Guest Post by Willis Eschenbach
I read a Reviewer’s Comment on one of Richard Lindzen’s papers today, a paper about the tropics from 20°N to 20°S, and I came across this curiosity (emphasis mine):
Lastly, the authors go through convoluted arguments between forcing and feed backs. For the authors’ analyses to be valid, clouds should be responding to SST and not forcing SST changes. They do not bother to prove it or test the validity of this assumption. Again this is an assertion, without any testable justification.
Now to me, showing that clouds respond to the tropical surface temperatures, either on land or sea, is a no-brainer, I’m surprised that the Reviewer would question it. But before I discuss that, let me digress for a moment to say that I think there are two simple changes in the reviewing process that would help it immensely.
1. Double blind reviewing. Right now, reviewing is just single blind, with the reviewer knowing the identity of the author but not the other way around. This is a huge, huge violation of the scientific norms, and it leads and has led to problems. A recent proposal to use double-blind reviewing in the awarding of grants by the National Science Foundation makes for interesting reading … http://www.nsf.gov/nsb/publications/2011/meritreviewcriteria.pdf This would put the focus back onto the ideas rather than the author.
2. Publish the reviews and the reviewer’s names along with the paper when it is published. This sunshine, this transparency, will have several benefits. First, if a reviewer still has strong reservations about the paper, or if their objections have led to improvements or changes in the paper, this will be made visible when the reviews are published (presumably online) along with the paper. Second, we get to see who agrees that the paper is valid science, and who might not. Third, in the fullness of time, we will have a record of who was right and who was wrong. But I digress … the anonymous Reviewer wanted Lindzen to show that clouds respond to SST.
Not having read Lindzen’s paper, I don’t know what he said about the question. But for me, Figure 1 should convince even the most alarmist reviewer that clouds are responding to the surface temperature, both on land and over the ocean.
Figure 1. Monthly albedo averages from ERBE. Images show the N/S range of the geographical tropics (~ 23.5° N/S). Thin black horizontal line shows the Equator.
The upper panel shows the albedo for August (northern hemisphere summer) and the lower panel for February (southern hemisphere summer). The brighter areas show the regions with higher albedo, because there are more clouds. There are some things of note in the figure.
For example, look at Brazil and the Amazon in the lower panel (the bright spot in the lower left of the panel, below the Equator.). In February, in the southern summer, the heat creates lots of clouds. But in the upper panel, the southern hemisphere winter, Brazil has a much lower level of clouds.
The same thing is true about southern Africa. In the southern summer (lower panel) the albedo is high in southern Africa, with lots of clouds. In the southern hemisphere winter (upper panel), on the other hand, southern Africa loses its clouds, and above the Equator where it is summer we see increased albedo in the northern part of Africa.
Next, tropical Asia in August, when it is warm, has lots of clouds. But when winter comes, the clouds move with the summer down to the southern hemisphere.
Similar changes are generally occurring over the oceans as well, but in a more muted fashion. Again, this difference in effect shows that surface temperature is the driving factor, since the land temperatures change more with the seasons than do the ocean temperatures.
Now, we have three choices here:
1. Tropical clouds are increasing and decreasing in response to the changes in surface temperature resulting from the sun’s motion, which alternately warms the areas north of and south of the Equator, or
2. The clouds are just coincidentally in sync with the sun by random chance, or
3. The clouds are making the sun move north and south of the Equator.
Your choice, but to me, that should satisfy even the most recalcitrant reviewer. It’s clear that the clouds are responding to the variations in surface temperature, with more clouds forming as the surface warms and less clouds when the surface is cooler.
w.
PS: Since we’re discussing clouds as forcing and feedback, you’ll excuse me if I take this opportunity to re-post the following from my “Thermostat Hypothesis” paper. In it I am describing how the clouds and thunderstorms work as a governor to stabilize the temperature:
The problem with my thought experiment of describing a typical tropical day is that it is always changing. The temperature goes up and down, the clouds rise and fall, day changes to night, the seasons come and go. Where in all of that unending change is the governing mechanism? If everything is always changing, what keeps it the same month to month and year to year? If conditions are always different, what keeps it from going off the rails?
In order to see the governor at work, we need a different point of view. We need a point of view without time. We need a timeless view without seasons, a point of view with no days and nights. And curiously, in this thought experiment called “A Day In the Tropics”, there is such a timeless point of view, where not only is there no day and night, but where it’s always summer.
The point of view without day or night, the point of view from which we can see the climate governor at work, is the point of view of the sun. Imagine that you are looking at the earth from the sun. From the sun’s point of view, there is no day and night. All parts of the visible face of the earth are always in sunlight, the sun never sees the night-time. And it’s always summer under the sun.
If we accept the convenience that north is up, then as we face the earth from the sun, the visible surface of the earth is moving from left to right as the planet rotates. So the left hand edge of the visible face is always at sunrise, and the right hand edge is always at sunset. Noon is a vertical line down the middle. From this timeless point of view, morning is always and forever on the left, and afternoon is always on the right. In short, by shifting our point of view, we have traded time coordinates for space coordinates. This shift makes it easy to see how the governor works.
The tropics stretch from left to right across the circular visible face. We see that near the left end of the tropics, after sunrise, there are very few clouds. Clouds increase as you look further to the right. Around the noon line, there are already cumulus. And as we look from left to right across the right side of the visible face of the earth, towards the afternoon, more and more cumulus clouds and increasing numbers of thunderstorms cover a large amount of the tropics.
It is as though there is a graduated mirror shade over the tropics, with the fewest cloud mirrors on the left, slowly increasing to extensive cloud mirrors and thunderstorm coverage on the right.
After coming up with this hypothesis that as seen from the sun, the right hand side of the deep tropics would have more cloud than the left hand side), I though “Hey, that’s a testable proposition to support or demolish my hypothesis”. So in order to investigate whether this postulated increase in cloud on the right hand side of the earth actually existed, I took an average of 24 pictures of the Pacific Ocean taken at local noon on the 1st and 15th of each month over an entire year. I then calculated the average change in albedo and thus the average change in forcing at each time. Here is the result:
Figure 2. Average of one year of GOES-West weather satellite images taken at satellite local noon. The Intertropical Convergence Zone is the bright band in the yellow rectangle. Local time on earth is shown by black lines on the image. Time values are shown at the bottom of the attached graph. Red line on graph is solar forcing anomaly (in watts per square meter) in the area outlined in yellow. Black line is albedo value in the area outlined in yellow.
The graph below the image of the earth shows the albedo and solar forcing in the yellow rectangle which contains the Inter-Tropical Convergence Zone. Note the sharp increase in the albedo between 10:00 and 11:30. You are looking at the mechanism that keeps the earth from overheating. It causes a change in insolation of -60 W/m2 between ten and noon.
Now, consider what happens if for some reason the surface of the tropics is a bit cool. The sun takes longer to heat up the surface. Evaporation doesn’t rise until later in the day. Clouds are slow to appear. The first thunderstorms form later, fewer thunderstorms form, and if it’s not warm enough those giant surface-cooling heat engines don’t form at all.
And from the point of view of the sun, the entire mirrored shade shifts to the right, letting more sunshine through for longer. The 60 W/m2 reduction in solar forcing doesn’t take place until later in the day, increasing the local insolation.
When the tropical surface gets a bit warmer than usual, the mirrored shade gets pulled to the left, and clouds form earlier. Hot afternoons drive thunderstorm formation, which cools and air-conditions the surface. In this fashion, a self-adjusting cooling shade of thunderstorms and clouds keeps the afternoon temperature within a narrow range.
