Congratulations (finally) to Spencer and Braswell on getting their new paper published

WUWT provided a primer on cloud feedbacks on June 12th, 2009, followed by Willis Eschenbach’s “thermostat hypothesis” also recently published. This new paper by Spencer and Braswell is in the same theme as these.

As clouds rise above the ITCZ, cloud tops create a reflective albedo, automatically limiting incoming solar radiation

On the diagnosis of radiative feedback in the presence of unknown radiative forcing

Roy W. Spencer and William D. Braswell

Received 12 October 2009; revised 29 March 2010; accepted 12 April 2010; published 24 August 2010.

Abstract: The impact of time‐varying radiative forcing on the diagnosis of radiative feedback from satellite observations of the Earth is explored. Phase space plots of variations in global average temperature versus radiative flux reveal linear striations and spiral patterns in both satellite measurements and in output from coupled climate models. A simple forcingfeedback model is used to demonstrate that the linear striations represent radiative feedback upon nonradiatively forced temperature variations, while the spiral patterns are the result of time‐varying radiative forcing generated internal to the climate system. Only in the idealized special case of instantaneous and then constant radiative forcing, a situation that probably never occurs either naturally or anthropogenically, can feedback be observed in the presence of unknown radiative forcing. This is true whether the unknown radiative forcing is generated internal or external to the climate system. In the general case, a mixture of both unknown radiative and nonradiative forcings can be expected, and the challenge for feedback diagnosis is to extract the signal of feedback upon nonradiatively forced temperature change in the presence of the noise generated by unknown time‐varying radiative forcing. These results underscore the need for more accurate methods of diagnosing feedback from satellite data and for quantitatively relating those feedbacks to long‐term climate sensitivity.

Citation: Spencer, R. W., and W. D. Braswell (2010), On the diagnosis of radiative feedback in the presence of unknown radiative forcing, J. Geophys. Res., 115, D16109, doi:10.1029/2009JD013371.

Our JGR Paper on Feedbacks is Published

by Roy W. Spencer, Ph. D.

After years of re-submissions and re-writes — always to accommodate a single hostile reviewer — our latest paper on feedbacks has finally been published by Journal of Geophysical Research (JGR).

Entitled “On the Diagnosis of Feedback in the Presence of Unknown Radiative Forcing“, this paper puts meat on the central claim of my most recent book: that climate researchers have mixed up cause and effect when observing cloud and temperature changes. As a result, the climate system has given the illusion of positive cloud feedback.

Positive cloud feedback amplifies global warming in all the climate models now used by the IPCC to forecast global warming. But if cloud feedback is sufficiently negative, then manmade global warming becomes a non-issue.

While the paper does not actually use the words “cause” or “effect”, this accurately describes the basic issue, and is how I talk about the issue in the book. I wrote the book because I found that non-specialists understood cause-versus-effect better than the climate experts did!

This paper supersedes our previous Journal of Climate paper, entitled “Potential Biases in Feedback Diagnosis from Observational Data: A Simple Model Demonstration“, which I now believe did not adequately demonstrate the existence of a problem in diagnosing feedbacks in the climate system.

The new article shows much more evidence to support the case: from satellite data, a simple climate model, and from the IPCC AR4 climate models themselves.

Back to the Basics

Interestingly, in order to convince the reviewers of what I was claiming, I had to go back to the very basics of forcing versus feedback to illustrate the mistakes researchers have perpetuated when trying to describe how one can supposedly measure feedbacks in observational data.

Researchers traditionally invoke the hypothetical case of an instantaneous doubling of the CO2 concentration of the atmosphere (2XCO2). That doubling then causes warming, and the warming then causes radiative feedback which acts to either reducing the warming (negative feedback) or amplify the warming (positive feedback). With this hypothetical, idealized 2XCO2 case you can compare the time histories of the resulting warming to the resulting changes in the Earth’s radiative budget, and you can indeed extract an accurate estimate of the feedback.

The trouble is that this hypothetical case has nothing to do with the real world, and can totally mislead us when trying to diagnose feedbacks in the real climate system. This is the first thing we demonstrate in the new paper. In the real world, there are always changes in cloud cover (albedo) occurring, which is a forcing. And that “internal radiative forcing” (our term) is what gives the illusion of positive feedback. In fact, feedback in response to internal radiative forcing cannot even be measured. It is drowned out by the forcing itself.

