Guest essay by Stan Robertson
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In a recent post entitled “Changes in Total Solar Irradiance” (http://wattsupwiththat.com/2014/10/25/changes-in-total-solar-irradiance/ ), Willis Eschenbach showed a plot of the solar irradiance that impinges at the top of the earth’s atmosphere. I have borrowed that from his post and repeat it here for convenience:
Fig. 1 Variations of TSI
Willis asked a profound question about these results:
“If the tiny eleven-year changes in TSI of a quarter of a W/m2 cause an observable change in the temperature, then where is the effect of the ~ 22 W/m2 annual variation in the amount of sun hitting the earth? That annual change is a hundred times the size of the eleven-year TSI change. Where is the effect of that 22 W/m2 change?”
This is a great question, but it is really two questions. First, why don’t we see some significant annual cyclic variation of global mean temperature? This is a truly profound question! It ought to keep climate modelers awake all night, every night. Second, if 22 W/m2 variations peak to trough don’t produce noticeable temperature variations, why should the 0.25 W/m2 variations of TSI associated with solar cycles produce any measurable temperature variations?
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Let’s take the first question first. TSI reaches a peak on January 3 when we are nearest the sun and drops to a minimum six months later. Now 22 W/m2 is comparable to the change of TSI at 60 degrees north or south latitudes between ice ages and interglacial times. On this basis, one might expect to see a fairly substantial annual cyclic variation in global mean temperature. I failed to recall any in the many plots of global temperature anomalies that I have seen, but thought perhaps that single years wouldn’t stand out clearly in long, noisy records. So I grabbed a quick ten year data plot that I happened to have on hand to see if it showed annual cycles. None were obvious, but just to be sure, I took another look at the (also-quickly-available) periodogram for sea surface temperatures that I had made for a previous WUWT article (http://wattsupwiththat.com/2014/07/26/solar-cycle-driven-ocean-temperature-variations.) Not only is there no significant temperature variation with a one year period, there IS a small amplitude oscillation (0.13 oC peak to trough, 2X amplitude) at the 11 year solar cycle period with oscillation peaks that are nicely in phase with the sunspot peaks.
Fig. 2. Amplitude Periodogram of sea surface temperature anomalies 1954 – 2014
One of the first suggested explanations for the lack of annual cycles that I recall was that the variations might occur too fast for the earth mean temperature to respond. Considering that temperatures of either the northern or southern hemispheres of earth respond dramatically on a seasonal time scale to changes of solar flux at the surface, this seemed unlikely to me. Nevertheless, I dusted off my old computer program for calculating ocean surface temperature changes for changes of impinging solar flux. Previous calculation results have been reported here: (http://wattsupwiththat.com/2013/10/10/the-sun-does-it-now-go-figure-out-how) and here: http://wattsupwiththat.com/2014/07/26/solar-cycle-driven-ocean-temperature-variations
In the first of these, I found that a thermal diffusivity of 1 cm2/s for upper ocean waters was needed to account for the ocean surface temperatures (HadSST3gl) and ocean heat content measurements since 1965. If there were no changes of cloud cover or evaporation, 70% of that 22 W/m2 or 15 W/m2 would enter the atmosphere. If it impinged on oceans, it would drive annual temperature variation of 0.45 oC peak to trough. The temperature oscillations would, indeed, be larger if the solar flux variations occurred over a longer time. With a ten year period, they would produce temperature oscillations of 2.25 oC. In either case, most of the variations of the peak heat flux would be taken into the oceans and eventually returned later. Nevertheless, annual oscillations of 0.45 oC ought to stick out like a sore thumb in Fig. 2. So why don’t they occur? The only plausible explanation is that increases of cloud cover prevent most of that 22 W/m2 variation from ever reaching the surface. If absorbed by atmosphere, land or ocean, large temperature changes would necessarily follow. The minimum temperature increases would be those of the oceans, due to their transparency and large heat capacity. But they don’t show!
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We can make this a little more quantitative to show that there is reason to believe that most of the TSI variations are negated by changes of cloud cover. The variations of cloud cover should correspond to variations of the atmospheric water column, as shown here in this plot from http://www.climate4you.com .