Willis: In Figure 1, what is the time period for Figure 1? Is that a specific year or are those the February and August averages for a time period?
Thanks Willis. I entirely agree on double-blind peer review – that should cause the ‘pal-reviewers’ some problems.
As a complement to your work on cloud coverage, the average height of clouds has also been in the frame:
http://thegwpf.org/science-news/5052-global-warming-may-be-held-back-by-falling-cloud-levels.html
Cue Joni Mitchell…
Having lived and worked in the tropics I can say that convective clouds form over both ocean and land. Ocean formed convective cloud forms slower than land formed but still gives afternoon thunder storms, though not every day in the Maldives. Night time clouds did continue to form, and give rain, but this declined over night as the surface temperature cooled.
Having flown through the ITCZ several times I can confirm that it contains some very energetic convective clouds climbing to well over 70,000ft (21,336m). It would seem that the old claim that Cb clouds stopped building at the tropopause is wrong for the ITCZ.
This is a nice example on how by emphasizing a part of a sentence you can completely change its meaning. Are you really sure it wasn’t the “and not forcing SST changes” what the author considered important?
Apart of that, I kinda disagree that clouds respond to surface temperatures. Assuming constant supply of condensation nuclei, clouds respond to evaporation and evaporation is in fact negative feedback on surface temperature change – you get way more evaporation and way less temperature differences on sea than on land, for example.
Two excellent points.
The first one about double blind review is so damn obvious I am ashamed it never crossed my mind.
Admittedly it might get tricky because of possible references within a paper back to earlier works of the author(s), but this is no excuse not to try.
Tiddly Typo: Brazil has a much lower leven of clouds.
[Mind you, unleavened clouds conjures up some very nice imagery. Maybe you should leave it as it is!]
[Thanks, fixed, and I do like the idea of unleavened clouds … -w.]
I agree with pretty much all that but suggest that it is only part of the story.
The level of solar activity also changes the air circulation from the top down by processes not yet fully understood and that modulates the cloud response to SSTs on much longer timescales than the annual seasonal variation.
Longer even than the ENSO cycle and the 60 year Pacific Multidecadal Oscillation. Most likely on timescales between MWP and LIA and the present.
Climate change is the netted out consequence of the bottom up SST effects and top down solar effects both of which combine to alter surface air circulation globally and thus global albedo.
I also agree with Kasuha in that the rate of evaporation is at least as important as raw SST since water vapour is lighter than air and provokes additional convection without the need for any increase in the surrounding temperature.
In fact I think the apparent ‘lid’ on tropical SSTs that Willis has previously drawn to our attention is set at the point where the rate of evaporation rises to a level where convective uplift from the amount of water vapour present starts to exceed uplift from surface temperature alone.
I live in the ITCZ and its great fun, especially in peak periods, landing or taking off, in a jumbo jet wondering if you will make it.
The jungle retains vast amounts of moisture and due to its multilayer structure, has possibly far larger surface area than ocean to facilitate evaporation. Thus the rapid formation of storms over land as opposed to those growing over oceans .
It never ceases to amaze me how,at times, it can seen to suddenly get hotter at night. Usually occurs before night time rain. Perhaps indicative of humidity rising.
Watching, massive thunderbolts strike to road and trees just feet away from you reminds you strongly of your mortality. I saw a banana copse, across the road literally explode and get strewn all over the road, when struck by lightening.
Willis>
Is double-blind reviewing possible? I would have no trouble picking your writing from Anthony Watts’ or Steve McIntyre’s, let alone that of some of the alarmists, whether it has your name on it or not..
Dave says (June 7, 2012 at 4:50 am)
Is double-blind reviewing possible? I would have no trouble picking your writing from Anthony Watts’ or Steve McIntyre’s..
——————–
Ah, but then S. Mosher and others had no trouble picking out Peter Gleicks writing from the fake memo, but apparently “he didn’t write it – official”. 😉
Willis
What if clouds show BOTH feedback AND forcing? e.g., forcing via Svensmark’s cosmic ray hypothesis?
How do we distinguish and quantify each?
With solar driving ocean temperature, note David Stockwell’s solar accumulation theory predicting a Pi/2 (90 deg) lag from solar forcing to ocean temperature response. e.g., 2.75 years for the 11 year Schwab cycle. Projecting tot he annual cycle suggests a 3 month lag from solar max/min to ocean temperature max/min. Presumably there should be a corresponding lag in clouds responding to temperature lagging solar forcing.
Recommend checking how cloud albedo magnitude follows this lag from the solar forcing to ocean temperature.
For direct solar forcing note Svensmark uses Forbush events to show impact from the Sun.
Effects of cosmic ray decreases on cloud microphysics J. Svensmark et al. 2012
Having lived in the tropics for a long time, within 100Ks of the equator. I can say the notion that convective cloud formation and precipitation is strongly tied to diurnal warming is wrong. It rains at all times of the day pretty evenly. The idea that tropical rainfall occurs in the afternoon results from places where sea breezes and orographic effects produce clouds and rain in the late afternoon.
Now to me, showing that clouds respond to the tropical surface temperatures, either on land or sea, is a no-brainer
I’ll suggest the response of tropical surface temperatures to clouds is rather more significant to climate change. We know there are effects on clouds: aerosols, GCRs that effect SSTs.
Willis, which paper are you referring to here?
Lindzen and Choi 2009 can be found here:
http://www.drroyspencer.com/Lindzen-and-Choi-GRL-2009.pdf
Lindzen and Choi 2011 which was a follow up addressing some of the criticisms is available here:
www-eaps.mit.edu/faculty/lindzen/236-Lindzen-Choi-2011.pdf
If it was another please specify.
Reviewer’s criticism of L&C:
Lastly, the authors go through convoluted arguments between forcing and feed backs. For the authors’ analyses to be valid, clouds should be responding to SST and not forcing SST changes. They do not bother to prove it or test the validity of this assumption. Again this is an assertion, without any testable justification.
The both are true seems to be patently obvious. Though someone ought to prove it formally, I have seen much less obvious stuff taken as given all though out climate research. Funny how they always get picky when they don’t “like” a paper’s findings.
Last thing I heard Dessler was trying to ridicule Spencer for suggesting cloud could be driving SST. Seems you can’t win.
Stephen Wilde: “In fact I think the apparent ‘lid’ on tropical SSTs that Willis has previously drawn to our attention is set at the point where the rate of evaporation rises to a level where convective uplift from the amount of water vapour present starts to exceed uplift from surface temperature alone.”
Good point, I had not made that connection and was a little sceptical of that claim when Willis made it. In fact I think the difference is that surface temperature only provides at negative feedback whereas uplift due to less dense water vapour is a self sustaining process. This makes it more than just a linear negative feedback. It’s like negative feedback with a tipping point!
That effect in itself would probable be sufficient to ensure climate stability on the upper end to a wide range of additional forcing.
I think Willis covered this in his posts on ARGO data. It was particularly clear in SH, there seemed to be an upper limit of about 38C of SST.
A forcing does indeed become a feedback, which becomes a forcing, which becomes a feedback. That’s what energy does. Perpetually stored energy in a highly variable intrinsic system is nearly impossible (and I say this because someone will tell me that such and such is a perpetually stored source of energy). So I would say that at some point, one can point to SST’s forcing cloud anomalies. But that is an arbitrary starting point ONLY. Cherry picked if you will. I can also say that clouds force SST anomalies. Both constructions are right and should be part of the background knowledge of basic science.
