/m3 by 1kg/m3.
Right, off to Bonnie Scotland.
tallbloke (23:21:38) “Sounds like a piece of cake. I notice you are saying other people should do it though. ;-)”
Clarification:
I’ve done the preliminary analyses.
Re: James F. Evans (22:53:08)
The suggested system is administratively extreme. The resistance would succeed – it would spill around the barriers like an uncontainable wave. The response would be “blue ribbon panels” popping up like dandelions.
On the other hand, some small modifications might be well-received – and perhaps ongoing diversification is feasible.
Paul Vaughan (02:04:12) :
were you the person I was conversing with on an old thread about CO2 and what causes the sudden dip (still no plausible answer by the way!!!!).
The final statements you made concerned inaccuracies you uncovered in the CO2 records. I was going to reply but the thread became old and you might have missed it
Anyway here is my comparison of Barrow data when sampled Monthly and “hourly” – all flagged errors have been removed from the hourly data.
http://img13.imageshack.us/img13/2339/co2barrowhourvsmonthobs.jpg
The only errors I can see are that the hourly data is offset by +2 weeks from the monthly. Is that the complaint to which you refered?
This is the plot that sparked my query – “what causes the sudden dip in CO2 that dominates the globe including half the southern hemisphere, and why does it occur within a cople of monts from barrow to christmas island?”
http://img527.imageshack.us/img527/6153/co2manysitesch4.jpg
Paul Vaughan (17:26:09) :
3) hunt for the Eskdalemuir geomagnetic series.
here: http://swdcwww.kugi.kyoto-u.ac.jp/hyplt/index.html
but why use ESK which is known to have data problem?
tallbloke (08:32:30) “If you want to see the solar signal in the temperature series just smooth the temp series on a 43 month moving average […]”
Leif Svalgaard (08:48:45) “[…] the signal in your graph disappears when you just go a bit further back, e.g. to 1880.”
bill (09:06:23) “43 months – why? […] wonderful cherry orchard!”
tallbloke (09:24:51) “1910 on is more reliable SST data IMO. 43 months because that is 1/3 of the solar cycle.”
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It may not have been evident, but my post at Paul Vaughan (18:11:23) [July 3, 2009] relates to the preceding quotes.
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When one takes the harmonics of polar motion into account in analyses, whole arrays of phase relations crystallize.
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Some would justify 43 month bandwidth as enough to suppress (some of) ENSO-related – or simply interannual – variation. 39 month time-integration can be theoretically justified by noting the beat period of the annual & Chandler wobbles – & working out the harmonics.
Clarification:
39 months on average — keep in mind that we’re dealing with nonstationary signals [which is why we can’t stop at basic FFT].
For deeper insight – Step 1:
Maximize the modulus of a Morlet (wavenumber = 2pi) complex wavelet transform of the magnitude of the gradient of the 2-dimensional (x,y) polar motion vector in the time-domain.
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Once one takes the Chandler wobble reversal into account, the simplicity of previously-perplexing phase relations begins crystallizing.
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For example, you should immediately see a problem with Leif’s claim (quoted above) as soon as you handle 1931 plus/minus a decade according to its unique conditions. You can create what statisticians call a “conditioning variable” – or what electrical engineers call a “switch”. (Note: You’ll actually need at least 2 switches.)
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Everyone should read the following book – & for every detail:
William S. Cleveland (1993). Visualizing Data.
http://www.stat.purdue.edu/~wsc/visualizing.html
Pay attention, in particular, to everything about coplots (short for conditioning plot) if you want to enhance your ability to disentangle complexity – via conditioning.
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Noteworthy:
1931 is dead-centre in Dr. Ivanka Charvatova’s trefoil window 1906-1956.
If one uses cross-wavelet acoustic analysis, one will find 1:2:3 resonance broken at 1931 and nowhere else during the polar motion record.
If anyone knows an open-minded astrophysicist who would be willing to patiently & respectfully help me work on the (physical) mechanics of this unique disruption of terrestrial phase relations (which can be precisely documented quantitatively via cross-wavelet acoustic analysis), please let me know. Statistical reasoning suggests this to be a MAJOR clue about the terrestrial hydrologic cycle.