Feedback in the Real World

As we show in the new paper, the only clear signal of feedback we ever find in the global average satellite data is strongly negative, around 6 Watts per sq. meter per degree C. If this was the feedback operating on the long-term warming from increasing CO2, it would result in only 0.6 deg. C of warming from 2XCO2. (Since we have already experienced this level of warming, it raises the issue of whether some portion — maybe even a majority — of past warming is from natural, rather than anthropogenic, causes.)

Unfortunately, there is no way I have found to demonstrate that this strongly negative feedback is actually occurring on the long time scales involved in anthropogenic global warming. At this point, I think that belief in the high climate sensitivity (positive feedbacks) in the current crop of climate models is a matter of faith, not unbiased science. The models are infinitely adjustable, and modelers stop adjusting when they get model behavior that reinforces their pre-conceived notions.

They aren’t necessarily wrong — just not very thorough in terms of exploring alternative hypotheses. Or maybe they have explored those, and just don’t want to show the rest of the world the results.

Our next paper will do a direct apples-to-apples comparison between the satellite-based feedbacks and the IPCC model-diagnosed feedbacks from year-to-year climate variability. Preliminary indications are that the satellite results are outside the envelope of all the IPCC models.

========================================

Be sure to check out Dr. Roy Spencer’s book:

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August 29, 2010 9:59 pm

Tim Williams,
As you linked to, the comment on their paper was rebutted,
Reply to “Comment on ‘Falsification Of The Atmospheric CO2 Greenhouse Effects Within The Frame Of Physics’ by Joshua B. Halpern, Christopher M. Colose, Chris H0-Stuart, Joel D. Shore, Arthur P. Smith, Jorg Zimmermann”
(International Journal of Modern Physics B, Volume 24, Issue 10, pp. 1333-1359, April 2010)
– Gerhard Gerlich, Ralf D. Tscheuschner

It is shown that the notorious claim by Halpern et al. recently repeated in their comment that the method, logic, and conclusions of our “Falsification Of The CO2 Greenhouse Effects Within The Frame Of Physics” would be in error has no foundation. Since Halpern et al. communicate our arguments incorrectly, their comment is scientifically vacuous. In particular, it is not true that we are “trying to apply the Clausius statement of the Second Law of Thermodynamics to only one side of a heat transfer process rather than the entire process” and that we are “systematically ignoring most non-radiative heat flows applicable to Earth’s surface and atmosphere”. Rather, our falsification paper discusses the violation of fundamental physical and mathematical principles in 14 examples of common pseudo-derivations of fictitious greenhouse effects that are all based on simplistic pictures of radiative transfer and their obscure relation to thermodynamics, including but not limited to those descriptions (a) that define a “Perpetuum Mobile Of The 2nd Kind”, (b) that rely on incorrectly calculated averages of global temperatures, (c) that refer to incorrectly normalized spectra of electromagnetic radiation. Halpern et al. completely missed an exceptional chance to formulate a scientifically well-founded antithesis. They do not even define a greenhouse effect that they wish to defend. We take the opportunity to clarify some misunderstandings, which are communicated in the current discussion on the non-measurable, i.e., physically non-existing influence of the trace gas CO2 on the climates of the Earth.

maksimovich
August 29, 2010 10:41 pm

jorgekafkazar says:
August 29, 2010 at 3:09 pm
2) GCMs assume that albedo is constant but the one conclusive thing found by experimental measurements is that the earth’s albedo varies a lot and it changes quickly.
This doesn’t seem to ring true, nor could I find that statement in the reference. Surely GCM’s (at least some of them) would account for seasonal ice/snow cover affecting solar heat input. Please explain or qualify your statement or cite a better reference.

Ramanathan
It is remarkable that general circulation climate models (GCMs) are able to explain the observed temperature variations during the last century solely through variations in greenhouse gases, volcanoes and solar constant. This implies that the cloud contribution to the planetary albedo due to feedbacks with natural and forced climate changes has not changed during the last 100 years by more than ±0.3%; i.e, the cloud forcing has remained constant within ±1 Wm–2. If indeed, the global cloud properties and their influence on the albedo are this stable (as asserted by GCMs), scientists need to validate this prediction and develop a theory to account for the stability

Dave Springer
August 30, 2010 2:32 am

jorgekafkazar says:
August 29, 2010 at 3:09 pm

Dave Springer says:
August 29, 2010 at 11:13 am
2) GCMs assume that albedo is constant but the one conclusive thing found by experimental measurements is that the earth’s albedo varies a lot and it changes quickly.