Kashua,
I think that what Willis is showing is that both factors are occurring:
Of course surface temperature responds to cloud. Given a constant input of solar heat (e.g. stop the Sun in the sky), a cloud comes over and the surface temperature drops. Again if the Sun’s input remains unchanged, and the cloud moves away, the surface temperature goes back up again. And, of course the amount of cloud depends on the amount of evaporation. The more evaporation (e,g. in the tropics), the greater the amount of cloud that develops. Finally, its a no brainer that evaporation increases with increasing sea-surface temperatures, supporting the opposite contention that the amount of cloud responds to (sea) surface temperature.
I think that what Willis is saying is that from the unchanging perspective of the Sun, there is a clear
mechanism that stabilizes world temperatures that involves clouds forming from increased evaporation which is responding to increasing sea and land surface temperatures.
John Marshall says:
June 7, 2012 at 3:32 am
Having lived and worked in the tropics I can say that convective clouds form over both ocean and land. Ocean formed convective cloud forms slower than land formed but still gives afternoon thunder storms, though not every day in the Maldives. Night time clouds did continue to form, and give rain, but this declined over night as the surface temperature cooled.
Having flown through the ITCZ several times I can confirm that it contains some very energetic convective clouds climbing to well over 70,000ft (21,336m). It would seem that the old claim that Cb clouds stopped building at the tropopause is wrong for the ITCZ.
Sounds like Gan.
It would seem that the old claim that Cb clouds stopped building at the tropopause is wrong for the ITCZ.
Not true. The tropopause is the top of the convective activity wherever the storms push it to. Its like a rolling sea and with discontinuities where the Hadley and Ferrel cells meet.
This is what Stephen Wilde is talking about as the Hadley Cell circulation increases in intensity the cells become larger and the jet streams get pushed away from the equator when the Hadley Cell circulation becomes weaker they shrink and the jet streams (and Ferrel Cells) move toward the equator. This is a larger scale longer term homeostatic response than the diurnal response that Willis has explained.
Clouds movement around equator is not random or only influenced by the sun. Clouds are electrically charged, so is the equatorial electrojet; intense tropical storms are partially result of interaction between these charged entities.
http://www.nasa.gov/centers/goddard/news/topstory/2006/space_weather_link.html
more at
http://www.vukcevic.talktalk.net/LFC20.htm
I think over-simplification of the events is not of assistance to understanding of complexity of the climate change.
One issue with the 20S to 20N latitude band is that that clouds, rainfall, and SSTs vary considerably by longitude and by the state of nearby regions. The Walker Circulation, for example means that clouds and rainfall move east or west in the Pacific depending on the state of the ENSO. The last series of La Ninas has even left some Pacific Islands with very little rainfall and clouds while Indonesia and Australia have been drenched. El Ninos result in the opposite situation.
Willis: I though “Hey, that’s a testable proposition to support or demolish my hypothesis”.
Clearly you’re not a Climate Scientist. In CliScientology, testable hypotheses are not allowed.
Snark aside, I do agree with you. Negative cloud feedback was the obvious flaw in the cAGW snake oil pitch from the beginning.
I would like to extrapolate Grey Lensman’s point about the impact of surface area in tropcial bush on evaporation to land areas. For the last 50 or 60 years, vast areas of improved grasses have been planted both in suburban and urban settings, In suburban settings the grass is for fodder for food animals while in urban settings the grass is for landscaping.
The grass leaves provides surface for condensation at night. When the sun comes up the temperature of the leaves rise to the the evaporation point. The liquid water then changes from potential energy to kinetic energry as it evaporates and rises into the atmosphere. When the last liquid water evaporates the temperature of the leaves start to rise heating the air around them.
The water vapor, containing the latent heat of evaporation, rises to a level where temperature and other conditions are favorable for condensation of water vapor back into liquid water (rain). As a part of condensation the kinetic energy is transformed back into potential energy thereby releasing the latent heat as specific heat causing the upper atmosphere to heat up.
These energy and phase changes cause time lag in the system, transfer heat from ground level to the upper atmosphere and supplies water vapor for cloud formation. This effect would be for land areas only.
JFD
I’m skeptical about double-blind reviewing. It isn’t really practical, at least in fields where there are relatively few people active. For example I can almost alway guess the names of the “anonymous” reviewers of my papers.
I’ve chosen the opposite alternative when reviewing other people’s papers. Many journals will let you chose whether you want to be anonymous or not, and I always select not to be, since I think that You should be willing to stand by your opinions openly. However, I realize that this is also difficult for many scientists who have to review papers by people who have e. g. influence over research funding.
Publishing reviews online together with the papers on the other hand seems a good idea with no obvious drawbacks. At least it would ensure that referees would have to produce reasonably rational and coherent reviews, which is not alway the case now.
****
Grey Lensman says:
June 7, 2012 at 4:46 am
The jungle retains vast amounts of moisture and due to its multilayer structure, has possibly far larger surface area than ocean to facilitate evaporation.
****
I’d agree — even the deciduous temperate forest here in the growing season is IIRC similar in evaporative potential as open water, as long as it isn’t abnormally dry.
Willis
Are you sure about the reviewing process for Climate Science? If true, that is one major reform that should have happened long ago.
I know in my field, physiology/neurology, that all of the journals I have submitted papers to or reviewed for are double blinded. This forces the reviewer to judge the paper on its merits rather than on any personal issues he or she has with the authors.
Double blind sounds good, but won’t work. The field is sufficiently small that the reviewer will know the authors and/or their fields of research and will be able check with them to verify. Even if that is a breech of rules the current state of pal review implies that a simple “Is this your paper?” “no, then whose is it?”, won’t stretch their ethics much.
Willis, you may want to fix an obvious typo in the third paragraph below your two-panel map:
“The same thing is true about southern Africa. In the southern summer (lower panel) the albedo is high in South America, with lots of clouds. In the southern hemisphere winter (upper panel), on the other hand, southern Africa loses its clouds, and above the Equator where it is summer we see increased albedo in the northern part of Africa.”
In the first sentence, where it says “the albedo is high in South America” it should be “in Southern Africa”.
[Thanks, Hector, fixed. -w.]
About double-blind reviewing: As an author I usually do not know the name of my reviewers, and as a reviewer I do not know the authors’ name. In other words, double-blind reviewing is already in place. The only way around would be for editors to cheat, i.e. telling reviewers the name of the author (for the sake of gatekeeping) or vice versa (never either situation happened to me, but then I do not publish or review papers on climate science for a climate science journal: not my field). The violation of double-blind reviewing would be, in the journals I know, a subversion of the normal procedure and a case of editorial malpractice.
I agree with Pamela Gray:
“So I would say that at some point, one can point to SST’s forcing cloud anomalies. But that is an arbitrary starting point ONLY. Cherry picked if you will. I can also say that clouds force SST anomalies. Both constructions are right and should be part of the background knowledge of basic science.”
In the lower latitudes, particularly during the summer, surface temperatures seem to be forcing clouds. At higher latitudes, it is actually cloudier when the surface temperature is colder (winter) than warmer (summer), which is opposite of the tropics. Albedo is lower in the winter at high latitudes because the sun angle is so much smaller and temperatures are colder, not because there are fewer clouds.