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Once again:
Strongly recommended reading:
Jan Vondrak (1999). Earth rotation parameters 1899.7-1992.0 after reanalysis within the hipparcos frame. Surveys in Geophysics 20, 169-195.
http://www.yspu.yar.ru/astronomy/lib/Rotation.pdf
[See particularly section 3.2.]
J. Vondrak & C. Ron (2005). The great Chandler wobble change in 1923-1940 re-visited. In: H.-P. Plag, B. Chao, R. Gross, & T. Van Dam (eds.), Forcing of polar motion in the Chandler frequency band: A contribution to understanding interannual climate variations, Cahiers du Centre Europeen de Geodynamique et de Seismologie 24, 39-47.
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Also:
1) N.S. Sidorenkov (2005). Physics of the Earth’s rotation instabilities. Astronomical and Astrophysical Transactions 24(5), 425-439.
http://images.astronet.ru/pubd/2008/09/28/0001230882/425-439.pdf
[See particularly the “thermal engine” conceptual framework laid out in section 2.]
2) W. Kosek (2005). Excitation of the Chandler wobble by the geophysical annual cycle.
http://www.cbk.waw.pl/~kosek/s11/LxPcorr_kosek.pdf
3) Harald Schmitz-Hubsch & Harald Schuh (1999). Seasonal and short-period fluctuations of Earth rotation investigated by wavelet analysis. Technical Report 1999.6-2 Department of Geodesy & Geoinformatics, Stuttgart University, p.421-432.
http://www.uni-stuttgart.de/gi/research/schriftenreihe/quo_vadis/pdf/schmitzhuebsch.pdf
4) Y.H. Zhou, D.W. Zheng, & X.H. Liao (2001). Wavelet analysis of interannual LOD, AAM, and ENSO: 1997-98 El Nino and 1998-99 La Nina signals. Journal of Geodesy 75, 164-168.
5) Gross, R. S. (2005). The observed period and Q of the Chandler wobble. In: H.-P. Plag, B. Chao, R. Gross, & T. Van Dam (eds.), Forcing of polar motion in the Chandler frequency band: A contribution to understanding interannual climate variations, Cahiers du Centre Europeen de Geodynamique et de Seismologie 24, 31-37.
http://www.sbl.statkart.no/literature/plag_etal_2005_editors/gross_1_CWTQ_final.pdf
Leif Svalgaard (12:48:42) “but why use ESK which is known to have data problem?”
Mainly to verify the curves – & be absolutely certain about how moving-windows were centred. Elaboration: Whenever possible, I reproduce calculations presented in papers. I imagine you will agree that the awareness arising from such exercises is (generally) valuable. [Furthermore, once the algorithm is built, it can easily be applied to series without quality issues.]
Btw: Thanks for the upthread note about ESK series quality.
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Re: bill (04:24:13)
The consistent winter dips in the rate of change of CDIAC’s Alert, Nunavut, Canada CO2 time series are PURELY ARTIFICIAL.
The CDIAC CO2 “data” are NOT data.
(See the print UNDER their “data”.)
Based on my present knowledge, I remain willing to use the NOAA CO2 data in any analyses I run, but the CDIAC “data” is useless to a careful & responsible analyst (who has a better alternative). [A careless &/or irresponsible analyst might fail or choose to fail to: (a) venture from the annual timescale & (b) consider rates of change.]
CDIAC CO2 “data“:
http://cdiac.ornl.gov/trends/co2/sio-keel.html
NOAA CO2 data:
ftp://ftp.cmdl.noaa.gov/ccg/co2/
Have you tried the diagnostic exercise I suggested in the earlier thread? (If you do, you might laugh out loud when you see the residuals plot.)
As for your question: You have to keep in mind that not every global-scale terrestrial process with a north-south dimension is distributed symmetrically about the equator. (This is exactly the kind of crippling assumption that builds lengthy delays into our learning. We have a serious cultural-learning problem in our society: People have been conditioned to put more faith in models than in observations. The recent economic crash should be a wake-up call.)