Fig 3. Atmospheric water vapor column (thickness if subjected to 1 atm pressure)
The total water column varies annually by about 0.45 cm peak to trough, for about 19% annual variation. Taken as a sinusoidal oscillation, its peak to trough variation would be 0.45 cm and its rate of change would have a peak to trough variation of (2 π 0.45 cm/yr). This rate of change would need to be provided by the solar flux that evaporates water at the earth’s surface. It takes about 2260 joules per gram to evaporate water. Then neglecting the minor amount of energy needed to lift the water vapor up into the atmosphere, the peak to trough rate of energy change needed for evaporation at the earth surface would then be:
(2 π 0.45 cm/yr) x (1 gm/cm3 x ( 2260 j / gm) x (1 yr / (365 x 86400 s)) x 104 cm2/m2 = 2 W/m2
This shows that very little of the available TSI variation is needed to produce the annual changes of atmospheric water column and, presumably, the variation of cloud cover. But if earth albedo changes in proportion to the variation of the atmospheric water column, then reflected solar radiation would vary by 19% of the mean 101 W/m2, or 19 W/m2. That would leave only about 3 W/m2 of the 22 W/m2 of TSI variation available to heat the earth surface. Since about 2 W/m2 is needed to produce evaporation, that leaves only about 1 W/m2 to be absorbed and warm the surface. Using the same computer program that I mentioned previously, I calculated that 1.0 W/m2 annual variations at the ocean surfaces would produce surface temperature oscillations of about 0.037 oC peak to trough. This is too little to be reliably extracted from noisy sea surface temperature data, but this is about what is shown in Figure 2.
A careful examination of Fig. 3 shows that the water column peaks seem to occur about late October rather than Jan. 3. The early peak is thought to be due to the end of the vegetation growth season in the northern hemisphere. The larger land mass of the northern hemisphere allows it to contribute more to evaporation during its growth season than does the southern hemisphere. This puts the annual TSI variation and cloud cover variation slightly out of phase but that really doesn’t matter much as long as there is enough extra cloud in January to negate the peak TSI. Another point worth noting about Fig. 3 is the step change downward after the 1998 El Nino. Prior to that, the water column was increasing, presumably because of surface warming and increasing evaporation. The smaller water column since 1998 is consistent with some cooling and the flat global temperatures of this century.
The most significant result of the preceding analysis is that it is clear that evaporation of water vapor into the atmosphere and cloud formation must provide a very strong negative feedback to radiative forcing in the UV/Vis bands that deliver most of the solar energy to earth. Starting from the present near-equilibrium conditions, a decrease of albedo would let more solar radiation reach the surface of the earth. That should be able to evaporate more water, produce more clouds and raise the albedo. If the albedo were to increase a bit beyond equilibrium, the surface would receive less insolation, the upper oceans would cool and cloud cover would decrease until balance was restored. Considering that downwelling infrared radiation is absorbed essentially at the ocean surfaces, the only thing that it can do is produce evaporation. We have just seen that a radiative forcing of 22 W/m2 apparently produces only a few hundredths of a degree of ocean surface temperature change. It seems a bit absurd to think that the 3.7 W/m2 of IR forcing that is expected to accompany a doubling of the atmospheric concentration of CO2 might do more. CO2 is simply not the control knob for the earth’s temperature.
Since cloud cover is so exquisitely regulated that it maintains a steady mean temperature, it would appear to be necessary for climate models to handle clouds well. In fact, however, that is one of their weaknesses. In general, the models used by the IPCC do a miserable job of modeling rainfall. It is highly likely that they are doing an equally poor job of cloud cover and albedo. Until this situation is dramatically improved, the climate models will remain essentially useless for anything but scare tactics.
Moving on to Willis’ implied question: If 22 W/m2 produces no significant temperature variations, why should the 0.25 W/m2 associated with the approximately 11 year solar cycles have the larger effect shown in Fig. 2? Only about half of this small amount would even reach ground level anyway. So how is it that we see 11 year solar cycle period temperature variability in the 60 year sea surface temperature record of Fig. 2? There are several possible explanations here. Some folks claim that the solar cycle temperature oscillations are spurious, but that seems unlikely to me for several reasons. First, the temperature peaks match the sunspot peaks. Second, I showed that Willis’ slow Fourier transform technique is quite capable of pulling this small signal out of the noisy data. Additionally, Roy Spencer, Nir Shaviv and others have found temperature variations of similar magnitude using different methods and data sets. Leif Svalgaard thinks that ~ 0.1oC temperature variations are real; however, he mistakenly persists in thinking that TSI variations of order 0.1 W/m2 at the earth surface can cause such temperature changes in several tens of meters of upper oceans. (Bear in mind that the first 25 meters of ocean has about 10X the heat capacity of the entire atmosphere.) Others claim that the temperature variations are spurious due to significant volcanic eruptions having occurred with approximate solar cycle timing. I think this to be very unlikely on a 60 year data set.