Right on the double blind approach is the best but most costly. Today it is less about quality and more about quantity and grant generation. Grants result from catering to the preconceived ideas and bias of the granter. The business of science has always been some measure of balance between the “old boy network” and analysis objectivity. Double blind or not I think publishing the reviews along with the paper will go a long way to shaping everyone up if not solving the problem.
I agree with Dennis Nikols P. Geo. and others Reviewing should be double blind but more important, the reviews should be published with the paper.
What’s bizarre about the reviewer comment is that, if it were true, that non-feedback cloud variations were confusing the signal, they would almost certainly skew the results in favor of positive feedback. And to some extent there probably are some non-feedback cloud variations that cause temperatures to change (Lindzen had lag correlation plots that hint this was going on in the short wave). But these create a positive feedback bias. Meaning that, if the reviewer’s suggestion were correct, Lindzen would have gotten too large a sensitivity.
I used atmospheric temps because the atmosphere itself will then determine the appropriate lag, not to mention the fact that clouds are not magically aware of the sea surface temperature below them, they respond to the temperature of their local environment (ie the atmosphere). I got strong negative feedback-even stronger if you variance adjust the tropospheric temps to match the surface. Me and another blogger tried to get an analysis like what I did published (that didn’t use quite the same method and got closer to no or weak positive feedback-probably biased to positive) the reviewers rejected it for what struck me as really stupid reasons. Some Bayesian bullsh*t (I am an unreconstructed frequentist) and some other objections that indicated they didn’t understand the paper.
So once again we have the sun and water driving the temperature. Seems legit.
I particularly like the composite in fig 2 as it really does portray our reality from a different perspective.
I’ve reviewed for conferences with very thorough double blind reviewing, and IMHO it doesn’t make any real difference, except it gives the appearance of not being biased towards established authors. I don’t think anything is lost by double blind reviewing, but I don’t think there is that much to be gained. As others have pointed out, anyone that stands out from the crowd will be immediately identifiable from the content of the paper whether their names are on it or not. But as nothing is lost, why not?
Publishing the reviews with the reviewers names will end up with either timid ineffective reviewing (as the reviewers will be rightly concerned that if they give an incorrect review it will reflect badly on them) or the review process taking even longer (because the reviewer will have to take even longer on the reviews making sure that they are accurate). “Third, in the fullness of time, we will have a record of who was right and who was wrong.” this is the very reason this proposal will not work, if someones academic reputation hangs onthe quality of the review, then they will want to put as much effort into the review as they do their own papers, which is simply unfeasable, they need to get their own work done as well.
It seems to me that the best way of guarding against pal review would be for the journal to publish a list of the reviewers they have used each year (possibly with the number of reviews performed). Some journals (e.g. Neural Networks) already do this as a way of thanking the academics that have supported the journal.
However at the end of the day, the reviewers are only human, so flawed papers will always slip through the net, no matter how much effort is expended.
Which reminds me, I have a couple of papers to review…
tty says:
June 7, 2012 at 7:44 am
Thanks, tty. The NSF has gotten the first results from their trial of double-blind reviews of grant proposals, but unfortunately I didn’t snag the link when I read it and can’t find it now … grrr, any assistance in locating it welcomed. In any case, one of their comments was that in a number of cases, reviewers who thought they know who wrote one of the proposals were entirely wrong.
So yes, they can guess, and in some cases they might be right … but if you have to sign your name to your review and it is published, it would at least make you cautious about favoring or opposing something based on your guess about the author …
w.
Willis Eschenbach – The issue referred to by the reviewer (assuming this was the L&C submission to PNAS) was that Lindzen and Choi required clouds to cause SST changes (as seen in cloud changes being related to SST, with cloud changes leading in their analysis), and the reviewer was objecting to that unsupported assumption.
Tied to this was the discussion in the earlier Trenberth 2010 paper (http://www.atmosp.physics.utoronto.ca/~jclub/journalclub_files/trenberth2010.pdf), and the following Dessler 2011 paper (http://geotest.tamu.edu/userfiles/216/Dessler2011.pdf), where Dessler notes:
“The observations show that larger negative slopes
exist when the cloud time series leads the surface temperature,
with mostly positive slopes when the temperatures leads the
cloud time series. Based on this correlation, LC11 conclude
that clouds must be initiating the climate variations.”
This also arises in the L&C11 AMIP model analysis, where they assume the same causality of clouds->SST, the same lead/lag relationship – even though those models, as written, have causality going in the opposite direction. In the models, that’s simply not what’s happening, and in the real world, L&C and Spencer appear to be the only ones holding this quite odd opinion you have criticized.
—
I believe you have misread those reviewer remarks. The issue is with L&C, not the reviewer.
Gotta say, the comments on double blind reviewing seem split between ‘It will never work’, and ‘In my field it’s the standard way it’s done’ … go figure. I don’t think both of those can be right, and one is theory while the other is practice.
w.
Willis, People always put their names in published book reviews, even highly technical books, so it must work.
KR says:
June 7, 2012 at 10:38 am (emphasis mine)
Thanks, KR, but that seems like a very tortured reading of a clear either-or statement by the reviewer. S/he said:
So near as I can tell, the reviewer is saying the exact opposite of what you claim …
w.
Anthony, the differences are that book reviews are not a check on the correctness of the book, just a rough guide to its overall worth. Book reviews don’t contribute much, if anything, to a scientists reputation.
REPLY: I was also thinking of technical books in science and industry, where facts do indeed have to be checked. For novels/fiction, yes your point is taken – Anthony
Willis Eschenbach – L&C11 have clouds forcing SST’s, the reviewer is pointing out that assumption, and stating that the paper and analysis is invalid as a result of the L&C assumption.
I have, incidentally, read L&C09, the L&C PNAS submission, L&C11, the reviews, and a number of the rebuttal papers. L&C sensitivity results are calculated with temperature changes lagged behind cloud changes.
From L&C11:
“Based on our simple model (viz Section 4b of Methodology), this ambiguity results mainly from nonfeedback internal radiative (cloud-induced) change that changes SST.” (emphasis added)
in other words, L&C11 consider clouds a forcing, not a feedback.
Anthony, book reviews of technical books are not checks of technical correctness either. That is performed by reviewers engaged by the publisher to check the correctness of the book before it is published (I have done this myself – the reward for which was a book ;o). The published book reviews at least in my field are essentially justified recommendations (or otherwise), but not a validation of the content.
Willis Eschenbach – “…a very tortured reading of a clear either-or statement by the reviewer…”
The reviewer stated that:
Requirement for validity: SST changes cause cloud changes.
Invalid analysis: Cloud changes cause SST changes.
L&C11: “Based on our simple model (viz Section 4b of Methodology), this ambiguity results mainly from nonfeedback internal radiative (cloud-induced) change that changes SST.” (emphasis added)”
I would agree that in isolation the reviewer’s comment might seem a bit ambiguous. In the context of the reviewed paper itself, however, I would consider it quite clear – the reviewer was pointing out that the L&C11 assumption, of nonfeedback cloud-induced changes forcing SST changes, was invalid. And based upon your initial post and the comments in this thread, you would seem to agree.
Willis said:
3. The clouds are making the sun move north and south of the Equator.
==========================================================
ROTFL —-so THAT’s how it works!
A paper reviewer said:
For the authors’ analyses to be valid, clouds should be responding to SST
and not forcing SST changes.
=============================================================
An amazing comment.
Said reviewer should be taken out to tour some commercial greenhouses.
