Guest Post by Willis Eschenbach
Like anyone else, I’m not fond of being wrong, particularly very publicly wrong. However, that’s the price of science, and sometimes you have to go through being wrong to get to being right. Case in point? My last post. In that post I looked at what is known as “net cloud radiative forcing”, and how it changed with surface temperature. Net cloud forcing is defined as the amount of downwelling upwelling longwave radiation (ULR, or “greenhouse radiation”) produced by the cloud, minus the amount of solar energy reflected by the cloud (upwelling shortwave radiation, or USR). If net cloud forcing is negative, it cools the earth below.
I found out that indeed, as temperature goes up, the net cloud radiation goes down, meaning the clouds have a greater cooling effect. I posted it, and asked for people to poke holes in it.
What could be wrong with that? Well, I forgot a very simple thing, and none of the commenters noticed either. The error was this. Net cloud forcing is cloud DLR ULR minus shortwave reflected by that same cloud. But what I forgot is that reflected shortwave is the cloud albedo times the total insolation (downwelling solar shortwave radiation).
The catch, as you probably have noticed, is this. If the cloud doesn’t change at all and the total insolation rises, the net cloud forcing will become more and more negative. The upwelling reflected solar is the cloud albedo times the insolation. As insolation rises, more and more sunshine is reflected, so the net cloud forcing goes down. That’s just math.
The problem is that as insolation rises, temperatures also rise. So by showing net cloud forcing goes down with increasing temperature, all I have done is to show that net cloud forcing goes down with increasing insolation … and duh, the math proves that.
However, recognizing that as the problem also gave me the solution. This is to express the net cloud forcing, not as a number of watts per square metre, but as a percentage of the insolation. That way, I could cancel out the effect of the insolation, and extract the information about the clouds themselves. Figure 1 shows the results of that analysis.
Figure 1. Net Cloud Forcing (W/m2) as a percentage of gridcell insolation (W/m2), monthly averages from 1985-1989. Average percentage results shown above each map are area-averaged. Missing data shown in gray. Cloud forcing data from ERBE, insolation data from NASA.
This is an interesting result, for a variety of reasons.
First, it is quite detailed, which gives me confidence in the geographical accuracy of my calculations. For example, the cooling effect of the thunderstorms in the Inter-Tropical Convergence Zone (ITCZ) is clearly visible in the Pacific as a horizontal blue line slightly above the equator, and can be seen in the Atlantic Ocean as well. The ITCZ is the great band of equatorial thunderstorms around the planet that drive the Hadley circulation. Remember that the majority of the energy entering the climate system is doing so in the Tropics. Because of that, a few percent change in the equatorial net cloud forcing represents lots and lots of watts per square meter.
Second, the differing responses of the clouds over the land versus clouds over the ocean are also clearly displayed. In general, land clouds warm more/cool less than ocean clouds. In addition, you can see that while the clouds rarely warm the NH ocean, they have a large warming effect on the SH ocean.
Third, and most significant, look at the timing of the seasonal changes. Take December as an example. In the Northern Hemisphere this is winter, the coldest time of year, and the clouds are having a net warming effect. In the Southern Hemisphere summer, on the other hand, clouds are cooling the surface. But by June, the situation is reversed, with the clouds having a strong cooling effect in the warm North, while warming up the winter in the South. (Note that the NH warming effect is somewhat masked by the fact that there are large areas of missing data over the land in the NH winter, shown as gray areas. The effect of this on the global average is unknown. However, by using a combination of gridcells which are adjacent temporally and gridcells which are adjacent spatially, it should be possible to do an intelligent infill of the missing areas and at least come to a more accurate estimate of the net effect. So many paths to investigate … so little time.)
I have hypothesized elsewhere that the earth has a governor which works to maintain a constant temperature. One of the features of a governor is that it cannot be simple fixed linear feedback. By that, I mean it must act in two directions—it must act to warm the earth when it is cold, and to cool the earth when it is warm. This is different from linear negative feedback, which only works to cool things down, or linear positive feedback, which only works to warm things up. A governor has to swing both ways.
Figure 1 clearly shows that, as I have been saying for some time, including both the longwave and shortwave effects clouds act strongly to warm the earth when it is cold (red areas in Figure 1) and to cool the earth when it is warm (blue areas in Figure 1). In addition, as I have also said (without much evidence until now to substantiate my claim), the ITCZ has a large net cooling effect.
