Total solar irradiance, also called “TSI”, is the total amount of energy coming from the sun at all frequencies. It is measured in watts per square metre (W/m2). Lots of folks claim that the small ~ 11-year variations in TSI are amplified by some unspecified mechanism, and thus these small changes in TSI make an observable difference in some aspect of the temperature.
In that regard, here are the monthly variations in TSI (as a global 24/7 average) as shown by the CERES data:
Figure 1. Variations in TSI. The upper panel (red) shows the actual measured TSI. The middle panel shows the seasonal component of that variation. The bottom panel shows the ~ eleven-year variation in TSI once the seasonal data has been removed.
There are oddities in this record. Overall, the ~ eleven-year variation is a bit more than a quarter of a W/m2. However, from late 2000 to early 2001, the TSI dropped a bit more than a quarter of a W/m2. However, I digress …
My question is, 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?
To get an idea of the predicted effect of this variation in TSI, using IPCC figures this TSI change of 22 W/m2 is about the same change in forcing that we would get from six doublings of CO2 … that is to say, CO2 going from the current level (400 ppmv) to the extraordinary level of 25,600 ppmv.
In addition, again according to the IPCC, using their central value of 3°C warming per doubling of CO2 (3.7 W/m2 additional forcing), this change in forcing should be accompanied by a change in temperature of no less than 18°C (32°F).
Now, I can accept that this would be somewhat reduced because of the thermal lag of the climate system. But the transient (immediate) climate response to increased forcing is said to be on the order of 2°C per doubling of CO2. So this still should result in a warming of 12°C (22°F) … and we see nothing of the sort.
I say this lack of an effect of the TSI changes is because the climate system responds to the current conditions. The climate system is not some inanimate object that is simply pushed around by external forcings. Instead, it reacts, it responds, it evolves and varies based on the instantaneous local situations everywhere. In particular, when it is cold we get less tropical clouds, and that increases the energy entering the system. And similarly, when it is warm we get more tropical clouds, cutting out huge amounts of incoming energy by reflecting it back to space. In this way, the system reacts to maintain the same temperature despite the changes in forcing.
However, I’m happy to listen to alternate explanations and to consider opposing evidence … so if you think that the IPCC is right when it says that changes in temperature are driven by the changes in forcing, I ask you why the annual forcing change of 22 W/m2 doesn’t seem to show a corresponding 12°C change in global temperature.
Best to everyone,
w.
My Request—if you disagree with someone, please quote the exact words you disagree with. This allows us all to understand just what you think is incorrect.
TSI does not tell the whole story. UV and X-ray energy is deposited directly to the atmosphere, the shorter wavelength to the ionosphere, the longer wavelengths additionally to the stratosphere {ozone}. Most of the sun’s radiation is at visual wavelengths for which the atmosphere is mostly transparent). That part of the sun’s radiation that is not reflected by clouds reaches the surface of the Earth where some is reflected {albedo} and the rest heats the surface, resulting eventually heating the troposphere (conduction, convection and latent heat). Radiation of heat takes place all the time, in the infrared part of the spectrum, but it is not as efficient a transmitter of heat.as the modes previously mentioned.
Over the course of the solar sunspot cycle, the free electron densities in the ionosphere may vary by a factor of 1.5 or greater, Temperatures and densities (at given heights) go up resulting in increased drag on satellites.
How much coupling is there between the upper layers and the lower troposphere?
Well when I was in school, the best measured value of TSI was 1353 W/m^2, not 1366.5 as in your fictional reconstruction.
Science progresses. The current value is 1361 W/m^2 which is the energy per unit time [second] impinging normally on a unit area [square meter]
Exists at the poles (polar vortex). It is obvious.
“The climate system is not some inanimate object that is simply pushed around by external forcings.” This statement is certainly true and applies to CO2 ‘forcing’ as well as TSI. At present all we can do is measure temperatures on various parts of the Earth and record the results. There are no working models of any sort for either CO2 or TSI ‘forcing’..At present the record is unwavering and it looks like clouds are still doing their job. Thanks Water.