So, let’s take the question and the result of Fig. 2 seriously for a moment. The TSI variations associated with the solar cycle are only about 0.25 W/m 2, averaged over the earth surface and daily cycles. About 70%, or 0.175 W/m2 enters the troposphere. About (160/340)x0.25W/m2 = 0.117 W/m2 reaches the surface at wavelengths below 2 micron. About half the difference between the 0.175 and 0.117 W/m2 reaches the surface at longer wavelengths and after scattering in the atmosphere. This gives a peak to trough variation of about 0.15 W/m2 that would reach the surface. This is only about 15% of the 1.0 W/m2 that would be needed to drive surface temperature oscillations of 0.13 oC. So without even considering the possibility that changes of albedo might prevent most of the solar flux variation from even reaching the earth, it is apparent that TSI variations associated with the solar cycle do not provide enough energy to produce the temperature oscillations shown in Fig. 2.
To make it even more certain that the TSI variations are not the direct cause of the surface temperature oscillations, recall that albedo variations of about 19% were sufficient to negate the 22 W/m2 annual TSI variation and that this required only about 2 W/m2 to evaporate the water. One would therefore expect that about one could negate 0.25 W/m2 variations with about (0.25/22)x2 = 0.023W/m2. This is only about 15% of the 0.15 W/m2, 11 year, TSI variation that would occur at ground level if there were no albedo change. So even though the TSI variations would be too small to produce the observed surface temperature changes, they should easily evaporate enough water for a nullifying negative feedback. So the tiny variations of TSI associated with the solar cycle should be just as effectively negated as the 22 W/m2 of the annual cycle. This leaves a very stark question: If the temperature oscillations of Fig. 2 at the 11 year period are real and if they are produced by the sun, then how could the sun do it?
To answer this we need to consider another point made by Willis Eschenbach here: http://wattsupwiththat.com/2013/12/28/the-thermostatic-throttle/ . He showed that the evaporative feedback that regulates Earth’s albedo and temperature functions most strongly near the equator. Oceans areas near the poles show the reverse behavior. Tropical albedo changes cool the tropics, but near the poles the albedo decreases with increasing temperatures. This has the effect of making the equatorial zone cooler than it would be otherwise, while making the poles warmer. There seems to be less of either positive or negative feedback in mid-latitudes. This is what allows volcanic eruptions and other atmospheric disturbances outside the equatorial regions to affect surface temperatures. If the sun contributes something other than the dinky TSI changes over solar cycles, and outside the equatorial zone, then it might be able to produce the oscillations shown in Fig. 2.
It is well known that large volcanic eruptions can cool the earth. Volcanic ash shades the earth and produces short term cooling, but the most significant and longer lasting effects occur due to aerosols. The USGS (http://volcanoes.usgs.gov/hazards/gas/climate.php) says: The most significant climate impacts from volcanic injections into the stratosphere come from the conversion of sulfur dioxide to sulfuric acid, which condenses rapidly in the stratosphere to form fine sulfate aerosols. [Cloud droplets grown on] the aerosols increase the reflection of radiation from the Sun back into space, cooling the Earth’s lower atmosphere or troposphere. Several eruptions during the past century have caused a decline in the average temperature at the Earth’s surface of up to half a degree (Fahrenheit scale) for periods of one to three years. The climactic eruption of Mount Pinatubo on June 15, 1991, was one of the largest eruptions of the twentieth century and injected a 20-million ton (metric scale) sulfur dioxide cloud into the stratosphere at an altitude of more than 20 miles. The Pinatubo cloud was the largest sulfur dioxide cloud ever observed in the stratosphere since the beginning of such observations by satellites in 1978. It caused what is believed to be the largest aerosol disturbance of the stratosphere in the twentieth century, though probably smaller than the disturbances from eruptions of Krakatau in 1883 and Tambora in 1815. Consequently, it was a standout in its climate impact and cooled the Earth’s surface for three years following the eruption, by as much as 1.3 degrees at the height of the impact. Sulfur dioxide from the large 1783-1784 Laki fissure eruption in Iceland caused regional cooling of Europe and North America by similar amounts for similar periods of time.
These comments show that naturally occurring variations of aerosols are capable of producing surface insolation changes that are NOT entirely killed by negative feedback.