So that’s where I am up to right now in my investigation of the ERBE data. Always more to learn, I’ll continue to report my results as they happen, the story of the ERBE data is far from over. I’ll be in and out of contact for a bit, I’m around today but I’m hitchhiking up to Oregon tomorrow for a friend’s bachelor party, so don’t think I’m ignoring you if I don’t answer for a bit.
w.
PS – there are some interesting results that I’ll post when I have time. These involve looking at the phase diagrams for cloud forcing, temperature, and insolation. Having the insolation available allows the phase of both the temperature and the forcing to be compared to what is actually the underlying driving mechanism, the insolation.
Regarding temperature and insolation, the ERBE data shows what is well known, that the temperature changes lag the insolation changes by about two months in the Southern Hemisphere, and by one month in the Northern Hemisphere. This is because of the thermal inertia of the planet (it takes time to warm or cool), along with the greater thermal inertia of the greater percentage of ocean in the south.
The interesting part is this: the phase diagram shows that there is no lag at all for the changes in the clouds. They change right in step with the insolation, in both the Northern and Southern Hemispheres.
This means, of course, that the clouds move first, and the temperature follows.
I’ll post those phase diagrams when I have some time.
[UPDATE: The phase diagrams, as mentioned. First, Figure 2 shows the temperature versus the insolation:
Figure 2. Insolation vs absolute temperature, from the equator to 65 N/S. The poles are not included because the ERBE cloud data only covers 65 N/S. This does not affect the phase diagrams. Black line shows no lag, gold line shows one month lag, red line shows two months lag between maximum insolation and maximum temperature. Numbers after month names show months of lag.
Since the driving signal (insolation) peaks in June and December, those months will be in the corners when the two cycles are aligned. In the Northern Hemisphere (upper panel), December is in the lower left corner with a lag of 1 month (gold line).
The Southern Hemisphere is half a cycle out of phase, so December is maximum insolation in the upper right corner. This occurs with a lag of two months (red line).
This verifies that temperatures lag insolation by a month in the Northern Hemisphere (the warmest time is not end June, when the insolation peaks) and two month in the southern hemisphere.
However, the situation is different with the clouds, as Figure 3 shows.
Figure 2. Insolation vs cloud forcing %, from the equator to 65 N/S. The poles are not included because the ERBE cloud data only covers 65 N/S. I suspect that the odd shape is a consequence of the missing gridcell data in the ERBE dataset, but that is a guess.
For the cloud forcing in both Hemispheres, there is no lag with regards to the insolation.
w.
GabrielHBay says:
October 12, 2011 at 5:21 am
[SNIP – that is nothing but a vicious personal attack without a scrap of scientific content. Take it elsewhere. -w.]
Septic Matthew says:
October 12, 2011 at 11:06 am
Ugh. This is the kind of scientific illiteracy that inspires praise for Eschenbach.
Clouds are not water vapor. Water vapor is a colorless transparent gas. Clouds are composed of water droplets. Write that down.
@ckrucible: Well, I think we should stop this dead-end discussion before we irritate the s**t out of the scientific community here. A quick google delivers this document, which, while just an example, does seem to indicate that the idea of warm (enough) clouds to cause warming seems (ahem) a trifle outlandish.
http://www.gma.org/surfing/weather/francloud.pdf
Probably wise to abort this line of thinking and just accept that clouds are just insulators in their nett effect, slowing down cooling but not actively warming.
davidmhoffer says:
October 12, 2011 at 9:44 am
Get a clue, Hoffer. Science offers explanations for observations. The sky is blue is an observation. Science explains why the sky is blue. What I described were observations.
Everyone is entitled to their own opinions but not their own facts. ~US Senator Daniel Moynihan
@Septic Matthew: I quote from your entry: “Everything takes time. As the unfrozen water vapor in the cloud cools by radiation, it warms the earth, and settles down as dew.”
Not being a climate scientist but merely engineering educated I am clearly far too ignorant to understand this sentence. (On the assumption that you are climate educated? No?) Well I give up. Am trying to understand your reasoning but failing. Shame on me… Enough already.
Willis Eschenbach says:
October 12, 2011 at 1:17 am
“Interesting catch, Legatus. My guess is trade winds blowing towards the west plus subsurface eastward-flowing currents hitting south america/africa cause year-round upwelling, but we’re a ways into speculation there.”