I presented a paper titled “Power Spectral Analysis of Total & Net Radiation” at a symposium on Earth’s Near Space Environment, 18-21 February 1975, held at the National Physical Laboratory, New Delhi and the same was published in Indian Journal of Radio & Space Physics, 6: 60-66 [1977]. In this study I observed the Total Solar radiation and net radiation intensities show sunspot cycle (10.5 years) and its multiples [21 & 42 years]. Solar flares follow the Sunspot cycle. At the same symposium I presented a paper titled “Effect of Solar Flares on Lower Tropospheric Temperature & Pressure”, which was published in Indian Journal of Radio & Space Physics, 6: 44-50 [1977]. I observed that the effect of solar flare is observed within 24 hr of the flare outburst only. —– but this variation shows a considerable relation to the general circulation pattern [high pressure or low pressure systems] over the region in different seasons. This paper was one of the 15 papers identified as research of unusual interest from the entire literature published around the world up to around 1975 by SCOSTEP [Scientific Committee on Solar Terrestrial Physics] under the Academy of Sciences of USA [abstract volumes were published in 1977].
Dr. S. Jeevananda Reddy
Willis
You State:
“where is the effect of the ~ 22 W/m2 annual variation in the amount of sun hitting the earth? That annual change is a thousand times the size of the eleven-year TSI change. Where is the effect of that 22 W/m2 change?
To get an idea of the predicted effect of this variation in TSI, using IPCC figures this TSI change of 22 W/m2 is about the same change in forcing that we would get from six doublings of CO2 … that is to say, CO2 going from the current level (400 ppmv) to the extraordinary level of 25,600 ppmv.”
////////////////////////////////////////////////////
Why not ask the other obvious question: namely given that we know that an annual variation of 22W/m2 which according to the IPCC, if they are correct, is the equivalent to some 6 doublings of CO2 leads to annual variation of just a few degrees C (ie., the difference between average GLOBAL temperatures when the Northern Hemisphere experiences its summer, and the average GLOBAL temperature when the Northern Hemishpere experiences its winter), what does this suggest about climate sensitivity to a change in forcing of just 3.7 W/m2 additional forcing?
Now I know that there are claims of CO2 residency times and lags etc which some would argue are such that one cannot make such a simple comparison.
But then again, it is those very same issues (which is predominantly the lag in heating up the oceans) that appear to make your question, regarding the effect in annual variation of TSI, equally invalid for considering the long term effects of changes in forcings running noy for months but for tens of years.
Richard, the equator has a fairly constant insolation and very little temp changes, but in the NH we get about a 22 degree C change in Average Temp in the UK, it is much higher further North, ie way over 40 degrees C in Russia etc.
What is the change in Insolation between Summer and Winter in the UK region.
The larger the disparity between the equator and the poles the quicker the energy will be moved out to space from the poles.
So the average TSI does not tell the whole story of our climate, has anyone mapped the insolation over the whole of the Earth’s surface?
Also concentrating on onlyTSI ignores the Solar Wind/Cosmic Rays and any Magnetic Coupling between the Sun and the Planets.
Richard: 22 W/m2 is only equivalent to 6 doublings of CO2 after equilibrium is reached. That is why they call it EQUILIBRIUM climate sensitivity. Below I calculated that it takes more that 36 years to for an 18 W/m2 forcing to warm the atmosphere and mixed layer. Long before then, Planck feedback and transport of heat below the mixed layer will slow the actual warming rate. From a practical perspective, the forcing is oscillating much faster than the planet’s thermal inertia (heat capacity) can respond, so it has negligible effect.
It also turns out that mean global temperature is highest (+1.5 degK above average) during summer in the NH – when solar radiation is lowest! See my full comments below.