As long-time WUWT readers are aware, the Danish researcher, Henrik Svensmark, in 1996 proposed that cosmic rays that enter the atmosphere can produce aerosol condensation nuclei. The flux of cosmic rays is modulated by the strength of the sun’s magnetic field that reaches the earth and this varies with the nominal 11 year solar cycle. Fewer cosmic rays reach earth at the solar cycle peaks than at minima. This has been confirmed by direct measurements of cosmic ray flux over several solar cycles. Recent studies also seem to confirm that condensation nuclei can be produced by cosmic rays. See, e.g., http://www.youtube.com/watch?v=sDo7saKaEys .
What remains to be seen is whether the amounts of cosmic ray produced condensation nuclei and their variations are capable of significantly modulating the amount and reflectivity of cloud cover. This should be settled by measurements within the next decade or two. It would take very little change of cloud cover to produce the 0.13 oC peak to trough temperature oscillations at the 11 year period shown in Fig. 2. In the WUWT article in which I first used Fig. 2, I showed that it would take peak to trough variation of solar flux of about 1 W/m2, averaged over the sea surfaces to produce this temperature oscillation. This solar magnetic field effect would presumably occur over all latitudes from poles to equator. It would need to produce an average of about 1% change of cloud reflectivity, which presently reflects about 100 W/m2 of the average TSI at the earth.
Conclusions: The feedback that negates the effect of 22 W/m2 should be of huge concern to climate modelers. The amounts, types, both vertical and horizontal distributions and albedo of clouds need to be accurately modeled in order to determine the patterns of surface temperature on the earth. In these regards, I think that the present models used by the IPCC are inadequate, misleading and lacking in any ability to predict global mean temperatures for the future.
Whatever one might think to be the cause of the temperature oscillations shown in Fig. 2 at the nominal 11 year solar cycle period, it should be very clear that the TSI variations over a solar cycle are completely incapable of producing them. If the sun really is responsible for producing those small temperature changes, then Svensmark’s cosmic ray modulation theory would seem to be our best hope for understanding how it does it. Think of the cosmic ray modulation as a small amount of jiggling of the earth’s cloud thermostat. About one percent modulation of cloud albedo over a nominal 11 year solar cycle is all that is required.
Or maybe I should just say:
I’ve looked at clouds from both sides now
From up and down and still somehow
It’s cloud’s illusions I recall
I really don’t know clouds at all
Biographical Note: Stan Robertson, Ph.D, P.E., is a physicist, retired from Southwestern Oklahoma State University.
TLM: His whole essay is based on this premise which is demonstrably false. As stated several times in the comments, there IS a “significant annual cyclic variation of global mean temperature” so the arguments he puts forward that the global temperature is almost completely insensitive to TSI because of this so called “fact” collapses and his conclusion immediately loses about 90% of its support.
Where is this significant annual cycling variation in global mean temp presented?
Edim has a graph earlier in the comments:
http://wattsupwiththat.com/2014/11/11/cloud-feedback/#comment-1786361
The global average temperature cycles about 4c between July and January each year. Stan’s assumption of no change was based on temperature “variance” which compares the day being measured with the average of the same day’s temperature in previous years. If it is 16c on 1st July 2014 and the average temperature for July is 16c then the variance is zero. If the temperature on every day is always exactly the average for that day, then the variance for every day of the year will be zero despite the fact that the globe was 4c warmer in July than it was in January.
Draw a graph of the absolute temperatures and it will show the neat sine wave shown in Edim’s post. Draw a graph of the temperature variance outlined above and it will be a flat line on zero, the same flat line that prompted Stan to comment that there was no “significant annual cycling variation in global mean temp”. He was just plain wrong and it is difficult to extract anything meaningful from his essay when you understand that point.
In fact the 4c change is actually the result of counteracting rises and falls in the temperature of each hemisphere. The northern hemisphere experiences a rise and fall range of around 13c due to a change in solar insolation due to the tilt of the earth. We call this affect the “seasons” (you may have heard of this) whereby Solar Insolation increases during the Summer and reduces during the Winter. If the Earth was insensitive to changes in solar insolation in the way that Stan proposes, then we would not have seasons.
I could be more rude about Stan, but he is clearly a very intelligent guy and we all make mistakes.
TLM, Thanks. This is something I keep forgetting. I ought to have read all of the comments before writing mine.
“Recent studies also seem to confirm that condensation nuclei can be produced by cosmic rays.”