They regulate internal temperature (and shade) by drawing canvas curtains
over the glass roof panels. It might interest the reviewer to note the outside
surface of the curtains are invariably white. These cloud analogues definitely
FORCE the internal temperature.
For that matter, all homes/buildings with curtains are able to repeat this to a
lesser degree to regulate both incoming and outgoing heat for maintenance
of an even (comfortable) internal temperature.
One has to wonder where these idiots are found ….
KR says: “in other words, L&C11 consider clouds a forcing, not a feedback.”
L&C11’s lag correlation graphs for shortwave forcing showed that the correlations of the shortwave flux changes with sea surface temperature changes were stronger with leads or lags, and changed sign depending on the lead or lag. They interpretated this to mean that the feedback signal, which should be at zero lag, was being corrupted by non feedback changes in shortwave flux which would cause temperature changes, ie “force” them.The reviewer said of this interpretation:
“For the authors’ analyses to be valid, clouds should be responding to SST and not forcing SST changes.”
It’s a bit difficult to follow, but as far as I can tell, what this means is that, in order for there intepretation to be correct and give them the correct result, clouds should be responding at LC11’s selected lag time. Read this way, the reviewer’s comment suggest an ignorance of the arrow of time. Positive lags of course correspond to feedbacks (although perhaps not the full feedbacks).
Now what you seem to be saying is rather different: in order for LC11’s lagged results to be correct, it must be true that the zero lag result contain some cloud changes that are not feedbacks. True. You also imply this is at odds with Willis. I don’t know about that. So I’ll ask the question:
Willis, is it you opinion that clouds changing on monthly timescales should exlusively be a function of the temperature of the sea surface roughly contemporary to it? If so, your understanding is not compatible with LC11’s lead lag analysis, which requires that some changes in clouds are not responses to the temperature. If so, the feedback should be found at zero lag (although I think there are physical reasons to expect some lag independent of the cause/effect issue).
Willis, where has your thermostat been for the last forty years? JP
I like your graphs. Have you made the data and code publicly available?
Double-blind reviewing of grant proposals poses a problem: a desideratum in awarding a grant to a team is whether the team has successfully carried out similar research in the past; over time, the better teams should get the greater funding amounts. Possibly not insurmountable; related, most successful teams cite a lot of their own work, so the reviewers know the team, or at least the PI almost surely.
I think that reviewers’ comments and authors’ responses might be made available as supporting online material, available to people who really want to know. Compared to the final product, the reviewer comments and intermediate drafts are usually not that interesting.
@ Willis
“PS: Since we’re discussing clouds as forcing and feedback, you’ll excuse me if I take this opportunity to re-post the following from my “Thermostat Hypothesis” paper. In it I am describing how the clouds and thunderstorms work as a governor to stabilize the temperature: …”
=====
I had not read that before. Excellent! Very well explained. Even a politician should be able to understand. Unless they are intentionally “double blind” in a common sort of way that would have an entirely different meaning than that which was discussed in the main post.
Andrew and Willis, without reading too much into what the reviewer said or meant, it’s pretty well established that,
– Clouds do not cause the bulk of temperature change that is caused during ENSO events (for example), though that’s an example of a dominant mode of tropical variability, and one that severely limits the usefulness of the method of choice that Lindzen has adopted for inferring “equilibrium climate sensitivity.” A number of independent authors have found this method to be unsuitable.
– There are entire books written on the subject of convection as well as tropical dynamics, and the factors giving rise to convection are considerably more complex than just knowing the surface temperature. Depending on where you go there may or may not be a strong diurnal cycle connected with heating of the ground by insolation. Some land areas feature midnight to early morning maxima of precipitation. There are also observed nocturnal maxima insconvection in regions over the ocean, where at least three our four mechanisms may be important (including destabilization caused by nighttime longwave radiative cooling) in addition to local effects such as complex terrain and sea-breeze circulations. The seasonal cycle has structure as well, associated with the movement of the ITCZ or monsoon onset/demise, again depending on location. Convection is modulated by synoptic variability (e.g, the MJO), changes in wind direction, hurricane activity, etc.
– It is not sufficient to consider only the shortwave component of cloud influence, since the greenhouse effect of clouds roughly cancels this influence. This is one reason there is no evidence for clouds operating to keep the tropics from overheating, or for providing a robust ‘thermostat mechanism.’ There are suggestions of this in the literature, but it has fallen out of favor.
@atarsinc Perhaps Willis termostat have a max and a min value they keep the temp within. Look at the earths temp over it’s life time tell me what you see, does it look like a stable system or not? Continents have moved, the sun has changed the atmosphere has changed and so forth, and during all this time temp has been within a narrow band.
Thanks Willis, for a logical explanation of mechanism that makes perfect sense to me.
As for unleavened clouds, perhaps that is what “the models” are using and are the root of their problems? 🙂
ursus augustus says, June 7, 2012 at 2:49 pm
Gives a whole new meaning to the Marvelous Breadfish :-).
“Kasuha says :
Apart of that, I kinda disagree that clouds respond to surface temperatures. ”
From what I have observed in sub tropical SE Queensland we have the following scenario :-
The land mass is heated during the day – and in Spring/Summer fairly rapidly.
The heated air begins to rise and a “sea breeze” begins.
This humid air is “sucked” into the now rapidly convecting air mass over the warmer land surface and in turn rises.
As this progresses throughout the day the afternoon clouds form.
If sufficient humid air is drawn in a storm forms and the result is a much cooler local environment that night.
I have seen this behaviour repeated over 50 odd years.
I kinda agree that clouds respond to surface temperatures.
C.Close:This is one reason there is no evidence for clouds operating to keep the tropics from overheating, or for providing a robust ‘thermostat mechanism.’
This is over the top. There is plenty of evidence for this. Willis’s Figure 2 in the thread root is only one such. There may indeed exist much counter evidence. The case for a themostat may be unproved and in balance might be weak. But to say there is no evidence tells me to discount other things you say and write.
Your point about looking beyond shortwave energy is well taken. However, the longwave energy that escapes is a function of a time-varying cloud cover. Remove the clouds and things cool off faster at night.
@Willis
“The same thing is true about southern Africa. In the southern summer (lower panel) the albedo is high in southern Africa, with lots of clouds. In the southern hemisphere winter (upper panel), on the other hand, southern Africa loses its clouds, and above the Equator where it is summer we see increased albedo in the northern part of Africa.
“…Again, this difference in effect shows that surface temperature is the driving factor, since the land temperatures change more with the seasons than do the ocean temperatures.”
+++++++++
Having spent 30 years studying the weather in Southern Africa I have to disagree with the main thrust of the argument. The winds change direction completely between summer and winter and that is the reason for the change in moisture in the atmosphere (excluding the Cape Town winter rainfall area which is on its own reversed cycle). When the clouds mostly disappear, early April in the summer rainfall area, it is still warm and can be warmer than January and February – December too in some years. Clearly temperature at the surface has little (if anything) to do with cloud formation.
Temperatures in ‘winter’ are as high as 25 C in the daytime but because of a lack of moisture, can drop below zero at night. What makes winters really cold is moisture. It if rains in winter (like this and the past couple of years) it is miserably cold. Winter rains are connected to the 19 year drought/wet cycle and it is at the peak ‘wet’ now. The more clouds, the wetter and colder it is. Surface temperatures are driven by cloud+rain. Obviously if it is cloudy it is colder but it takes rain/snow to get really cold. As many people find it surprising that it snows regularly in Africa, show them this:
http://www.wartrail.co.za/Motor(2106147).htm
Does the quarterback respond to the rushing linebacker or does the rushing linebacker respond to the quarterback. Anyone who knows anything about football would immediately say “both”.