CORRECTION
Further to my post at 12:49 am, the concluding part should have rad:
“equally invalid for considering the long term effects of changes in forcings running not for months but for a few years.”
Richard, you do understand that the sign for GAT in the SH summer when the earth is closest to the Sun is negative. The GAT response to plus 90 watt per M sq is cooling.
Vic Titious wrote:
October 25, 2014 at 10:29 pm
Given that the NH winter is at aphelion, …
=================================================================
Wrong.
NH winter is at perihelion, along with SH summer. (Jan 4th 2014)
NH summer, along with SH winter is at aphelion. (July 3rd 2014)
It should be obvious that all this is largely caused by thermal inertia and nothing else. Just consider the diurnal cycle: depending on the latitude of your location, there is a dramatic “forcing” of up to 1360 W/m^2 (at the equator) from dawn till noon, but the temperature response is also just 10°C or so. Likewise, the diurnal response is much less on or near the sea compared with dry places in the center of continents (e.g., the Sahara desert). Obviously, it’s the heat capacity of water causing the differences. Climate models easily capture these cycles, because the physics are quite simple. However, if one considers models as evil (as this blog usually does), one is left with useless speculations.
verbascose October 26, 2014 at 1:54 am
Since this is an annual variation, why would the changes over one day be relevant?
In any case, in many locations the daily temperature swings are 20°C, and the summer to winter swings are even larger … why doesn’t “thermal inertia” stop those swings?
w.
Verbascose if right. Thermal inertia (heat capacity) does not stop temperature changes, it damps them. And time scale matters, if the sun disappears for a few hours, the temperature change is much smaller than if it disappears for a few months.
Thermal inertia is much greater over water than land since convection can transfer heat deep into a body of water.
The heat capacity of the mixed layer of the ocean is something like 13 W-yr/m^2/K. So the seasonal change of 3.8 W/m^2 (see note) produces only a modest annual swing in mean global temperature. But a sustained change of 3.7 W/m^2 will produce, over time, a much larger change in temperature.
Note: I have corrected Eschebach’s error in units and accounted for the Earth’s albedo. I consistently use m^2 of the Earth’s surface, the value of 22 W/m^2 is for m^2 normal to the solar flux. There is a factor of 4 difference (the difference between the area of a circle and the area of a sphere with the same radius. And about 30% of solar radiation is reflected.
Oops. I owe Eschenbach an apology; he did include the factor of four. So corrected for albedo, the seasonal change is 15 W/m2.
Mike M.
Well, you compare a forcing over a century or so with the insolation changes over just one year, and I just do the same with your annual insolation changes: I compare it with a forcing over a much shorter time span. And it turns out that the time *does* matter a lot: thermal inertia *do* dampen the swings. That’s why the diurnal swings are somewhere in the same ballpark as those during the annual cycle, despite being caused by a dramatically higher forcing.
The prime cause is, as Mike M pointed out already, heat capacity. You have to take it into account and do the maths before making any claim.
It would be interesting to see, if available, a histogram of various wavelengths over time. Then one could see if there was any correlation with the various wavelengths and temperature over time. To limit ones view to TSI is narrow minded.
22 W/m2 is approximately one hundred times a quarter of a W/m2, not a thousand times
/ Jan
[Thanks, Jan. Fixed. -w]
Quite so.
Did the rest of the calcs assume 22W (correctly) or 1000x (incorrectly)?
22W/m2 (correctly)
w.
Looking at estimated global mean temperatures by month for the 20thC, the NCDC finds on average a 3.8C temperature difference between January and July. A jolt of this magnitude can be expected every year, year after year, and yet we have seen no tipping points, no mass extinctions, no etc etc. This is a genuine change in external forcing at the TOA. Work back to get an estimate of climate sensitivity on the scale of months.