Paul Vaughan (16:56:10) :
Statistical reasoning suggests this to be a MAJOR clue about the terrestrial hydrologic cycle.
When a relationship does not bear out or hold up, it is physical reasoning suggests that it was spurious to begin with.
Re: Leif Svalgaard (20:23:30)
No reasonable person will be doubting a link with the hydrologic cycle Leif.
Paul Vaughan (23:25:34) :
No reasonable person will be doubting a link with the hydrologic cycle
This reasonable person doubts very much a link with the hydrological cycle and the trefoil pattern.
Thanks Leif Svalgaard, Paul Vaughn, tallbloke. Anthony, discussions/debates like these on your blog prove the truth of a Fourth of July “freedom” celebration. What a unique experience this is — along with that provided by a number of your colleagues elsewhere. And this grateful non-scientist has lots more reading for the “idle” hours.
@Paul Vaughan… Oh, Paul! Haven’t you realized that the Sun is a small torch oil-painted on a crystal sphere in the sky and has nothing to do with anything is happening on Earth? Welcome to wonderland! 🙂
Leif Svalgaard (04:20:00) “This reasonable person doubts very much a link with the hydrological cycle and the trefoil pattern.”
This is how rumors get started – people twist other peoples’ words.
Re: Nasif Nahle (09:25:58)
One begins to wonder if ‘global’ security somehow depends on Leif’s ability to keep the general public believing in Santa Claus.
Paul Vaughan (10:25:37) :
This is how rumors get started – people twist other peoples’ words.
Twisting is aided by vagueness. Perhaps you could clarify precisely what is supposed to linked with what…
Also, when asked to reply to straight questions, squirming to avoid a straight answer doesn’t help your cause. Let me try again:
Please tell me what Charvatova’s ‘central thesis’ was that I missed to take into account, and why it should have been taken into account.
Leif Svalgaard (11:55:50) “[…] when asked to reply to straight questions, squirming to avoid a straight answer doesn’t help your cause.”
Appropriate response is not always a straightforward reply. (It is unwise to take partisan-bait.)
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Leif Svalgaard (11:55:50) “Perhaps you could clarify precisely what is supposed to linked with what…”
In increments perhaps.
To get started:
Does temperature (or temperature range) affect geomagnetic indices?
Increasing the pace:
Do you think it is reasonable to claim that the Chandler wobble phase reversal does NOT show up in the aa index record?
The Sun heats the planet and we know by how much. Without it we would be colder. Much colder. Anyone who argues that the Sun has nothing to do with our climate is crazy. I would not say such a thing. Leif would not say such a thing. Leif and all the other scientists I have read know how the Sun heats the planet and know how the slight variation in the Sun changes how much it slightly changes its capacity to heat the planet. None of that is arguable. To try to make it an argument speaks volumes about the poster who engages in such diversion nonsense. 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.
Paul Vaughan (14:54:05) :
Appropriate response is not always a straightforward reply. (It is unwise to take partisan-bait.)
But it is simple human decency [to the extent you have it, of course – one cannot ask what you cannot give] to give a straight and honest answer.
Does temperature (or temperature range) affect geomagnetic indices?
Do you think it is reasonable to claim that the Chandler wobble phase reversal does NOT show up in the aa index record?
If you think you have something to say, say it directly. If you have some mechanism to peddle, do that in a straightforward way without circumspection. My answer to both your questions would be a resounding ‘no’ to the first and ‘yes’ to the second. But you are not after my answers per se. If you disagree with them, explain why and provide solid evidence [many of the papers you have cited do not contain evidence, but speculations].
And for the first question, you really have to specify temperature where? and define ‘range’ [e.g. on what time scale]. For example, the temperature of the magnet with which we measure the geomagnetic index does influence the index, as the response of the magnet depends on its magnetic moment which depends on the length on the magnet which depends on its temperature [warmer = longer].