Not quite, Both these areas have cold currents coming from the south (Benguela/Humboldt currents), and the ocean is always much colder than the nearby land. Both areas are well-known for practically constant and unchanging low cloudiness. The warmer land causes a more or less constant sea-breeze, but the clouds evaporate as they cross the coast, so the coastal areas (Namib desert, Atacama desert) are just about the driest places on Earth. Along the very coastline it is very often foggy with an occasional very fine drizzle, but it never, ever rains. Quite weird really.
Another interesting observation is the very strong cooling over the Southen Ocean in the zone between Antarctica and the Southern Continent during 8 of the 12 months of the year. It has long been known that the Earth’s temperature dropped dramatically in the Early Oligocene when Antarctica became separated from Australia and South America and Australia and a circum-Antarctic seaway opened. This has usually been ascribed to Antarctica becoming thermally isolated and heavily glaciated for the first time, but these maps suggest a further cooling mechanism.
[SNIP – if you want to debate basic principles, do it elsewhere. -w]
@Dave Springer: Thank you. A small recovery in my faith in my own sanity…..
Dave Springer;
Get a clue, Hoffer. Science offers explanations for observations. The sky is blue is an observation. Science explains why the sky is blue. What I described were observations.>>>
Really? You described observations? Allow me sir, to quote your own words back to you:
“There IS a tipping point for the earth’s climate but the tipping point is from comfortably warm to unbearably cold. These are the facts and they are, being observed facts not theoretical predictions, beyond dispute.”
You have postulated a tipping point from warm to cold and stated that it is an “observed fact” that it is “not theoretical” and that it is “beyond dispute”. Can you back that up with the actual observations that you claim? Can you show through the scientific analysis of those observations that a “tipping point” exists that is borne out by the physics and chemistry involved? Can you explain the physical and chemical processes, and show that the mathematical analysis of the observational data is in agreement?
Or do we just take your word for it because you say it is “beyond dispute”? Are you a mirror copy of Michael Mann or something?
About all this “cloud make a cold day warmer…
Well, how did the cloud get there, and how did it get to be a cloud anyway?
To have a cloud in the first place, you have to have evaporation, and that takes heat. For that cloud to move from where it formed to the cold clear place you are at, there has to be wind.
So when the cloud arrives, it tends to bring the warmer air with it, that moving air being how it gets there after all.
Thus the anecdotal evidence of clouds warming the formerly cold area may simply be that the clouds arrived with warmer air, and thus you feel the warmth of the warmer air that has moved in.
This of course is not taking into effect other things that can cause warming, high pressure areas being one.
As for the man under the blanket, the analogy is more like this:
It is not a man, it is a corpse, it has no heat of it’s own.
Above the corpse is a heat lamp.
This lamp is turned off and on every 12 hours, turning slowly on till it is at full intensity 6 hours in (noon), and slowly off for 6 hours till it is completely off 6 hours from noon (or a bit later/earlier).
Having a blanket will thus tend to hold the heat that the lamp added to the corpse in longer (and add a little of it’s own that it also absorbed).
The original analogy does not match the earth and clouds, because it is the man that is the source of the heat, and thus having a heat producing man under a blanket will of course lower his heat transfer out (by radiation and convection).
Dave Springer;
“It’s laughable yet the cheerleaders in these comments who are more or less equally ignorant lavish him [Willis Eschenbach] (and a few other scientifically illiterate authors here) him with praise… I kind of wonder what the relationship is between Eschenbach and Watt that this is allowed to continue…”
I doubt that either Anthony Watt or Willis Eschenbach will stoop to your level and respond to that tirade, but I’m a good stooper. Allow me to explain why Willis has such a huge fan base here.
1. I’ve never seen him make a mistake that he didn’t instantly own up to when it was pointed out.
2. The vast bulk of his opinions are borne out by investigation to be factual and accurate.
3. He conducts himself with dipliomacy at all times, even when responding to the most egregious of insults questioning everything from his sanity to his honesty despite the fact that he posts all the reasoning and data to support his arguments for all to see.
4. I’ve lost about 20 arguments about science in my lifetime where I was shown to be dead wrong and 19 of them were with Willis. Not once did he gloat.