Source: NVDC reports. e.g. for the last complete yer, 2013:
January 2013: ‘The average combined global land and ocean surface temperature for January 2013 tied with 1995 as the ninth warmest January since records began in 1880, at 0.54°C (0.97°F) above the 20th century average of 12.0°C (53.6°F).’ http://www.ncdc.noaa.gov/sotc/global/2013/1
July 2013: ‘The combined average temperature over global land and ocean surfaces for July 2013 was the sixth highest on record, at 0.61°C (1.10°F) above the 20th century average of 15.8°C (60.4°F).’
http://www.ncdc.noaa.gov/sotc/global/2013/7
Although we are closer to the sun in January than in July, the extensive land area of the northern hemisphere makes the northern summer have the warmest global mean temps.
When talking about the size of the transient climate response one has to relate it to a timeframe. The shorter timeframe you use, the lower transient climate response you will get. The annual changes in TSI is a much shorter timeframe than the IPCC use when the transient climate response is calculated.
When estimating the transient climate response to 2°C the scenario used by IPCC is the immediate measured response when CO2 increases with 1% annually. That means that it takes approximately 70 years to double the level. This means that most of the effect of a doubling has been going on for decades when the transient response is measured.
The 2°C is therefore not an immediate response to an immediate change in forcing, it is and immediate response to a gradual change in forcing. If you want to measure the effect of annual TSI variations on climate you need to know the transient climate response to a change in forcing in less than a year, and that is much smaller.
I have never seen a transient climate response on a sub annual timeframe estimated anywhere, but it would indeed be interesting to see it.
/Jan
seems spot on to me
True, but the GAT atmospheric observed response to this immense change in TSI, which is about 90 W/m2 at the TOA, is to cool. I think a better formation of Willis question is to ask does the earth gain or lose energy during perihelion? Clearly the atmosphere loses energy, but how much is entering the oceans?
If the annual variation is that large in W/m2, we can surely get a value for the response delay, and then look for the same, more attenuated, signal of longer term changes in irradiance?
Your analysis leaves out the bicentennial component of the TSI. when both the 11 year cycle and the bicentennial component are both taken into account then it is clear that the decline of the TSI will lead to a new ice age. The decline is not compensated by a decrease in the thermal energy emitted into space from the earth. See work of Dr H Abdussamatov of Polkovo Observatory St Petersburg http://www.ccsenet.org Applied Physics Research Vol 4 No1 feb 2012 This is on my blog 12 March 2013 http://scientificqa.blogspot.co.uk
Ice-ages occur from regional (Milankovitch) solar changes, not overall TSI changes.
Terri Jackson says “Your analysis leaves out the bicentennial component of the TSI. when both the 11 year cycle and the bicentennial component are both taken into account then it is clear that the decline of the TSI will lead to a new ice age. ”
In addition to a cycle of 208 years which has recently turned downwards, there is a 2300 year cycle which is still on the increase for a long time to come. No ice age yet.
I just assumed this this was either so small as to have no effect or it was hidden by their adjustments to the temperature data.
If as you say it is the equivalent of going from 400 ppmv to the extraordinary level of 25,600 ppmv, it appears to be unequivocal proof of what I have been saying which is that the feedback effects are overwhelmingly negative for increases in CO2.
The best estimate of the direct effect of CO2 is 0.6 for a doubling of CO2 by Hermann Harde (uniquely using the latest spectral data for HITRAN).
I was suggesting modest feedbacks so a likely actual warming of 0.4C/ doubling. I think your figures suggest an even higher level of feedbacks so I’d now suggest 0.2-0.3 / doubling.
In other words, an order of magnitude less than the IPCC “unequivocal” predictions.
“I say this lack of an effect of the TSI changes is because the climate system responds to the current conditions. The climate system is not some inanimate object that is simply pushed around by external forcings. Instead, it reacts, it responds, it evolves and varies based on the instantaneous local situations everywhere. In particular, when it is cold we get less tropical clouds, and that increases the energy entering the system.” I think the Wiilis’ arguments are correct. The global temperature has its maximum in Jul and its minimum in Jan. The earth is nearest to the sun in Dec. This seasonal effect is mainly caused by the unequal distribution of land and oceans on both hemispheres. The TSI changes are a small correction to the difference between the extremes of the global temperatures.