This doesn’t seem to ring true, nor could I find that statement in the reference. Surely GCM’s (at least some of them) would account for seasonal ice/snow cover affecting solar heat input. Please explain or qualify your statement or cite a better reference.

Everything I said that you question except perhaps “rapid” is supported in the following two quotes from the paper.
Rapid, I suppose, is a relative term. Clouds and snow can form and disappear rapidly in my opinion and these are what drive changes in albedo.
36 Most climate studies assume the albedo to be nearly constant in time, but
37 recent monitoring of the albedo, from different techniques, show that this is
38 certainly not the case.
53 Apart from these discrepancies, all the observational estimates of the Earth
54 reflectance are broadly consistent in suggesting changes in the Earth’s short-
55 wave forcing, both at the surface and at the top of the atmosphere, that will
56 have a large impact on the planet’s radiation budget

mikael pihlström
August 30, 2010 2:58 am

jeef says:
August 29, 2010 at 1:36 pm
Nice one Doc.
To those few wondering how his paper can read tamely in the conclusion yet Dr. Spencer be more vociferous the blogosphere, might I suggest you read his comments about how long it took to get published, and why. Therein lies the answer.
————
That answer is a little bit weak. Any author tends to overestimate the
explanatory power of his article. One function of a peer-reviewer
is to bring the author down to earth: ‘your results/observations are
not sufficient to support that particular conclusion’.
So there is no way of knowing whether (a) this normal moderation or
(b) hostility to sceptics, was the reason for the lengthy review process
in this case.
What can be said is that. had S&B been able to unequivocally show
that positive feedbacks are not important they would have broken
through any review-barrier, hostile or not. They could not do so
and the question remains: what’s so revolutionary about this work?

Gail Combs
August 30, 2010 5:05 am

Congratulations Spencer and Braswell, you are in good company.
Censorship of unwanted scientific findings is typical and an old tradition even here in the “free” USA.
Here is another example of censorship most people are unaware of.
It seems that Professor Lewis B. Allyn was the subject of expulsion proceedings from the American Chemical Society for writing an article for Ladies” World titled Your Child and the Soda Fountain” in 1915. In the letter from the St Louis section of ACS recommending his expulsion, Professor Lewis B. Allyn was accused of writing “articles tending to throw much suspicion on the prepared foods and beverages sold in this country, to arouse unnecessary alarm among the uninformed public, and especially to influence the purchase …. statements that can only be explained on the assumption that he is ignorant or that they are deliberately false…” Allyn tangled with the Rockefellers and Cocoa-Cola among others. This is during the time of the Pure Food and Drug Act ruckus – Allyn was a key player. see pg 36 McClure’s Magazine
It is ironic that now nearly a hundred years latter unscientific alarmism is happily endorsed by the ACS and other professional societies and the scientific truth is again subject to censorship. Big money sure does talk doesn’t it?

Ed_B
August 30, 2010 5:41 am

mikael pihlström says: “what’s so revolutionary about this work?”
You must be joking, right? This is really important, as we have actual measurements to show that the global warming due to CO2 is moderated by negative feedbacks, not positive feedbacks as postulated by the CAGW scientists.
It is evident to me that the sum of immediate negative feedbacks is a long term moderation of warming. Thus the CO2 induced sensitivity is not significant, just as the ice records show. and as current flatlined temperatures show.
This is HUGE!!

Pascvaks
August 30, 2010 7:04 am

Science has never been perfect. Indeed, on many occassions it has been quite imperfect. It is through trial and error and hard headed tenacity that progress is made in this, and every other form of endeavour. Merely to state that something is TRUE, or THIS, or THAT, is never enough. Merely to prove that something is TRUE, or THIS, or THAT, is never enough. If you wish to get the recognition of your contemporaries, you must wait. If you wish to get the recognition of the World, you must wait and wait, and wait –usually it will only come after you are gone to your Great Reward in the Hereafter. If you want to get a Nobel Prize, lately it all depends on who you know and how much political power they have, not what you know or what you can prove or what others of equal or greater merit in your field or in related fields said you did. Life’s a beach!
PS: Three cheers for Spencer and Braswell. Hip Hip..