Do clouds respond to changes in surface temperature or does surface temperature respond to changes in cloud cover. Anyone who knows anything about weather would immediately say…
Not sure what the argument is about.
Stephen,
If one were to take an undergraduate course in atmospheric science, it would be rather obvious why clouds often form when the surface is being heated by insolation. This is not a priori evidence of a “thermostat” nor does it have much bearing on the climate change issue.
Chris Colose: – Clouds do not cause the bulk of temperature change that is caused during ENSO events (for example),
How much of it do they cause?
There are entire books written on the subject of convection as well as tropical dynamics,
What are some recent ones that you recommend? I am expanding my library on climate science.
Chris Colose: This is not a priori evidence of a “thermostat” nor does it have much bearing on the climate change issue.
Personally I don’t like the teleology of the “thermostat hypothesis”, but the idea that negative feedbacks may be sufficiently strong to prevent heating above a physically realizable maximum is certainly worth considering. That there is no “a priori” evidence may be true, but when have scientists ever worried about “a priorI”? If the idea is testable, it should be investigated. It has considerable bearing on some of the climate change issue, in particular whether it is possible for the Earth to warm up as much as the AGW models predict (starting from where the earth is now), or for there to be a “runaway” effect.
Matthew R Marler says:
June 7, 2012 at 8:53 pm
Thanks, Matthew and Chris. Certainly we see this effect, of a maximum temperature regardless of input, in the Argo float data. This has been known for a while, I discussed it here.
However, it’s a mistake to think it is just simple negative feedback. Thunderstorms have the capability to cool the surface well below the temperature required for initiation. In a lagged system, this “overshoot” is a requirement for establishing the type of temperature maximum that is shown by my link above. It’s not just a passive linear or semi-linear feedback.
w.
Matthew,
Some standard atmospheric dynamics books include Holton’s Intro to Dynamic Meteorology (though with emphasis on mid-latitudes, an excellent supplement to this is Jonathan Martin’s Mid-latitude dynamics text…if only because he was a professor of mine back in an undergrad class). The texts by Adrian Gill as well as Valllis are excellent and thorough resources. I’m less acquainted with texts *specifically* on the tropics (my feeling is that someone still needs to write one, papers may be better for this from my experience, but I also sense that the general field is in more flux than those concerned with the dynamics of the mid-latitude cyclone for example). Kerry Emanuel has a general book on Atmospheric Convection, but I’ve only read small sections of it. A lot of standard texts on thermodynamics (Grant Petty’s being an excellent one) discuss some convection/instability stuff as well. (Note: all of these recommendations require calculus at least to the level of understanding vector relationships, partial derivatives, basic differential equations) and of course physics.
I fully agree that the prospective existence of “thermostats” is an interesting climate question for a number of reasons, both respect to clouds and other mechanisms. The class of cloud thermostats discussed by Willis has been extensively examined in the literature, dating at least back to Ramanathan in the early 90s, but is no longer widely accepted due to failure to account for sometimes very elementary factors.
There are thermostat mechanisms that operate outside of timescales of interest to us (e.g, silicate weathering), which has implications for a geologic view of climate change, but I can absolutely say that a “runaway greenhouse” is not possible for the current solar insolation received by Earth. It’s very hard for feedbacks on Earth to overcome the T**4 dependence of Stefan-Boltzmann. A runaway snowball is in the realm of physical possibility, and it’s quite possible for the ice-albedo feedback to overwhelm other stabilizing mechanisms (it evidently has in the past, as I discussed in the third post in the link on my name) but I don’t think that is a worry today.
But Willis, the observation of a “maximum SST” in the tropics, as well as a threshold for deep tropical convection, is simply a characteristic of the current tropical climate for reasons which I sense are reasonably understood by now – all based on fundamental stability criteria coupled to the large-scale circulation that the tropical atmosphere relaxes to.
The threshold for convection would change in a warming climate, and the SST distribution along with it. ARGO observations can’t sample a different climate. Ramanathan got this all wrong decades ago, and it would nice if he publicly disavowed his views.
Willis: It’s not just a passive linear or semi-linear feedback.
Simple? No.
Linear? No.
Self-organizing (as opposed to “controlled”)? Yes.
Chris Colose, thanks for the book recommendations. I’ll check them out from a library.
Rainfall over the tropical oceans peaks between 3 and 6 AM, ie before dawn. Clouds are at their maximum at this time.
http://journals.ametsoc.org/doi/abs/10.1175/1520-0493(1994)122%3C2296:AEOTDC%3E2.0.CO%3B2
What happens is the sun heats the ocean during the day and this heat is mostly retained in the oceans as air temperatures are above or close to the ocean surface temperature. After nightfall, the air temperature falls and the ocean surface now warmer than the air loses heat to the air mostly through evaporation. The warm moist air feeds convection (or feeds into existing convection processes) and results in precipitation causing clouds forming late in the night.
It appears to me that this diurnal cycle is the key to temperature regulation in the tropics, at least over the oceans.
Let’s say something (aerosols) causes more persistent clouds and an overall increase in cloudiness. This will reduce the amount of sunlight entering the oceans, but also reduce night time radiative cooling of the air above the ocean. The night time temperature differential between the ocean surface and the air will be reduced and less evaporation occurs. Resulting in fewer clouds and less precipitation (which means less heat transport upward in the atmosphere).
The climate acts to keep cloud cover stable over the 24 hour cycle.
Chris Colose says:
June 7, 2012 at 9:52 pm
Thanks, Chris. At present, there is a limit beyond which the ocean temperature doesn’t rise, no matter how much energy is coming in. The energy goes up, but the temperature doesn’t.
You claim that in a “warming climate” somehow this will all change. The only difference in a “warming climate” would presumably be greater forcing. But since greater forcing doesn’t warm the oceans beyond that limit today, what makes you think that greater forcing would push the ocean above that limit tomorrow? I mean it’s all very well to claim that, but upon what are you basing the claim?
Finally, I brought it up to show that indeed there are limits on how much large parts of the planet can warm, which obviously implies a phenomenon or phenomena which maintain that limit. I hold that the phenomena are a combination of clouds and thunderstorms, which cool the surface in a host of ways.
w.
PS—I fear that saying that the temperature limit is “based on fundamental stability criteria coupled to the large-scale circulation that the tropical atmosphere relaxes to” doesn’t say much at all … what “stability criteria”? What makes them “fundamental”? What are the non-fundamental stability criteria? What large-scale circulation does the tropical atmosphere “relax to”? Why would the relaxation of the tropical atmosphere result in a limit on the ocean temperature?
I fear that your meaning is not at all clear …
Chris Colose says:
June 7, 2012 at 9:43 pm
AFAICT, the main “elementary factors” leading to the lack of acceptance of the idea of thermostatic mechanisms are that they don’t lend themselves to alarmism, and that they disagree with the current paradigm that states that there is a linear relationship between forcing and temperature.
Seriously, Chris, what “elementary factors” do thermostatic mechanisms not account for? And where does Ramanathan discuss the fact that thunderstorms can cool the surface below the temperature required to initiate the thunderstorms?
