Estimating Cloud Feedback From Observations

FYI
Longwave infrared (LWIR) begins at 5 micrometers. For all practical purposes sunlight contains no LWIR energy. What little it does have never makes it to the surface as greenhouse gases block it. Also for all practical purposes the earth emits nothing but longwave infrared. There is a wide stark divide in the frequency domains of sunlight and thermal emission from the earth.
Moreover, different materials, not just just greenhouse gases but surface materials such as ice, water, rocks, soil, and vegetation have radicially different absorption and emission characteristics across all frequency ranges. It borders on ludicrous to lump all electromagnetic energy into “Watts” and all matter into “surface” or “atmosphere”. When you make simplifications that border on ludicrous you get answers that border on ludicrous. Garbage in, garbage out. All the fancy statistical math in the world won’t restore highly critical details of how EMR interacts with different forms of matter once they are left out.

Peter Miller says:

If cloud feedback was positive – as stated by the IPCC – it is difficult to see how exponential heating of the Earth’s surface would not occur. The argument is more CO2, therefore more heat, therefore more evaporation and therefore more clouds and therefore more heat and so on.

The piece you are missing is that infinite series sometimes converge to finite values. For example, the geometric series 1 + (1/2) + (1/4) + (1/8) + (1/16) + … converges to the value 2. Hence, if a positive feedback responded to a warming by CO2 of 1 C by producing an additional half C of warming, and then the feedback responded to that half C of warming by producing an additional quarter C of warming, and so on…then what you would end up with is not exponential heating but simply the multiplication of the original heating by a factor of 2.

@Myrrh
> How much would this change what happens to the clouds?
> http://journals.ametsoc.org/doi/abs/10.1175/2010JAS3282.1
It doesn’t change anything. Total solar insolation is 1200 Watts at top of atmosphere. Energy in longwave infrared range (>5um) is 1% of that or 12 Watts. Virtually none of that 12 Watts makes it to the cloud deck as it is absorbed by O3, CO2, CH4, H2O, sulfate aerosols, nitrogen compounds, and a host of other molecules between the cloud deck and TOA.

Just looking at the pretty colors 🙂 it would appear that some of the commenters are correct: you need to divide it up between landmass and ocean.
As a preliminary proxy for that, do latitude bands. 0 – 65 at 5 degree cells gives 13 cell bands. Do it 5/4/4, that is, 0-25, 25-45, and 45-65. I predict that the 0-25 band will look very much the same whether Northern or Southern hemisphere, but the others will be quite different because the land distribution is quite different. You really want to separate out land and ocean, but bands might be simpler as a first cut.
Regards,
Ric

PS, one way to test what I say about regression attenuation is to invert the axes and redo the ols fit. If the result is good one slope will be the inverse of the other. I think you will get a shock how different they are. Clearly the result should not depend on which way you plot the data … unless I’m right about OLS.
Willis says: “Report back with your results …”
My result IS just this, that doing OLS on this kind of data is fundamentally wrong and I’ve said why. I don’t need to reproduce your errors to prove it to you. Do it yourself. [hint reverse the arguments you pass to lm() ]
I did post a link to a graph where I have done this on similar data and and link to a thread where I covered this with TroyCA. He did listen and agreed.
If you want to dismiss the “positive feedback” results of Dessler, F&G et al this is the easiest and most incontrovertible route. Since the results of this flawed method are the only empirical justification for positive feedback in models and that is the only reason the models produce alarming warming this seems to me to be the crux of the whole AWG battle.