George E. Smith
August 30, 2010 9:54 am

Well the late Carl Sagan, went to his grave; having spent a good part of his life looking for intelligent life in the universe; and never discovered so much as a single binary digit of observational scientific evidence, for the existence of such life, or for that matter, ANY life, outside a shell of about +/- 20 km about mean sea level on planet earth. Some aren’t so sure there is any intelligent life even within that shell.
So who wants to be the “climate scientist” who is destined to go to his(er) grave having searched for a cloud that made the surface in its shadow zone warmer, when it passed between the sun and the surface ?
Remember that “weather is not climate” thing; and if the mean global cloud cover on planet earth, increases for periods of climatic significance (how about 30 years), the mean temperature of the earth WILL go down; NOT up.
Clouds are always a negative feedback effect.
But the playing field is wide open for any “climate scientist” who wants to do a Carl Sagan type exit some day.
And people actually have to write scientific papers for journals to show this ?

Tim Clark
August 30, 2010 10:09 am

Ivan says: August 29, 2010 at 1:52 pm
What I objected to was the inconsistency between the previous Spencer’s advertisement of this new work as a positive demonstration of the negative long-term climate feedback, and his actual results which simply show that we don’t have a clue. The long-term climate feedback could well have been extremely positive, even more positive than the most extreme IPCC projections assume, and still be be quite consistent with this new paper of Spencer and Braswell.

Please reread this passage, I think the ramifications are eluding you:
Interestingly, in order to convince the reviewers of what I was claiming, I had to go back to the very basics of forcing versus feedback to illustrate the mistakes researchers have perpetuated when trying to describe how one can supposedly measure feedbacks in observational data.
Researchers traditionally invoke the hypothetical case of an instantaneous doubling of the CO2 concentration of the atmosphere (2XCO2). That doubling then causes warming, and the warming then causes radiative feedback which acts to either reducing the warming (negative feedback) or amplify the warming (positive feedback). With this hypothetical, idealized 2XCO2 case you can compare the time histories of the resulting warming to the resulting changes in the Earth’s radiative budget, and you can indeed extract an accurate estimate of the feedback.
The trouble is that this hypothetical case has nothing to do with the real world, and can totally mislead us when trying to diagnose feedbacks in the real climate system. This is the first thing we demonstrate in the new paper. In the real world, there are always changes in cloud cover (albedo) occurring, which is a forcing. And that “internal radiative forcing” (our term) is what gives the illusion of positive feedback. In fact, feedback in response to internal radiative forcing cannot even be measured. It is drowned out by the forcing itself.

They convinced the reviewers of JGR (is that publication prestigious enough?) that cloud cover is a forcing. There cannot be measurements of positive or negative cloud cover feedback. Feedback is irrelevant, and the IPCC reliance on an assumed positive feedback to support global catastrophe is erroneous. What part don’t you understand?

George E. Smith
August 30, 2010 10:14 am

“”” Dave Springer says:
July 8, 2010 at 6:43 pm
More info on earth albedo measurements:
http://bbso.njit.edu/Research/EarthShine/literature/Palle_Goode_2008_ASP.pdf
This is worth reading. It’s essentially a blunt indictment of the global circulation models that are being used to frighten the sheeple into global energy use governance.
Several key statements in it are:
1) There is no reliable way to accurately measure the earth’s albedo. The few methods being used are often in “unsatisfactory disagreement”. “””
Dave; I don’t know who you are quoting in the above 1) citation but I certainly agree with their conclusion; BUT, if that is the extent of their cloud comment; then they don’t even understand the problem.
The earth albedo contribution due to cloud tops, is just one aspect of clouds. Some clouds actually precipitate H2O molecules in various physical manifestations; such as rain, snow, sleet, whatever; and clouds that do that also tend to absorb large amounts of solar radiation and block it from reaching the surface. This effect can be even greater than the albedo effect.
So talking about “difficulties” in monitoring cloud albedo, is to totally avoid the issue that we don’t have any network that is ground based so it can monitor the total cloud attenuation effect on incoming solar radiation.
That can only be done from the surface by optical measurements of the resultant ground level total (solar) spectral irradiance on the surface.
Even the surface stations that measure surface or near surface Temperatures to input into GISSTemp and the like throw away valuable cloud information by simply reporting a daily min/max average for the temperature, instead of an actual integrated time/Temperature “area” that in some way can give a clue to the total cloud effect.
It’s hard to take any interest in the reported data, (on tempertaure anomalies) when it is clear from the methodology that the purveyors don’t even understand the problem.

Yuba Yollabolly
August 30, 2010 10:47 am

“Clouds are always a negative feedback effect.”
Not at night.