5. I actually won an argument with Willis once. Just once. He proved to me that, contrary to my long held belief, weasels do not kill for sport. Tough for me to take as having grown up on a farm I’ve seen what happens when a weasel gets into a chicken coop. As usual however, Willis was right. His only mistake was that he called it an urban legend. As I pointed out to him at the time, it was actually a rural legend. Small victory, but how many people can say they won an argument with Willis and cracked him up doing it?
There have been several absolutely stellar articles on this blog published in response to the nonsense of PNS, a strongly worded rebuttal to Judith Curry that was shear genius, and many others. I’ma pretty decent writer myself, but I’m not in Willis’ league. I can choose to try and pull myself up by pulling him down, or I can choose to admire and honour his work. I choose the latter.
You are free to choose what you will, but don’t be so quick to judge others based on anecdotal evidence. A good observer with hands on experience in the real world and a fundamental understanding of the underlying physics beats a PhD in just about anything when it comes to understanding and solving complex problems. The smartest man I ever knew (sorry Willis, even smarter than you) had a grade 6 education and made his living as a welder and machinist. He once built a piece of equipment for use in the oil fields that, due to his strong religous beliefs, he decided was a bad thing and he cut it to pieces, much to the chagrine of the investors who funded it and the oil companies that were lined up around the block with purchase orders. I remember an PhD in mechanical engineering from Shell going through the pieces trying to put them back together. He showed me a valve that had the most curious channels cut in it. He said to me he couldn’t figure out what they did in the first place, but even if he understood it, he couldn’t figure out how to machine a hole that tapered back and forth through the material like that.
You see Dave Springer sir, swimming in the ocean doesn’t teach you squat about the ocean. Swimming in the ocean, making carefull observations, and investigating them to obtain a more detailed understanding of them teaches you about the ocean. Someone who had never done the swimming, is only relying on the word of others. They know nothing for themselves.
“Thus the anecdotal evidence of clouds warming the formerly cold area may simply be that the clouds arrived with warmer air, and thus you feel the warmth of the warmer air that has moved in.”
Precisely.
[SNIP – How many times do I have to say it. TAKE YOUR CLAIMS ABOUT DLR ELSEWHERE. This is not the thread for them. They may be true, they may not be, but they are definitely far, far off topic. w.]
Willis Eschenbach says:
October 11, 2011 at 5:12 pm
” Clouds warm the surface when it is cold, and they cool the surface when it is hot.”
“The way I make sense of it is that the clouds respond on a minute-to-minute basis to the daily fluctuations in temperature. This is different from the slow warming and cooling of the seasons.”
__________
A good article Willis. Version two is better. I appreciate you trying to quantify what I have known from direct observation to be true.
I would add: “…clouds respond on a minute-to-minute basis to the daily fluctuations in temperature”, the Temperature-Dewpoint spread, Relative humidity and Atmospheric pressure.
The complexity derives from the total enthalpy of the system, not just the radiative balance. How to separate them out I’ll never know.
.
[SNIP –“You’re beginning to bore me, dopey.” .w]
Dave Springer: Clouds are not water vapor.
I didn’t say they were. I said that there is water vapor in the clouds. Are you asserting that every single water molecule joins a droplet? And that the water vapor condenses without transmitting energy?
GabrielHBay Not being a climate scientist but merely engineering educated I am clearly far too ignorant to understand this sentence.
Are you being ironic? It’s hard to tell sometimes. Poe’s Law, I think.
well said davidmoffer
I back willis even though I am a climate ignoramus. Because I recognise integrity.
Caveat – I have been known to laud CAGW freaks who show integrity (yes , there are some :))
[SNIP – David, your ad hominem attacks on me are puerile and unpleasant. -w.]
Septic Matthew says:
October 12, 2011 at 2:48 pm
“I didn’t say they were.”
Yes, you did.
“I said that there is water vapor in the clouds.”
There is water vapor everywhere in the troposphere, Matthew. There’s actually far less of it in the clouds than outside the clouds because because the dew point has been reached inside the cloud and most of the water vapor has condensed into liquid water. If that weren’t the case there would be no cloud to see.
“Are you asserting that every single water molecule joins a droplet?”
No. But compared to the air outside of a cloud there is less water vapor in the cloud than outside the cloud.
” And that the water vapor condenses without transmitting energy?”