I disagree that the analysis of thunderstorms as a governing mechanism has been “extensively examined in the literature”. It has scarcely been discussed in the literature at all. The thermostatic mechanism discussed by Ramanathan is quite different from the one I have proposed. In 1991, Ramanathan and Collins said that the albedos of deep convective clouds in the tropics limited the SST … but as far as I know, they didn’t discuss the idea of thunderstorms as a governing mechanism at all.
In other words, that all sounds like you are trying to hand-wave away my ideas because you have problems with them …
w.
A bit late on parade here. I’m a tropical operational forecaster. We look all the time for ‘hot’ spots in SST for MCS buildups. Its like clockwork. Anyone who doesn’t think there is a direct correlation with SST hot spots and cloud buildup is a bit naiive. Sometimes I feel like knocking a few heads and wouldn’t be surprised that the resonance resembles wood.
Willis said:
“indeed there are limits on how much large parts of the planet can warm, which obviously implies a phenomenon or phenomena which maintain that limit. I hold that the phenomena are a combination of clouds and thunderstorms, which cool the surface in a host of ways.”
Willis, you may not welcome this comment but in my humble opinion you really do need it for your hypothesis to work.
The relevant phenomenon which determines the limit on how much large parts of the planet can warm is atmospheric surface pressure.
As soon as there is enough water vapour for the convective uplift from that lighter than air water vapour to exceed the convective uplift from temperature at the surface alonethen nothing can raise the surface temperature above water any further.
P.Solar noted the significance above:
“P. Solar says:
June 7, 2012 at 6:09 am
Stephen Wilde: “In fact I think the apparent ‘lid’ on tropical SSTs that Willis has previously drawn to our attention is set at the point where the rate of evaporation rises to a level where convective uplift from the amount of water vapour present starts to exceed uplift from surface temperature alone.”
Good point, I had not made that connection and was a little sceptical of that claim when Willis made it. In fact I think the difference is that surface temperature only provides at negative feedback whereas uplift due to less dense water vapour is a self sustaining process. This makes it more than just a linear negative feedback. It’s like negative feedback with a tipping point!
That effect in itself would probable be sufficient to ensure climate stability on the upper end to a wide range of additional forcing.
I think Willis covered this in his posts on ARGO data. It was particularly clear in SH, there seemed to be an upper limit of about 38C of SST.”
Back to the post title: Forcing or Feedback?
Forcing takes place wherever you begin a sequence of events, with associated feedback showing up a few steps later.
Chicken or Egg?
Is the climate slowly forming the weather, or vice-versa?
What is the gender of angels?
By the way: what is THE climate?
”
Dave says:
June 7, 2012 at 4:50 am
Willis>
Is double-blind reviewing possible? I would have no trouble picking your writing from Anthony Watts’ or Steve McIntyre’s, let alone that of some of the alarmists, whether it has your name on it or not..
”
It very well may be quite difficult but I don’t think it is because of the reason you provide. Publishing scientific papers isn’t so much about the reading but in getting a publication. As such, creative writing and writing styles other than the stuffy formal one is not important. The author(s) regret boring the readers to death but if the reader is bored stiff, there’s less likelyhood of the reader finding fault with the paper and it makes it look even more ‘scientific’. Blogging successfully requires creative writing skills. One needs to attract and keep as many readers as possible by making things interesting, including having controversy.
I for one appreciate that Steve, Tony, Willis, and other regular contributors have styles rather than use the sterilized blah style of the classical scientific paper.
As for recognizing a double blind paper submission, that is mostly achievable by having a knowledge of who regularly publishes in the field and what they specialize in. Unfortunately, it may also be achieved in climate science by reading the abstract and conclusions and ascertaining the presence of advocacy. Some authors like hansen often push advocacy with conclusions that are not warranted based on the content of the paper. Others give lip service to CAGW just to avoid any potential conclusions that their paper might provide damage the CAGW hype. Some are mostly interested in disproving CAGW which may or may not show exactly who wrote it and which may or may not have legitimate conclusions based upon what may or may not be advocacy rather than solid science – but it doesn’t matter who wrote those to CAGW advocates screening papers because if it damages the hypothesis, the paper must be blocked. As for pal review, pals know what each other are working on anyway.
Hence, the well done blog becomes what the peer review process was supposed to be.
Peer review in publication was to weed out garbage and was to try to improve upon what was presented in an era where paper and ink were valuable commodities and room in publications was at a premium and prestige of the publication mattered. It was never part of the scientific method other than to assist in the repetition of experiments so has to help validate research efforts. Now, one often finds criticism from reviewers that it’s already been done once if one submits for publication a substantial duplication of an experiment already published.
“But for me, Figure 1 should convince even the most alarmist reviewer that clouds are responding to the surface temperature, both on land and over the ocean.”
There is a big problem with that, less clouds in winter is a positive feedback further away from the tropics, reduced winter cloud cover would increase coldness in the mid and upper latitudes in winter. All Fig 1 really shows is the seasonal movement of the ITCZ, which is dominated by the mid-higher latitude seasons rather than the equatorial seasons, as the midday Sun is directly overhead at the equinoxes at the equator and not at the solstices.
Fig 2 is interesting, apart from the asymmetry of more N.H. clouds in the tropics from 10.30am, while the tropics show increasing cloud through the day, beyond there the heavier cloud accumulates further towards the poles through the day.
>>
As soon as there is enough water vapour for the convective uplift from that lighter than air water vapour to exceed the convective uplift from temperature at the surface alone then nothing can raise the surface temperature above water any further.
>>
Easy with statements like “nothing can…” .
Perhaps we should not be too categorical about this. The temp swings are definitely not symmetrical and there is a strong neg feedback beyond around 30C , but this is not a hard ceiling. There is a quite a lot of temps getting as high as 35C in NH.
http://wattsupwiththat.files.wordpress.com/2012/02/all-n-hemisphere-floats-temps-gt-30-plus-gauss.jpg
“Easy with statements like “nothing can…” .”
Agreed. I spotted that after posting.
I think the point is that it becomes extremely difficult and requires a huge and rapid energy input to push sea surface temperatures above the observed ceiling.
This request may look OT to some readers.
Can anyone point to a plain-text webpage record of the data used to produce the TOP PANEL of figure 15 (annual oscillation of the inverted barometer (IB) effect in the NCEP system) on p.26 here [ http://ebooks.gfz-potsdam.de/pubman/item/escidoc:8469:2/component/escidoc:8468/9810.pdf ]?
If so, sincerest thanks.
Willis, I was thinking about this and began to wonder if this same concept could be used to explain the temperature changes related to the PDO cycles. For example, during the cool PDO cycle warm water remains in the tropics which leads to increased evaporation within the tropics and ultimately increased albedo which decreases the amount of sunlight that reaches the earth. During the warm PDO cycle warm water is dispersed northwards leading to a decrease in evaporation at the tropics and an increase in TSI forcing. A simple concept that should not be difficult to test using measurements of albedo during warm PDO years versus cool PDO years.
Willis,
Look, if you choose to believe in conspiracies, that is your prerogative but not one I’m going to play along with. I’m only responding because I think this is a fascinating subject, and one that has generated a large interest in the climate dynamics (and paleoclimate) community. There are actually people interested in this independent of whether it means AGW will be “catastrophic” or whether it has any bearing on how radiative forcing projects onto temperature. But I’m not convinced you’re adding anything new to the puzzle. Further, many of the conclusions you and other readers are coming to can be confirmed or rejected on grounds one could pick out of elementary textbooks on the subject.