This was demonstrated a hundred years ago by C.T.R. Wilson of the Wilson Cloud Chamber. I guess I’m showing my age. No one seems to cite this pioneer anymore – it was a topic in physics taught in the 1950s and earlier. Wilson won the Nobel Prize for this demonstration. Not just cosmic rays have this effect, but electrons, and other subatomic particles. Possibly we should investigate other particles that also invade our atmosphere or break up atmospheric atoms into such particles. I hope Svensmark duly cited CTRW.
‘The only plausible explanation is that increases of cloud cover prevent most of that 22 W/m2 variation from ever reaching the surface.’
There is the elephant in the room. Not even the seasons show up in the data. http://www.woodfortrees.org/plot/hadcrut4nh/from:2005/to:2010/mean:3/plot/hadcrut4sh/from:2005/to:2010/mean:3
Oh dear. Not another one.
Wake up Rob, read the rest of the thread before you post. HadCrut4 is an index of temperature Variance not absolute temperatures!
The whole point of using variance is to remove the seasonal effect!
I get it. Just making the same point as above.
Not a fantastic correlation between the difference in RSS and RSS (land only) and TSI minus seasonal but it looks interesting . Land temperatures should lag as the oceans warm (late 1990s) and cloud cover might be important.
Sorry but I don’t have the time at the moment to put up a plot.
Why dose climate science shy away from this ? http://books.google.com.au/books?id=0hzDN81ei5cC&pg=PA173&lpg=PA173&dq=atmospheric+heat+electrons+and+microwaves&source=bl&ots=cLRLKS7Wsq&sig=1yhQcbzhihVjII2TrivMfcVTIio&hl=en&sa=X&ei=8LhjVPSdJqXLmwXAg4CABw&ved=0CDcQ6AEwBw#v=onepage&q=atmospheric%20heat%20electrons%20and%20microwaves&f=false
Very interesting.
As you are looking at what is essentially a hemispheric phenomena – annual variation in TSI – analysis of the data by hemisphere (and by latitudinal bands) would be more informative than global averages.
For example, to what extent does the SH sea ice peak extent in late September affect the WV column peak in October? I suspect they are not unrelated.
My reason for thinking this, is that to the north of the SH sea ice at maximum is essentially continuous ocean. Whereas, to the south of NH sea ice at maximum, land area is at it’s maximum extent relative to ocean area – roughly 75% land.
Therefore one would expect much greater ocean evaporation in September/October in the SH, compared to March/April in the NH. Also air/sea surface temperature differentials are greater in the SH.
Great post – and comments. Many of us probably did not realise the global temp time series we’re used to seeing is a residuals plot with the annual signal removed. We all make mistakes.
Nevertheless, this annual variation in TSI holds the key to understanding the checks and balances of the climate system. A massive 22 W/m2 amplitude provides an annual test of all feed-backs and amplifications, instead of waiting around 80 years for the CO2 to double. There is some annual cloud variation too, but second place for annual variation in the climate system goes to the all-important green house gas: water vapor. Water vapor peaks in Sep-Oct, and has a trough in Feb-Mar. The amplitude is ~19%, providing a green house gas forcing that dwarfs any change in CO2 forcing we’ll ever experience. Without water vapor, Earth would be like Antarctica everywhere, so a 19% annual amplitude is pretty dramatic.
I wonder if the current orbit of the planet placed us nearest the Sun in northern summer instead of in January, would we see a scorching hot northern hemisphere in summertime. Amplified by i) proximity to the sun, ii) peak water vapor in September, and iii) more land area in the north. This of course happens regularly with some several 1000-year interval. Perhaps some paleoclimate has the answer to this. Or does the water vapor somehow balance the TSI variation instead of amplifying it. If you plot TSI and water vapor together, they are in opposite phase with 1-2 months lag time.
K.Almholt: Thanks for making the point that the annual variations give us an annual test of feedbacks and amplifications. I may have screwed up this analysis by failing to realize that annual variations had been removed from the records, but you are entirely correct and it is an important point. We ought to be seeing analyses that take advantage of a big annual effect to sort out what is radiatively important and what is not.
bones commented
I have been doing this 🙂
You can see this here
http://www.science20.com/virtual_worlds
and lots of data can be found at the url in my name.
err, “bones” = Stan Robertson ??!
That’s a couple of replies that give me that impression. If that is the case, it would make a lot more sense if you could a consistent name so that we know it is the author who is commenting.