Ivan
August 30, 2010 11:03 am

Tim Klark: “They convinced the reviewers of JGR (is that publication prestigious enough?) that cloud cover is a forcing. ”
They convinced the reviewers of their previous paper the same thing, two years ago. My question is what is new here?
“Feedback is irrelevant, and the IPCC reliance on an assumed positive feedback to support global catastrophe is erroneous.”
As far as I understood Spencer the feedbacks are the single most important issue in climate science!
Further, it well may be true that assuming the large positive feedback is erroneous, but that does not follow from the Spencer’s results. That’s the problem. He himself says that we don’t know and have no way of knowing the long-term climate feedback, which is the only important feedback in the context of climate change. So, as I said, the real climate sensitivity which critically depends upon the long term feedback could have been even larger than the wildest IPCC projections, and that still will be quite consistent with the Spencer falibilistic position.

Tim Clark
August 30, 2010 12:01 pm

Ivan says: August 30, 2010 at 11:03 am
They convinced the reviewers of their previous paper the same thing, two years ago. My question is what is new here?……………………..He himself says that we don’t know and have no way of knowing the long-term climate feedback, which is the only important feedback in the context of climate change.

READ
As we show in the new paper, the only clear signal of feedback we ever find in the global average satellite data is strongly negative, around 6 Watts per sq. meter per degree C. If this was the feedback operating on the long-term warming from increasing CO2, it would result in only 0.6 deg. C of warming from 2XCO2. (Since we have already experienced this level of warming, it raises the issue of whether some portion — maybe even a majority — of past warming is from natural, rather than anthropogenic, causes.)

Mikael Pihlström
August 30, 2010 12:21 pm

Tim Clark says:
August 30, 2010 at 12:01 pm
READ
As we show in the new paper, the only clear signal of feedback we ever find in the global average satellite data is strongly negative, around 6 Watts per sq. meter per degree C. If this was the feedback operating on the long-term warming from increasing CO2, it would result in only 0.6 deg. C of warming from 2XCO2. (Since we have already experienced this level of warming, it raises the issue of whether some portion — maybe even a majority — of past warming is from natural, rather than anthropogenic, causes.)
————-
You seem to be quoting the post text for the home audience (WUWT)
all the time. The article is much less confident:
60. Striations in 9 years of global average CERES radiative
fluxes from the Terra satellite have a slope around 6 W
m−2 K−1 in net (LW + SW) radiative flux variability. This is
similar to the feedbacks diagnosed by Lindzen and Choi
[2009] from interannual variability in recently recalibrated
Earth Radiation Budget Satellite data, as well as that diagnosed
for a composite of 15 strong tropical intraseasonal
oscillations analyzed by Spencer et al. [2007]. Although these
feedback parameter estimates are all similar in magnitude,
even if they do represent feedback operating on intraseasonal
to interannual time scales, it is not obvious how they relate to
long‐term climate sensitivity.”
In the following numbered paragraphs (61-63) S&B nearly bend
over in introducing caveats and admissions of uncertainty concerning
the whole enterprise. Not exactly a knock-out of AGW.

George E. Smith
August 30, 2010 4:47 pm

“”” Yuba Yollabolly says:
August 30, 2010 at 10:47 am
“Clouds are always a negative feedback effect.”
Not at night. “””
Who says so ? When have you ever observed the surface temperature to increase after sundown; because of clouds in the sky?
The clouds in the sky at night are a result of the heat and humidity of the day; not the cause of the heat and humidity that preceeds sunset.
When you can show a pre-sunrise temperature that is higher than the previous post sundown temperature and show that clouds in the sky caused it; then you might be able to claim a positive feedback.
But last night’s weather is not climate.
ANY increase in the percentage of total global cloud cover over any climate significant time scale, must result in a decrease of total ground level insolation; both from cloud albedo increase; and increased absorption of additional solar energy by precipitable clouds.
Read “How Much More Rain, Will Global Warming Bring ?” SCIENCE for July 7 2007 by Frank Wentz (RSS Santa Rosa) et al. From actual satellite measured data; not from Playstation computer imagination. And then add RAIN=CLOUDS !