It is nice that are you are trying to develop your personal theories, but reading the history of this subject might be a good start. If you are still convinced you have something new, then try to publish it in a journal. The fact is that there are many papers discussing tropical thermostats of various sorts, as well as the regulation mechanisms for the observed skewness in SSTs and the existence of warm pool regions. The distribution of solar insolation, ocean dynamics, the Hadley cell, the moisture and cloud distribution, etc are all part of the story in some way, but clouds do not exert a fundamental control on the absolute value of the SST. Some useful references are Wallace, 1992; Hartmann and Michelsen, 1993; Pierrehumbert, 1995; Sud et al., 1999; Clement et al., 2005; Sud et al., 2008; Williams et al., 2009. Evidence for change in the threshold of deep convection has come from Johnson and Xie, 2010 (Nat. Geo), consistent with theoretical expectations developed in some of those papers.
Of course, deep convection sets in when the lower air column becomes buoyant relative to the free troposphere (driven by the instability of the vertical profile of moist static energy). We also know that the onset of deep convection is possible outside the tropics at temperature well short of 28 C, indicating that the overlying deep convection in the tropics is linked to a persistent vertical thermodynamical structure of the tropical atmosphere. Because of the low rotation effect in the tropics, tropical dynamics are subject to a weak free atmosphere temperature gradient constraint, and meridional heating gradients are eefficiently smoothed out by the atmospheric circulation, and convection regions of deep convection are moreso driven by horizontal SST gradients. The free-troposphere temperature can increase in response to increasing CO2 or solar forcing so the SST threshold for deep convection will shift to warmer values as the free-troposphere temperature increases, and the deep convection helps promote the skewness in observed SST diagrams. It has nothing to do with a magical mechanism that can keep ocean temperature from ever exceeding some certain value.
“””””…..Ulric Lyons says:
June 8, 2012 at 5:49 am
“But for me, Figure 1 should convince even the most alarmist reviewer that clouds are responding to the surface temperature, both on land and over the ocean.”
There is a big problem with that, less clouds in winter is a positive feedback further away from the tropics, reduced winter cloud cover would increase coldness in the mid and upper latitudes in winter……”””””
Um ! Increased coldness, is commonly caused by an increased lack of sunshine. The tropics generally get more sunshine than the “upper latitudes” do (per squ metre of surface); in fact they do that a year round, not just in winter time. This means that the tropics are often warmer than the upper latitudes, which may explain all the ice in those upper latitudes.
It is generally observed, that “less clouds”, almost anytime, results in MORE sunlight; not Less sunlight, and more sunlight with less clouds, would result in less coldness. This would be directly contrary to your thesis, that less clouds (with more sunlight) leads to more coldness.
“””””…..Philip Bradley says:
June 7, 2012 at 5:39 am…………………..clouds and rain in the late afternoon. …..”””””
Would clouds and rain in the LATE afternoon, be a weather event, rather than a climate change event, such as; for example, clouds and rain in the afternoon ?
“””””…..Philip Bradley says:
June 8, 2012 at 12:06 am
Rainfall over the tropical oceans peaks between 3 and 6 AM, ie before dawn. Clouds are at their maximum at this time.
http://journals.ametsoc.org/doi/abs/10.1175/1520-0493(1994)122%3C2296:AEOTDC%3E2.0.CO%3B2
What happens is the sun heats the ocean during the day and this heat is mostly retained in the oceans as air temperatures are above or close to the ocean surface temperature. After nightfall, the air temperature falls and the ocean surface now warmer than the air loses heat to the air mostly through evaporation. The warm moist air feeds convection (or feeds into existing convection processes) and results in precipitation causing clouds forming late in the night…….”””””
You are NOT suggesting that a warm moist day leads to a warm moist night and forms clouds, as the night air cools; are you ?
All climate 101 texts teach, and all meteorologists announce that it is the clouds at night that cause it to be warm at night. Are you suggesting that this information is false ?
KR says:
June 7, 2012 at 11:25 am
in other words, L&C11 consider clouds a forcing, not a feedback.
A feedback is a delayed forcing. This is all semantics.
The feedback which Willis describes is surely an inevitable outworking of Hadley cell convection. Hadley cell convection redistributes heat from the equator to higher latitudes. If there is increased heat in the system, then the Hadley cell circulation will become more energetic as a consequence, meaning more air uplift in the tropical ITCZ, and more cloud. This is self-evident, where is the problem here?
Chris Colose says:
June 8, 2012 at 4:11 pm
Chris, you are the only person to mention conspiracies in this thread. I have said nothing about them in the slightest, and I generally don’t. So I haven’t a clue what you are on about, but it ain’t me, babe, no, no, no …
If you have an objection to something I’ve said, QUOTE MY WORDS so that we can at least guess what you are talking about.
w.
On being able to tell who the person writing something is by their style or whatever, without their name attached, I am reminded of the story of Johann Bernoulli’s Brachistochrone Curve Problem, to which a solution (one of five submissions from various big names in mathematics of the time) was anonymously offered by Issac Newton. Johann Bernoulli recognized the work of the master, though:
“tanquam ex ungue leonem”
I know the lion by his claw.
“If there is increased heat in the system, then the Hadley cell circulation will become more energetic as a consequence, meaning more air uplift in the tropical ITCZ, and more cloud. This is self-evident, where is the problem here?”
The problem is that global cloudiness decreases when the Hadley cell becomes more energetic despite the increased intensity of the ITCZ.
Hence my more complex scenario which seeks to provide a global solution and include a solar driven element.
George E. Smith says:
June 9, 2012 at 2:59 pm
“””””…..Ulric Lyons says:
June 8, 2012 at 5:49 am
“But for me, Figure 1 should convince even the most alarmist reviewer that clouds are responding to the surface temperature, both on land and over the ocean.”
There is a big problem with that, less clouds in winter is a positive feedback further away from the tropics, reduced winter cloud cover would increase coldness in the mid and upper latitudes in winter……”””””
Um ! Increased coldness, is commonly caused by an increased lack of sunshine. The tropics generally get more sunshine than the “upper latitudes” do (per squ metre of surface); in fact they do that a year round, not just in winter time. This means that the tropics are often warmer than the upper latitudes, which may explain all the ice in those upper latitudes.
It is generally observed, that “less clouds”, almost anytime, results in MORE sunlight; not Less sunlight, and more sunlight with less clouds, would result in less coldness. This would be directly contrary to your thesis, that less clouds (with more sunlight) leads to more coldness.
___________________________________________
I disagree.
I think it would be safer to say that the less water vapor (including clouds) the more violent the swings between day and night temperatures. Deserts are notorious for their violent swings in temperature. Water vapor has a modifying effect on the temperature decreasing day time temps and raising night time temps.
Cloud/precipitation also seems to be relegated to a band of temperature. If it is too cold it doesn’t snow. If it starts getting over 90F (32 C) you are going to see those afternoon thunderstorms build and cool things off if there is any sources of water vapor near.
@george E. Smith says:
June 9, 2012 at 2:59 pm
“This would be directly contrary to your thesis, that less clouds (with more sunlight) leads to more coldness.”
Well I did specify “in winter”, and at higher latitudes more cloud cover in winter can raise daytime temp’s and considerably raise night-time temp’s. My point though was hypothetical and is actually contrary to observation, as Jim Clark picked up on:
http://wattsupwiththat.com/2012/06/07/forcing-or-feedback/#comment-1003814