“I may have screwed up this analysis by failing to realize that annual variations had been removed from the records”
Sorry, there’s no ‘may have’ about it. This error needs to be flagged in an update at the top of the article.
I suggest you get there before someone like the “hotwhopper” site uses it to trash WUWT.
>> This error needs to be flagged in an update at the top of the article.
Agreed. And for the same reason, the associated Willis E articles should be flagged as well.
I only read as far as: “On this basis, one might expect to see a fairly substantial annual cyclic variation in global mean temperature. I failed to recall any in the many plots of global temperature anomalies that I have seen, but thought perhaps that single years wouldn’t stand out clearly in long, noisy records.”
Then I scanned the comments to see if anyone had caught the error. A couple people did say that the annual variation is removed, but didn’t say how.
The annual variation does show up in the monthly average globaltemperatures, because the calculation intentionally takes it out. All of the 5 global temperature organizations use a 30 year period as the baseline. The January anomaly is calculated as the departure from the average of the 30 Januarys, not the departure from the average of all 360 months. Likewise for February and all the rest of the months.
This is done to purposely remove the annual cyclic variation.
Ok should be …does not show up in the monthly.
I wonder if the current orbit of the planet placed us nearest the Sun in northern summer instead of in January, would we see a scorching hot northern hemisphere in summertime.
More importantly, we would see a blistering cold northern hemisphere in the wintertime and have a glaciation…
Agreement at last 😉
If you really want find out the role clouds play, then you must consider the dust in our atmosphere. At least someone is looking in to it.
http://www.engineering.cornell.edu/magazine/features/dust.cfm
Dust’s role in climate change is “really complicated,” Mahowald says. In fact, one of its most significant effects on the climate is actually a cooling one. Dust affects the ”radiative budget,” or the ratio of incoming solar radiation to the radiation that is reflected from the earth. CO2, for example, traps only outgoing radiation—thus the term “greenhouse effect.” Dust, however, can alter the heat that both enters and leaves the planet’s atmosphere. “Dust acts like a greenhouse gas,” says Mahowald, “but it reflects solar energy too. We think that in the net, it actually cools.”
This essay is very confused. One of the bigger sources of confusion is that the author does not understand that it is not just the magnitude of the forcing that matters but also the timescale over which it varies. The Earth…especially the oceans…have a large heat capacity that means there are large relaxation time scales. The more rapidly a forcing varies, the more heavily the response will be damped because of this. (It’s not difficult to write down some basic differential equations to illustrate this.)
After all, the radiative forcing in most places on the Earth varies by many hundreds of W/m^2 over a time of 12 hours (between day and night) but we don’t see the temperature varying nearly as dramatically as we might expect from that! [In this case, the variation is local, not global, but the winds and ocean currents are not fast enough to equilibrate between day and night, so that is not the fundamental reason why the temperature doesn’t vary as dramatically as we would expect from this change in forcing.]
“The feedback that negates the effect of 22 W/m2 should be of huge concern to climate modelers.”
Why? If you had demonstrated that the models show a big variation due to this 22 W/m^2 forcing then, yes, that would be a problem if it is not seen in the empirical data. However, while you have analyzed the empirical data, you have presented exactly zero evidence that the models are getting this wrong.
And, as I have explained above, the argument that the models predict a significant temperature change for a variation of 4 W/m^2 over long time scales means that they will necessarily predict a big variation due to this 22 W/m^2 forcing over a much shorter time scale is simply not correct.
In fact, I would turn things back on the author and say that the fact that Ice Ages occurred from what are estimated to be quite modest forcings should be of huge concern to the author.
I think that if you will go back and read what I wrote, you will see that I calculated a 0.45 C temperature swing for an annual 22 W/m^2 cycle and also found that the effect would be 5X larger if the cycle period were 10 years. The serious error that I made consisted of failing to recognize that anomaly records suppress annual variations.
Stan, a larger error is that you are confusing power for energy. You say “calculated a 0.45 C temperature”, but where did do any thermodynamic calculations? As a PhD physicist, you must be familiar with thermodynamics. Once upon a time, a PhD thermo professor had a graduate student who couldn’t do his master’s thesis. The professor asked me, a BSEE student, to help him. I ended up doing all the analytical work, writing 25 differential equations in 25 unknowns. I then wrote software to numerically compute the time domain results. In short, I could have earned a masters in thermo. There is no short cut to doing this work, like waving your hands and assume a fictional radiative balance still eons away.
joeldshore says:
it is not just the magnitude of the forcing that matters but also the timescale over which it varies. The Earth…especially the oceans…have a large heat capacity that means there are large relaxation time scales.