“”””” Steve from Rockwood says:
October 9, 2011 at 10:19 am (Edit)
Willis,
I made an error in my earlier post. Of the radiation reaching the earth, only about 1% is longwave (> 4 um). The other 99% is shortwave. Sorry to display my ignorance but that’s how I learn.
———————-
So virtually all incoming solar radiation is shortwave. That explains Dave’s comments. “””””
Well take heart Steve; ignorance is NOT a disease; we are all born with it. The Library of Congress is one of the world’s largest repositories of information about most of which, most of us are totally ignorant.
But I’m happy to see that you found some correction for your earlier statement that 53% of the solar spectrum was “longwave”.
It would be useful, if persons who are interested in this whole climate energy business acquainted themselves with certain rather basic pieces of information. The first I would suggest is the specific shape of the Planck Black Body radiation curve.
The version I would most strongly recommend is the universal normalized BB curve as published in the standard Optics Text; Modern Optical Engineering, by the late Warren J Smith, who worked for many years at Infra_Red Industries in Santa Barbara California.
He plots the Spectral Radiant Emittance (W.cm^-2.micron^-1) as a fraction of the peak value at the spectrum peak, as a function of the wavelength also scaled to the spectral peak wavelength.
So the relative wavelength goes from 0.15 to 50, and the vertical axis has two scales ; a linear one from 0.0 to 1.0, and a logarithmic one from 1.0 down to 10^-5. From this one can deduce the behavior of almost any thermal radiator, at least qualitatively and often quite quantitatively.
Some important general properties (of BB radiation) are.
1/ (almost) exactly 25% of the total energy is radiated at wavelengths shorter than the peak wavelength, and 75% at longer wavelengths.
2/ Only 1% of the total energy survives at wavelengths shorter than 0.50 times the peak wavelength.
3/ 50% of the total energy is emitted below about 1.5 times the peak wavelength (closer to 1.45).
4/ Only 1% of the total energy is emitted at wavelengths longer than 8 times the peak wavelength.
5/ The Spectral Radiant Emittance is down to 10^-5 at 0.20 times the peak wavelength and 40 times the peak wavelength.
The other most important relationship is the Wien Displacement Law, which says that the Temperature (Kelvins) times the peak wavelength, is a constant (2897.8 Kelvin.microns.
Apologies to the chemists and molecular spectroscopists who think in terms of Wave numbers (frequency) rather than wavelength. Despite the rationale for using frequency; given that
E = h.(nu) , I have yet to see my first plot of the solar spectrum plotted on a frequency scale.
Translated to the solar spectrum TSI, in its near BB guise at roughly 6,000 K. Other sources give 5900 K as the best fit BB curve fit, or 5770 as the value best meeting the TSI value which was 1353 Wm^-2, when that was published, so likely 5800 K at today’s 1366 Wm^-2.
So Wien’s law gives about 0.5 microns for the TSI spectral Peak, so 98% of the energy lies between 0.25 microns, and 4.0 microns. and the 50% division is at about 740 nm.
As for “visibility”, The commission on Colorimetry of the Optical Society of America cites Standard Luminosity values for the Photopic Luminosity curve of the eye from about 385 nm to 760 nm. at which points the value is 10^-4. This is not the extreme of the eye sensitive range. The dark adapted eye is capable of seeing single photons, at least in the blue-green range, so 10^-4 is not invisible. Warren Smith gives eye sensitivity values in the near infra-red out to 1.1 microns wavelength, where the sensitivity is 10^-11..
I tend to place the solar energy “short wave” radiation as being the 200 nm to about 2.0 microns range even though about 7% of solar energy survives past that. But the “long wave” part of the infra-red spectrum has some effect from about 2.0 and certainly by 4.0 microns.
A final key plot to have is the air mass one ground level solar spectrum. This plot corresponds roughly to the clear air surface maximum irradiance; before any albedo effects are considered.
Well not all, because the first major return of solar spectrum energy to space, in elastic scattering processes, is the Raleigh scattering of the short wavelengths which result in the blue sky. The blue sky looks the same looking down on the blue planet, as it does looking up, so the blue sky you see looking ap remote from the solar disk, represents exactly the amount of solar energy in the shorter wavelengths that is immediately lost to space, and is a large part of the loss from the 1366 Wm^-2.
The big mystery to me, is this almost childish fascination with the major climate calamity that is purportedly created from a source that is modelld quite closely by the LWIR emission from an ordinary bottle of drinking water at about room Temperature. It emits a near BB spectrum at about 400 Wm^-2 with a spectral peak of about 10.1 microns; corresponding to the average surface Temperature of the planet, as immortalized By Dr Trenberth’s amazing cartoon drawing.
Meanwhile, there is virtually total neglect of the effect of water both as a vapor or as clouds, on the real energy source driving our climate; the energy supplied by the sun.
FEEDBACK networks normally operate, by sensing the system OUTPUT, and modifying the system INPUT. One does not normally connect a feedback network to some largely irrelevant noisy output, which is what the surface LWIR actually is.
On any average mid-summer day in the north, the earth can enjoy a total surface Temperature range from as low as -90 C at places around Vostock in Antarctica, up to about +60 deg C in North African and middle eastern deserts. The surface LWIR emittance covers at least an 11 to 1 range, from nearly double the sacred average of 390 W/m^2, to about 1/6th of that value.
And that entire range can exist simultaneously; so we worry about whether or if, the average may have changed by 0.6 deg C in the last 150 years, and that from a quite corrupted and improper global sampling methodology.
When you connect the major climate feedback (water) to the INPUT (the sun) you find, that the feedback can never ever be positive. (more) Water can only lower the solar energy that reaches the earth surface; it can never increase it. CO2 also acts to reduce incoming solar energy, but not to the extent that water does.

Troy’s post I linked, looking at water vapour vs CERES radiation budget had an r2 of 0.03
He initially posted a “slope” of -0.19 , when he did it the other way around he got -6.4
We’re not talking +/-10% here.
Least squares does not work unless your x variable is a CONTROLLED variable.
In Willis’ case here I expect it will give a much more negative slope the other way around. So it may establish the sign of whatever it is measuring.
In the Dessler / F&G analysis the fundamental question is which side of 3.3 is it. This means the attenuation can change the “net feedback” from negative to positive.

I may be completely misunderstanding what you’re doing here, but if you are subtracting the temp of the month ahead from the current month I can see why Nick Stokes implies there could be a seasonal bias – and one which would presumably apply in one direction for one half of the year in each hemisphere (days lengthening or shortening) and then in the reverse direction for the rest of the year (for that hemisphere). The hemispheres would be out of phase and you’d probably expect a 4 quadrant plot which is what you show. If you treated the hemispheres separately AND split the year into 2 parts for each hemisphere you could run the subtraction both forward and backward for each of the 4 hemisphere/season combinations. IF each forward/backward run showed the same trends you could then rule out the seasonal signal (which may be much of your ‘noise’). If there’s still a negative trend in temp with increasing cloud, you’ve got a very interesting result.