Thanks, Willis.
Well, I can’t give a good mathematical answer to that either but I can offer some interesting facts to speculate on.
Surprisingly, global mean temperatures are higher when the Earth is farthest from the Sun! This occurs in July and coincides with the Northern Hemisphere(NH) summer. Because land masses warm more readily than oceans (and the NH has more land mass) the world is actually warmer, even though it is receiving 22 W/m2 less energy from the Sun.
Furthermore, because most land is in the NH, CO2 levels decrease in the NH spring (photosynthesis) and are at their highest in the NH winter.
The NCDC estimates a mean global temperature difference, averaged over the 20thC, of 3.8C between January and July.
… I ask you why the annual forcing change of 22 W/m2 doesn’t seem to show a corresponding 12°C change in global temperature. …
System lag is greater than 6 months?
But is it? If we look at individual locations we note they are warmer in the summer (and cooler in the winter) with a lag of about 6 weeks or so between maximum (minimum) insolation.
Is it worth looking at the annual temperature cycle of locations “close to the equator” to see if they reflect, not only the seasonal cycle, but also the annual variation in solar energy.
The North Atlantic sea surface temperature does vary by an effective radiating value of 26 W/m2 over the seasonal cycle (+/-.13 W/m2).
Its just radiating at an effective value of 411 W/m2 in early April and 437 W/m2 in early September versus the solar insolation average of 240 W/m2 in the area (by chance, the north Atlantic on average receives exactly the global solar insolation value).
The average climatology in degrees C of the North Atlantic defined by the AMO region by month.
http://www.esrl.noaa.gov/psd/data/correlation/amon.climo.data
So, it is 170 W/m2 higher than the solar insolation value due to the greenhouse effect and it is affected by the northern hemisphere solar insolation seasonal cycle (versus the global insolation cycle) and it is lagged about 80 days behind the peak solar insolation cycle on June 21.
Thus, there is the greenhouse effect to take into account and the long lags (slow drawdowns and slow accumulations of joules over time that matter exhibits) and then different distribution of that matter in the hemispheres (oceans versus land versus ice which all have different joule absorption/drawdown rates) .
No answer but a description of where the answer lays.
The model used by Dan Pangburn is very easy to understand and gives convincing results. He uses the method used by control engineers, which I understand well as I have been dealing with control engineering for decades and been a lecturer in the University of Iceland where I thought control theory for several years. (Text book Ogata). I also have a fair understanding of thermodynamics having worked in the geothermal field for decades.
It is wrong to compare the TSI and atmospheric/sea temperture directely. That does not work. The better method is to compare the time integral of TSI with the temperature trend, but the best and correct method is to use a model similar to the one used by Dan which uses the time integral of TSI as well as the radiation dissipation to space.
Dan Pangburn, who has a MSc degree in mechanical engineering, used his good knowledge of thermodynamics and control theory to make his model that is described here at Hockey Schtick http://hockeyschtick.blogspot.com/2013/11/the-sun-explains-95-of-climate-change.html
His model is very convincing. The result is as expected.
Image:
http://1.bp.blogspot.com/-hZs bryXH5c/Uo_Qzo1q3OI/AAAAAAAAAKM/VS6yWWq1wj4/s400/Slide1.JPG
My comments seem to be trapped in a queue somewhere, so there is a chance this one will be a repeat of an earlier one yet to be liberated. Or, it might just join it in limbo.
There is about a 4C shift in global mean surface temperature every year as we orbit the sun. This is a response to a genuine change in external forcing at the top of the atmosphere.