Except TSI forcing isn’t the same as GHG forcing. TSI is partially stored in the oceans. GHG infrared hardly at all since it doesn’t significantly penetrate below the surface. Increase GHG IR and it manifests immediately on both land and ocean. Negligible relaxation time (weeks at most).
If you want to argue that GHG IR somehow increases TSI at the surface (thru albedo/clouds?), you’re welcome to demonstrate it.
These arguments are beyond silly…Even skeptics like Willis Eschenbach don’t buy them. The reason GHG infrared don’t penetrate that far is because it is because water so strongly absorbs it. So, you are basically arguing for a magic mechanism by which waters strong absorption of GHG IR negates its effect. It just demonstrates how some people’s scientific views are driven mainly by wishful thinking.
Wishful thinking is believing that man-made global warming is happening in a measurable way, without any testable, empirical evidence. That belief is more religion than science.
No, joel, I don’t think it “negates” the effect — read what I wrote. You still don’t answer my question about time-relaxation of GHG IR effects compared to solar SW. You brought up time-relaxation effects in the first place.
And an insult — “Even skeptics like…..”
Back at ya — “Even rent-seeking academics like…..”
This sentence makes no sense whatsoever, as “anomalies” are substantial departures from “the rule” or, more accurately, the middle of a distribution. As such, they occur rather infrequently.
6. Anomaly in Meteorology. the amount of deviation of a meteorological quantity from the accepted normal value of that quantity.
perhaps the 22 w per m2 is what drives the el nino event which also peaks in january.
Annual cycles are certainly present from the 22 watts per square metre variation.
Earlier comments have given the 4 to 5 degree C annual temperature change.
Many of the multitudinous plots from Bob Tisdale have shown the quasi-annual variation of half a degree or more on the NINO 3.4 region. As well a look at the Outgoing Longwave Radiation (OLR) plots shows quasi annual variation with roughly 17 watts per square metre more going out on 1st October compared to 1st January.
However there are not annual El Nino events. They only occur when the climate system slips away (or is nudged?) for a quick circuit or two around a different strange attractor.
@lsvalgaard
“More importantly, we would see a blistering cold northern hemisphere in the wintertime and have a glaciation…”
According to the current consensus, the existing configuration of the Earth’s orbit (minimum TSI at 65N in July) favors the onset of glaciation because the summer in the NH has a hard time melting all snow at high latitude. How cold the winter is doesn’t really matter because it is always cold enough to produce snow and ice.
When the Earth’s orbit has the reverse configuration, we would have maximum TSI in July. If the annual water vapor cycle is really governed by NH land mass, the water vapor peak would still be around Sep (same as today). Together these conditions would make NH summers exceptionally hot and (I agree) winters exceptionally cold. My point is, are the summer/winter temperature differences greatly attenuated by the current Earth orbit configuration, and in 10.000 years (?) time we’ll see Antarctic winters and Saharan summers in the current temperate zones? My guess is that the water vapor cycle is actually governed by the wet oceans, not by the dry land, and in 10.000 years time the water vapor cycle will have reversed to balance the reversed swings in TSI.
Anthony, this article really needs an update up top and bold, pointing out the flagrant error which makes most of what he says and his conclusions totally invalid.
Finding that there is virually no annual signal in an anomaly dataset is hardly surprising, there’s not supposed to be any ! At that point the logic of the rest of the article falls apart.
I realise that you don’t have time to check everything in detail and you probably took this aritcle of trust because of the credentials of the author.
However, to leave this uncorrelcted is very poor and just gives ammo to your detractors who will relish such a silly and careless article as an example of what “climate deenyers” like to put forward as science.
As it stands it reads well and is very misleading to anyone who does not plough through the 200 or so comments and find one of several people pointing out the error.
This site is a mine of good information and articles but it does not take many like this to seriously damage credibiltiy.
Best regards, Greg.
MODs, what happened to the convention of posts using out host’s name being held back for his personal attention? That last one came straight up.
Another I posted just after just disappeared without trace.
Greg, I am sorry that I could not get a correction done immediately, but I have submitted one along with an apology for the error. I assume that it will eventually be posted, but if not look me up at swosu.edu and request a copy. Stan
“Kasper you have it 100% correct. When aphelion occurs during the N.H. summer is when glaciation chances are much greater. .