Yuba Yollabolly
August 30, 2010 7:59 pm

Mr Smith- You are right. Clouds don’t heat. But they needn’t heat to be a feedback. All they need to do is to slow the rate of cooling. That is their tendency at night.
“Who says so?” – Any basic weather text book will tell you that.
Although you are also right “last night’s weather is not climate”, night happens about half the time and the aggregate effect is very important to climate. Furthermore night makes up half of “always”.
I have reviewed Wentz et al (2007)
What I find is a study that indicates that globally The hydrologic cycle appears to increase at a greater rate than climate models have predicted. I don’t see any part that refers to “precitable” clouds nor additional radiation absorbed by them.
I did notice these comments however:
“…both climate models and observations indicate that the total water vapor in the atmosphere increases by about 7% K^-1.
More than 99% of the total moisture in the atmosphere is in the form of water vapor….”
You are aware the water vapor is a very significant GHG are you not Mr Smith?
Since most clouds do not rain I would say it is quite a jump to say “RAIN=CLOUDS”.
The last paragraph of the paper concludes:
“…Will warming really bring a decrease in global winds? [needed to account for the apparent decrease in the apparent discrepancy in precipitation found] The observations reported here suggest otherwise, but clearly these questions are far from being settled. “
Your citation does not in any way contradict my statement that clouds do not have a negative feedback effect at night.
HTH – yolo

Don V
August 30, 2010 8:42 pm

I am a biochemical engineer. I have been a lurker on various climate science websites for the last 6 years and have been trying real hard to understand the nature of the problem that has made the study of climate so polarizing. Wand away from understand the difficulty in the physics of this massive problem, it is that there are so many independent variables

Don V
August 30, 2010 10:54 pm

Sorry I wasn’t clear. My first post here was sent in error. Please delete it. My second post expressed my thoughts clearly.
REPLY: I have no idea which is first second third or whatever. Pick one, resubmit and say ignore previous and we’ll take it out -Anthony

Don V
August 30, 2010 11:36 pm

Ignore all previous posts. I will reenter when I have time.

