Guest Post by Willis Eschenbach
It has been known for some time that the “Pacific Warm Pool”, the area just northeast of Australia, has a maximum temperature. It never gets much warmer than around 30 – 31°C. This has been borne out by the Argo floats. I discussed this in passing in “Jason and the Argo Notes“, and “Argo Notes Part 2“. I’d like to expand on this a bit. Let me be clear that I am by no means the originator of the claim that there is a thermostat regulating the maximum ocean temperature. See among many others the Central Equatorial Pacific Experiment. I am merely looking at the Argo data with this thermostat in mind.
First, Figure 1 shows the distribution of all of the ~ 700,000 surface temperature measurements taken by Argo floats to date.
Figure 1. A “histogram” shows how many data points fall in each of the 1°C intervals shown along the bottom axis. The maximum is in the interval 28°-29°C.
The number of temperature records peaks around 29°C, and drops quickly for temperatures above 30°C. This clearly establishes the existence of the mechanism limiting the oceanic temperatures.
What else can the Argo data tell us about this phenomenon? Quite a bit, as it turns out.
First, a look at the year by year evolution of the limit, and how it affects the temperatures at different latitudes.
Figure 2. Annual temperature variations measured by all northern hemisphere argo floats that exceeded 30°C. Temperature observations are colored by latitude. Click on image for full-sized graphic.
A couple points of interest. First, the cap clearly affects only the warm parts of the year. Close to the equator, that is most of the year. The further from the equator, the less of the annual cycle is affected.
Second, the majority of the breakthroughs through the ~30° ceiling that do occur are from areas further from the equator, and are short-lived. By and large, nobody exceeds the speed limit, especially those along the equator.
Figure 3 is a closeup of the years since 2005. I chose this starting point because prior to that the numbers are still changing due to limited coverage. To show how the mechanism is cropping the tops of the warmer parts of the year, I have added a Gaussian average (129 point width) in dark gray for each two-degree latitudinal band from 0°-2°N up to 10°-12°N.
Figure 3. Annual temperature variations measured by all northern hemisphere argo floats that exceeded 30°C. Dark lines have been added to highlight the average annual swings of the data by latitude band. Click on image for full-sized graphic.
As you can see, the warm parts of the yearly cycle have their high points cropped off flat, with the amount cropped increasing with increasing average temperatures.
Finally, here is the corresponding plot for the southern hemisphere:
Figure 4. Annual temperature variations measured by all southern hemisphere argo floats that exceeded 30°C. Click on image for full-sized graphic.
Note that there is less of the southern ocean that reaches 30°C, and it is restricted to areas closer to the equator.
Next, where are these areas that are affected by the temperature cap? I had always thought from the descriptions I’d read that the limitation on ocean temperature was only visible in the “Pacific Warm Pool” to the northeast of Australia. Figure 5 shows the areas which have at some point been over 30°C.
Figure 5. Locations in the ocean which are recorded at some time as having reached or exceeded 30°C.
Figure 5a. A commenter requested a Pacific-centered view of the data. We are nothing if not a full-service website.
Clearly this mechanism operates in a wider variety of oceans and seas than I had realized, not just in the Pacific Warm Pool.
Finally, here is another way to consider the effect of the temperature maximum. Here are the average annual temperature changes by latitude band. I have chosen to look at the northern hemisphere area from 160 to 180 East and from the Equator to 45°N (upper right of Figure 5, outlined in cyan), as it has areas that do and do not reach the ~ 30° maximum.
Figure 6. Average annual temperature swings by latitude band. Two years (the average year , shown twice) are shown for clarity.
Note that at say 40°N, we see the kind of peaked summer high temperatures that we would expect from a T^4 radiation loss plus a T^2 or more evaporative loss. It’s hard to get something warm, and when the heat is turned down it cools off fast. This is why the summer high temperature comes to a point, while the winter low is rounded.
But as the temperature starts to rise towards the ocean maximum, you can see how that sharp peak visible at 40°N starts first to round over, then to flatten out at the top. Curiously, the effect is visible even when the temperatures are well below the maximum ocean temperature.
Speculations on the mechanism
I want to highlight something very important that is often overlooked in discussions of this thermostatic mechanism. It is regulated by temperature, and not by forcing. It is insensitive to excess incoming radiation, whether from CO2 or from the sun. During the part of the year when the incoming radiation would be enough to increase the temperature over ~ 30°, the temperature simply stops rising at 30°. It is no longer a function of the forcing.
This is very important because of the oft-repeated AGW claim that surface temperature is a linear function of forcing, and that when forcing increases (say from CO2) the temperature also has to increase. The ocean proves that this is not true. There is a hard limit on ocean temperature that just doesn’t get exceeded no matter how much the sun shines.
As to the mechanism, to me that is a simple question of the crossing lines. As temperature rises, clouds and thunderstorms increase. This cuts down the incoming energy, as well as cooling the surface in a variety of ways. Next, this same process moves an increasing amount of excess energy polewards. In addition, as temperature rises, parasitic losses (latent and sensible energy transfers from the surface to the atmosphere) also go up.