Here are some results for the last complete year, 2013, in January and July from the NCDC:
January 2013: ‘The average combined global land and ocean surface temperature for January 2013 tied with 1995 as the ninth warmest January since records began in 1880, at 0.54°C (0.97°F) above the 20th century average of 12.0°C (53.6°F).’ http://www.ncdc.noaa.gov/sotc/global/2013/1
July 2013: ‘The combined average temperature over global land and ocean surfaces for July 2013 was the sixth highest on record, at 0.61°C (1.10°F) above the 20th century average of 15.8°C (60.4°F).’
http://www.ncdc.noaa.gov/sotc/global/2013/7
Except the direction is wrong. So its not the sun’s forcing. We are closer to the sun in January than July!
What a difference the land makes!
“What a difference the land makes!”
and or, what a difference the oceans make. plus 90 watts per m-sq entering the oceans. TSI which strikes the land is instantly re-emitted to the atmosphere. TSI which penetrates below the ocean surface is lost to the atmosphere , some of it for just a bit, some of it for decades, some for longer. So the real question to be answered is does the earth gain or lose energy at this time.
How come no one ever steps back and looks at the big picture? There is a hot layer just below the surface of the Ocean (heated by the Sun of course). Heat flux from this area is primarily by conduction (360˚) This area and the corresponding ocean has a huge thermal mass…. This thermal mass quite effectively dampens and often eliminates temperature changes from daily 8000w changes in solar radiation.
To think that a few watts of radiation that penetrate deeper into the ocean than average can make a measurable change to the surface temperature is, how shall I put it? Odd?
Paul Westhaver on 25th Oct at 9:33 says:
…Lots of folks claim that the small ~ 11-year variations in TSI are amplified by some unspecified mechanism, and thus these small changes in TSI make an observable difference in some aspect of the temperature….
Actually…
…Lots of folks claim that the small ~ 11-year variations in TSI [influence] some [unknown] mechanism, and these small changes in TSI [contribute] to an observable difference in temperature….
Paul, thanks for clearing that up. I’ll go further…
There’s much confusion that results from the use of the word ‘amplified’. Although it might be a useful analogy in very general terms, it is really only moderation of the existing TSI input via attenuation that can have any hypothetical effect.
In other words, the hypothetical moderating mechanism is to do with the attenuation of TSI from some slightly higher value that it would have had in the absence of that mechanism. If the mechanism diminishes in its effectiveness for some reason, it will moderate/attenuate TSI to a lesser degree. This lesser attenuation will result in TSI increasing somewhat, though still under the influence of moderation- that is where the word ‘amplification’ is introduced erroneously. It clearly can’t be amplified using some additional outside energy source, that is, a power source in addition to the Sun.
This is why Mike Wryley (Oct 25th at 8:25 pm) asked a perfectly reasonable question regarding the fact that all amplifiers need an external power source so where did this amplifier’s source come from? But there is no amplifier, just a (hypothesised) attenuator. That attenuator just happens to mimic the behaviour of an amplifier when it begins to lose its moderating capacity and allows the TSI input to rise.
I think the word ‘amplified’ and any of its derivatives should not be used when discussing this purported moderating mechanism. I’ve seen it used in several discussions including David Evans’ solar notch filter. I’m not sure in which cases it is used carelessly and in which cases it is used with intent to obfuscate the issue and make the hypothetical moderating mechanism appear to defy the laws of thermodynamics. It certainly can sound that way in some carefully constructed contexts.
I admit that even my use of the word, ‘attenuated’ could cause confusion because it suggests ‘absorption’ of TSI when I really mean partial ‘blocking’ via any hypothetical means (including increased reflectance via enhanced albedo- the opposite of absorption!).
Any suggestions for a clear unambiguous term to describe the moderation/attenuation effect as opposed to the spurious ‘amplification’ effect? If we settle on an unambiguous term for it we can move the discussion on from semantics that confuse us to the actual discussion of whether the mechanism exists or not.