Water releases a tremendous amount of energy when it changes phase from vapor to liquid. About a thousand BTU’s per pound actually and it releases all the energy without changing temperature. It takes about a thousand BTUs to turn one pound of water at 212F into one pound of steam at 212F. One BTU is the amount of energy required to raise the temperature of one pound of water one degree F.
Septic Matthew says:
October 12, 2011 at 9:48 am
When that happens we call it convection, and the conveyed heat is latent, already in the system, and delivered by the sun. If insulators did indeed heat things then I could heat my house by stuffing a large box of blankets in each room. Who needs a furnace?
I admire Willis greatly but I have a problem in scientific discussions when these language problems go unchecked. That said, the language does not impact the underlying message Willis is sharing and which I find fascinating.
@Dave Springer
i believe you have things right.
i also think that willis’ thunderstorm thermostat argument has its strength where it agrees with what you’re saying about phase change and convection and blocking/absorbing of radiation.
Richard Courtney :
Rob : “Willis, are yyou are still confused. ”
and “you keep on using the wrong definition of “cloud forcing”. ”and “As I pointed out, your conclusion is incorrect as a result of your now abundant amount of mistakes.”
My question is; Are you joking or dissembling?
Richard, you can check for yourself who is joking or dissembling : Let’s go to the landmark paper that first used ERBE to determine cloud forcing (which Willis interestingly did NOT reference) : http://www.iac.ethz.ch/edu/courses/master/modules/radiation_and_climate_change/download/Ramanathan1989
Check how Ramanathan defines “cloud forcing” so we can tell if clouds warm or cool the planet. Then compare that to Willis’ definition.
Next, note that ERBE (as a satellite) measure space-bound IR, and not “downwelling longwave radiation” as Willis suggests. And then check how Willis get completely confused with between cloud forcing and cloud feedback, to the point where he believes that by dividing by the insolation you magically get from one to the other.
Of course, Willis’ conclusions are irrelevant and also contradict the findings by Ramanathan’s and all other scientific papers determining feedback or forcing from ERBE data.
Let me note that Willis is not the only one confusing cloud forcing with cloud feedback. Even our host Anthony got a bit wrapped around the axle in a recent post on exactly the same subject
http://wattsupwiththat.com/2011/09/20/new-peer-reviewed-paper-clouds-have-large-negative-feedback-cooling-effect-on-earths-radiation-budget/
There, he was corrected by Bart Verheggen and Roy Spencer, and Anthony admitted his mistakes and and promised a correction : “Yep, that was a late night blunder. I’m rewriting the entire post while wide awake.”
Would be nice is Willis could do the same with this post.
Eternal Optimist says:
October 12, 2011 at 3:09 pm
well said davidmoffer
“I back willis even though I am a climate ignoramus. Because I recognise integrity.”
A livestock guard dog is an animal with such high integrity it would make a saint seem evil. All the integrity in the world won’t get you a passing grade on an algebra test. What’s your point?
@Dave Springer,
Most of us here just want to have a reasoned discussion. This has nothing to do with thinking Willis is “king” or like a “god” or anything of that nature. In fact I argued with him quite a bit on previous threads, just because I am taking the side of the analysis in this case means nothing. When you are discussing things that really do not matter, I mean in this case it is nothing but a hypothesis that seems like it has promise…well in that case it might mean something but for now not really anything.
Why do I like reading his articles (even if I disagree with some of em…)? Well because as the other Dave says, he admits when he is wrong! Look at the title of this article!
In other words, no, I am not fawning over him and I doubt many people are out of any misguided belief that we must bow down to him because he is a sceptic or some other nonsense like that.
I think most of us think proper respect is appropriate perhaps, but nothing other then that. There are other people who post here that I might disagree with as well and yet I will still be respectful for the most part.
So in other words, can we discuss the actual article perhaps? Even Rob’s pointless remarks are better then that. Ad-homs are something I see enough of from warmist fools, can we keep it civil?
Dave Springer says:
October 12, 2011 at 4:47 pm
————————————————–
I’m just guessing Dave but the point would be “guard-dog” Eternal Optimist thinks you have less integrity than Willis, doesn’t fully understand climate science (which is true of most of us) and therefore believes Willis to a greater extent than you.
It doesn’t make Eternal Optimist an ignoramus, but merely points out he/she is willing to follow Willis and his arguments as EO attempts to better understand the science.
Integrity is how some people gain an audience and how others end up in a crowd of one.