George E. Smith
August 31, 2010 6:23 pm

“”” Yuba Yollabolly says:
August 30, 2010 at 7:59 pm
Mr Smith- You are right. Clouds don’t heat. But they needn’t heat to be a feedback. All they need to do is to slow the rate of cooling. That is their tendency at night.
“Who says so?” – Any basic weather text book will tell you that.
Although you are also right “last night’s weather is not climate”, night happens about half the time and the aggregate effect is very important to climate. Furthermore night makes up half of “always”.
I have reviewed Wentz et al (2007)
What I find is a study that indicates that globally The hydrologic cycle appears to increase at a greater rate than climate models have predicted. I don’t see any part that refers to “precitable” clouds nor additional radiation absorbed by them.
I did notice these comments however:
“…both climate models and observations indicate that the total water vapor in the atmosphere increases by about 7% K^-1. “””
Well Yuba, I don’t think you reviewed Wentz, et al very carefully.
As you reported: “”” “…both climate models and observations indicate that the total water vapor in the atmosphere increases by about 7% K^-1. “””
But it is what you missed. Wentz et al also reported that Total Global Evaporation, and Total Global Precipitation ALSO increased by that same 7% per deg C increase in mean global surface Temperature. The GCMs on the other hand disagreed, saying those two only increase by from 1-3%. In other words the GCMs are in error by as much as a factor of 7 times from what Wentz et al OBSERVED to happen.
Now it is obvious that Total Global Evaporation and Total Global Precipitation must balance over time; or else we would end up with the oceans over our heads.
But the important point is that Total Global Precipitation goes up by 7% for a 1 deg C rise in Temperature.
I put it to you Yuba; A 7% increase in Total Global Precipitation might reasonably be expected to be accompanied by about a 7% increase in (precipitable) cloud cover. That increase could comprise an increase in cloud area, or an increase in cloud water content and Optical Density, or an increase in persistence time of the cloud; or some combination of all three. Yes you are correct that Wentz et all DID NOT mention any increase in precipitable clouds; I did that as an obvious corollary to their paper. So the discussion is quite open to anyone who accepts the truth of what Wentz et al reported in that paper to refute my corollary that must follow as a consequence of their results. If you have been reading WUWT diligently, you will probably have counted that it is about 20 times since July 7 2007 that I have pointed out this obvious consequence of the Wentz paper. (here at WUWT). They did not say it; I did !
It is not reasonable to postulate a 7% incerease in Total Global Precipitation; with no increase in clouds that are capable of precipitating that increased rain/snow/sleet/hail/whatever.
As for your observation that night time lasts about 50% of the time; daylight is well known to last for more than 50% of the time in total because of atmospheric refraction, that conveys sunlight to the surface even after the sun is geometrically below the horizon. But not to be nit picky; lets say half time daylight and half time night. The earth surface on average radiates 390 W/m^2 according to Trenberth. That number consists of a much lower value being emitted at night from the colder dark areas of earth for half the time; plus the much higher daytime rates of emission due to the sunlight hitting the surface, at a maximum rate of about 1000 W/m^2; so in fact the greatest cooling rate of the earth happens in the hoittest deserts during the highest temperature periods of daylight (T^4 effect)
Now throw in some Optics. The Sun is a near point source (1/2 degree divergence); so a cloud blocks the whole solar beam by whatever average optical transmission coefficient the cloud has depending on its water density; so it forms a quite distinct shadow zone; with a small 1/2 degree penumbral edge.
However the outgoing LWIR radiation is highly diffused; at least Lambertian (cos(theta)) for a smooth surface (water) and likely near isotropic for a rough surface. So the very same cloud that blocks some fraction of the total solar beam; only intercepts a small fraction of the diffuse LWIR; most of which misses the cloud; and the higher the cloud; the more radiation misses it.
So the cloud is very inefficient in intercepting the outgoing LWIR radiation; compared to its blocking of the incoming solar beam.
And lastly; those high clouds at night are not the cause of the warmer wetter surface; they are the result of it.
If the clouds were a feedback effect at night, the surface irradiance contributed by the cloud must diminish as the Fourth Power of the cloud height. I shouldn’t have to explain that but for sure somebody won’t get it.
The driving source of “heat” is the thermal radiation from the daytime heated surface. The irradiance of a cloud bottom from some radiating surface element that is illuminating the cloud at some inclined angle (theta) falls off as the square of the cloud height; and it also drops as Cos^4 (theta) for a Lambertian emitting source. (I (theta) = I (zero) Cos (theta) ) .
So the cloud irradiance from some surface elements goes as (1/H^2).Cos ^4 (theta). For an isotropic radiating surface the angular fallof is only Cos^3 (theta), but the value of I (zero) is much lower to start with.
So now the cloud may reflect some of the LWIR falling on it from our surface element; with whatever spectral reflectance it has; and it will also absorb some of the LWIR radiation; and eventually re-emit soem thermal radiation spectrum, about half of which will go up towards space, and half return to the ground.
The amount returning to our original source region will also suffer a (1/H^2) .Cos^4 (theta) attenuation. so the round trip loss is (1/H^4). Cos^8 (theta) .
Needless to say; not much of the surface emitted LWIR makes it back to where it started out. Sure some of it goes to some other spot; but that (1/H^4) is a killer, but the Cos^8 (theta) really rubs slat in the wound.
And according to all of those textbooks you mentioned; the higher the clouds are at night, the greater is the amount of “warming” they cause.
Well of course they don’t cause any warming at all. But as a result of the surface being warmer (at night) the higher the moist air has to rise before it reaches the dew point and forms those high clouds; which are the supposed reason the surface is warmer.
And if it is both warmer and less humid; then the dew point is even at a higher altitude. Yes those high clouds really play havoc with the (1/H^4) attenuation, and the Cos^8 (theta) obliquity factor.
So I suggest reading some different books, than the ones that say clouds are a positive feedback.
I loved these little gems:-
“”” You are aware the water vapor is a very significant GHG are you not Mr Smith?
Since most clouds do not rain I would say it is quite a jump to say “RAIN=CLOUDS”. “””
Well blow me down; I could swear that all the climate gurus say H2O is not a GHG but is a feedback factor that enhances CO2 warming. Now you are trying to tell me that H2O is a GHG. So why doesn’t the EPA regulate that as a dangerous pollutant too. Specially since our cars emit more H2O than they do CO2; and there is nowhere in the troposphere where CO2 ever exceeds H2O; maybe at Vostok in the dead of winter midnight that could be possible; that’s when the surface emitted LWIR emittance is more than a factor of six times lower than it is for the global mean surface temperature; so not much LWIR radiation to intercept.
But back to the GHG thing.
I do agree with you on this; H2O IS a GHG, and not the “weak” one that the late Stephen Schneider claimed it is (compared to CO2).
But then H2O also has this other property. It also intercepts a significant fraction of the incoming solar spectrum energy starting at about 750 nm wavelength and then in multiple bands out to the 4 micron range beyond which only 1% of the solar energy resides. But the 750 ->>> portion is about 45% of the total solar spectrum, and when you look at the water bands, it is easy to see where H2O could easily absorb as much as 20% of the solar energy. That’s the main reason why the air mass one ground level insolation is only 1000 W/m^2 instead of 1366 W/m^2
So not only does H2O as a vapor have atmospheric warming potential as a result of absorbing LWIR surface emitted thermal radiation; but it can cause additional atmospheric warming due to the absorption of that incoming 750 nm -4.0 micron solar energy. And of course what solar radiation is absorbed by H2O in the air, does not reach the ground; so it cools the ground.
Now true; to the extent that that captured solar energy warms the air and increases the thermal radiation from the atmosphere; that radiation is emitted isotropically; so only a half of it is directed towards the earth to ultimately warm the surface; the other half escapes to space. Well maybe more than half escapes; because the higher less dense cooler atmospheric layers (and H2) molecules) result in narrower absorption bands; compared to those of the lower denser hotter layers; so the upwards escape route is favored over the downward surface destination route.
And lets not forget that without the water vapor; what reaches the surface (say ocean) is “short” wave solar spectrum radiation; which propagates deeply into the ocean maybe several hundred metres, and warms it; but the surface directed downward LWIR radiation that the atmosphere substitutes for that solar energy (half of it) is absorbed in the top 10 microns of the ocean surface (mostly) and that results in prompt evaporation of even more of that GHG water vapor H2O.
But this last one is a doozy:- “”” Since most clouds do not rain I would say it is quite a jump to say “RAIN=CLOUDS”. “””
Read it again; I said “RAIN = CLOUDS” I DID NOT say RAIN = CLOUDS. So I agree with you; most clouds do not rain; which the cognoscenti might interpret as the precise reason why I actually used the term “PRECIPITABLE CLOUDS”; meaning that portion of the global cloud cover which is capable of resulting in precipitation.
Now I am quite happy to entertain any research results you care to report of any significant amounts of Precipitation of the rain/snow/sleet/hail/whatever, variety that you have observed in the total absence of clouds.
And I will repeat my assertion; warm humid nights following even warmer humid days may result in high clouds forming; the reverse does not happen (high clouds causing warm humid surface temperatures).
H2O; Water, is the only GHG that is a permanent component of the earth’s atmospehre in ALL THREE of its phases of ordinary matter, gas/liquid/solid.
As a vapor it has atmospheric warming properties as a result of both LWIR thermal radiation absorption and also direct absorption of a significan portion of the incoming solar spectrum. The former may also tend to warm the surface; but the latter cools the surface.
But in the other two phases as liquid or solid clouds, H2O acts to cool the surface. Nobody ever observed the surface Temperature to increase in the shadow zone, when a cloud passes in front of the sun; it always gets cooler.
Regardless of what CO2 or TSDI variations or any other GHG attempts to do to change the mean temperature of the earth; the stable comfortable temperature regime is maintained by feedback regulation due almost entirely to the Physical and chemical Properties of H2O. Yes I am sure there are biological effects as well; but the melting point, and boiling poiint, the phase change latent heats; the specific heats; the molecular absorption spectra, the bulk optical absorption spectra, the Clausius-Clapeyron equation, and on and on, are the things that control the earth’s average Temperature. So long as the oceans persist; we could not significantly change the temperature of this planet; either up or down; even if we wanted to.
And suppose we could; What Temperature would you set it to; and WHY !!