Kasper Almholt
November 13, 2014 at 12:06 am
@lsvalgaard
“More importantly, we would see a blistering cold northern hemisphere in the wintertime and have a glaciation…”
According to the current consensus, the existing configuration of the Earth’s orbit (minimum TSI at 65N in July) favors the onset of glaciation because the summer in the NH has a hard time melting all snow at high latitude. How cold the winter is doesn’t really matter because it is always cold enough to produce snow and ice.
When the Earth’s orbit has the reverse configuration, we would have maximum TSI in July. If the annual water vapor cycle is really governed by NH land mass, the water vapor peak would still be around Sep (same as today). Together these conditions would make NH summers exceptionally hot and (I agree) winters exceptionally cold. My point is, are the summer/winter temperature differences greatly attenuated by the current Earth orbit configuration, and in 10.000 years (?) time we’ll see Antarctic winters and Saharan summers in the current temperate zones? My guess is that the water vapor cycle is actually governed by the wet oceans, not by the dry land, and in 10.000 years time the water vapor cycle will have reversed to balance the reversed
When the Earth’s orbit has the reverse configuration, we would have maximum TSI in July. If the annual water vapor cycle is really governed by NH land mass, the water vapor peak would still be around Sep (same as today). Together these conditions would make NH summers exceptionally hot and (I agree) winters exceptionally cold. My point is, are the summer/winter temperature differences greatly attenuated by the current Earth orbit configuration, and in 10.000 years (?) time we’ll see Antarctic winters and Saharan summers in the current temperate zones? My guess is that the water vapor cycle is actually governed by the wet oceans, not by the dry land, and in 10.000 years time the water vapor cycle will have reversed to balance the reversed swings in TSI.
At the peaks of Willis’s seasonal +22 W/m^2 “TSI”, the earth is closest to the sun, but it is northern hemisphere winter time.
That means that the southern oceans are tilted towards that +22 W/m^2 insolation.
BUT !! That increased solar energy input is being driven deep into the southern oceans, with little energy impact on surface waters. So that excess heat is hiding out in the deep oceans, and isn’t going to show up anywhere in a matter of months, so it is NOT going to drive the MEAN global temperature to a higher than average Temperature.
Six months later (or earlier) it is the northern hemisphere land areas that face the -22 W/m^2 , but that solar energy does not propagate immediately into the interior of the land, but is manifested in high land Temperatures, and higher re-radiation, often at nearly twice the rate at the global average Temperature.
The land areas in the northern hemisphere can follow the TSI variations, at surface level, and thereby show seasonal differences, but the fact that southern hemisphere insolation, is largely deposited deep in the ocean so that it has little effect at the surface in times less than years, means that the bulk of the energy storage is happening in the southern hemisphere oceans, where the thermal lags are much to long to show up as an annual variation of mean Temperature.
Second, if 22 W/m2 variations peak to trough don’t produce noticeable temperature variations, why should the 0.25 W/m2 variations of TSI associated with solar cycles produce any measurable temperature variations?
Should the 22 W/m2 really produce differences? The difference in days between the equinoxes is about 11 days. So while the northern part of the Earth receives less energy per second in July, it is going slowest at that point so the northern part of the Earth has more time to build up the energy.
Global sea surface temperature does indeed vary about .45 degree C peak-to-trough. Have a look at the two graphs in http://bobtisdale.blogspot.com/2009_09_01_archive.html that are plotted in terms of temperature rather than temperature anomaly. I have noticed that such plots are not easy to find. Quick links to each of the two graphs are:
http://i32.tinypic.com/2jaiydh.png and http://i29.tinypic.com/2zgi8n7.png.
Also, water vapor content in the atmosphere is not a good indicator of clouds. If relative humidity stays the same, then a major change of temperature can cause a massive change of water vapor content with no change in cloud cover. In fact, my experience looking at cumulus clouds is that for a given surface relative humidity, their coverage varies slightly inversely with temperature.
Donald L. Klipstein commented
Rel humidity is just the % of water vapor the air hold at some temp. For rel humidity to stay the same with a large change in temps means the absolute amount of humidity changed. Changing temp does not change how much water vapor is there, it does change dew point, which probably changes how likely clouds are. Though there are lots of Sunny humid places.
Donald,
You may already know all of that, but was just describing the effect of a large change in absolute humidity with a temp change as an example, if so, sorry to jump in.