Yuba Yollabolly
August 31, 2010 7:25 pm

Well Mr smith I guess I did read Wentz more carefully than you did because according to them precipitation (the hydrologic cycle) increased by 6% per K and not 7% as you stated.
My statement still stands and you have produced nothing to disprove it. Stop fighting straw men and falsely accusing me.
But continue to rant on if you like.
yuba

Steve Koch
September 10, 2010 4:19 pm

Mikael Pihlström:
“Had S&B been able to unequivocally show that positive feedbacks are not important they would have broken through any review-barrier, hostile or not. They could not do so and the question remains: what’s so revolutionary about this work?”
Sometimes the perfect is the enemy of the excellent. Spencer did show that the current feedbacks are negative and weaken even more the very tiny direct warming effect of doubling CO2. While he did not disprove the possibility of long term stronger feedbacks, the current negative feedback to the direct CO2 forcing does not inspire confidence that there will be long term larger warming feedbacks. Spencer does not have to disprove that long term feedback from a CO2 increase will be much greater than short term feedbacks. Anybody claiming larger long term feedbacks needs to prove his point with real data.
What is great about Spencer’s work is that it is based on actual real data from real sensors. Believe it or not, that is much more persuasive than predictions from models. BTW, of course Spencer is going to be more cautious in an academic paper than on a popular blog because the target audiences are so different.
Spencer’s finding that the measured feedback from doubling CO2 is 0.6 deg. C undermines the arguments of alarmists who have models that predict feedbacks that are up to an order of magnitude larger.
WRT the political debate about cap and trade in the USA, the timing of this paper is perfect.

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