So … as the amount of total radiation (solar + greenhouse) that is warming any location rises, more and more of the incoming solar radiation is reflected, there are more and more parasitic losses, more cold water and air move from aloft to the surface as cold wind and rain, and a greater and greater percentage of the incoming energy is simply exported out of the area. At some point, those curves have to cross. At some point, losses have to match gains.
When they do cross, all extra incoming energy above that point is simply transferred to the upper atmosphere and thence to the poles. About 30°C is where the curves cross, it is as hot as this particular natural system can get, given the physics of wind, water, and wave.
I make no overarching claims for this mechanism. It is just one more part of the many interlocking threshold-based thermostatic mechanisms that operate at all temporal and spatial scales, from minutes to millennia and kilometres to planet-wide. The mechanisms include things like the decadal oscillations (PDO, AMO, etc), the several-year Nino/Nina swings, the seasonally opposing effects of clouds (warming the winters and cooling the summers), and the hourly changes in clouds and thunderstorms.
All of these work together to maintain the earth within a fairly narrow temperature band, with a temperature drift on the order of ± 0.2% per century. It is the stability of the earth’s climate system which is impressive, not the slight rise over the last century. Until we understand the reasons for the amazing planetary temperature stability, we have no hope of understanding the slight variations in that stability.
My regards to you all,
w.
UPDATE (by Anthony):
Dr. Roger Pielke Sr. has some praise for this essay here:
Richard M says:
February 13, 2012 at 6:10 am
Say what? Provide a quote where I’m taking the “opposite position” with N&Z. And what is the “opposite position” to the position I took above? It wasn’t N&Z playing with the data that was the problem, It was their drawing of false theoretical conclusions that I took issue with. I would have been happy to see them play with the data. Instead, they tortured it out of recognition.
Say what? What “interesting observations” did I have no interest in pursuing? N&Z didn’t make a single one nor did anyone else point out any, as far as I knew. This is all a mealy-mouthed, unsubstantiated unpleasant personal attack.
And I think you have your head up your fundamental orifice. You have given us nothing but a slimy character assassination, without a single quotation or citation or fact to back it up. Not one. That’s the action of a cowardly low-down sneak.
Richard M., you are shaming yourself with these kinds of nasty unsupported allegations. Stick to the science.
w.
John Brookes says:
February 13, 2012 at 6:34 am
I fear you are not paying attention to what they are actually saying. The CAGW crowd keep saying that the world’s poor, who by and large live in the tropics, will be hit the hardest by global warming.
w.
Jeff Alberts says:
February 13, 2012 at 7:37 am
Man, you “ad-hominem” guys never take a break, do you? I don’t care if it was found written on a bathroom wall. If it’s true, then it’s true, and thus it is worth paying attention to, whether Holmes is fictional or not.
Unless, of course, you are arguing that one should indeed theorize without facts … and in that case, even Sherlock Holmes couldn’t help you.
w.
What about the science then, what has been written about ocean temperature and its physics during the last 100 years? Surely there must be tons of stuff! I hardly see any reference to any papers in these discussions. Is the wheel being invented anew here? I am not a climatologist or something like that, but I do not see any problems whatsoever with temperatures reaching a roof, that´s plain physics. Global warming is not about oceans reaching 36 C or deserts 57.9 C. The issue is the long term storage of energy in marine systems. Nevertheless, it is very interesting to see some tinkering with that amount of data.
Willis Eschenbach said @ur momisugly February 13, 2012 at 8:35 am
Forgive them Lord, they know not what they do 😉
From: http://www.thecatalyst.org/physics/chapter-two.html
Stephen Wilde says:
February 13, 2012 at 8:24 am
Now you are complaining you are being censored? Hang on … OK, I just checked. Your claim that you are being censored is a LIE. You are LYING about being censored, Stephen, your nattering nonsense is still right there on this very page to mislead the innocent reader.
I suppose I shouldn’t be surprised that a lying pressure-head agrees with Richard M. that I’m being a mean man by not paying attention to N&Z’s oh-so-brilliant fantasies … just go away, Stephen, your lies are not wanted here.
w.
PS—I love your asinine certainty, your unshakeable conviction that the “top limit on sea surface temperature cannot realistically have any cause other than global atmospheric pressure” … Richard M, I hope you see the kind of adherents your views draw …
“This is all despite the fact that I have clearly shown, in “A matter of some gravity” that if there are no GHGs and the atmosphere is transparent, then no pressure or gravity mechanism, or any other method, can raise the surface above the S-B blackbody temperature.”
You did not show that at all. You designed an impossible scenario to screen out all the variables that would apply in a non GHG world and which would have produced a lapse rate as per the Gas Laws.
Apart from that you keep misrepresenting the views of those who argue that the Gas Laws are relevant and fail to acknowledge the nuances of opinion between such persons.
I for one do not deny the thermal characteristics of GHGs but aver that they are neutralised by other non radiative processes including the very convection based thermostat that you and many others propose.
Indeed such a thermostatic process based on convection is integral to a pressure based mechanism. If pressure is not relevant then convection cannot happen. It occurs because a parcel of air through heating and expansion becomes light enough to overcome the weight of the atmosphere above it. That is basic physics.
Water vapour being lighter than air overcomes the downward pressure more readily.
“Now you are complaining you are being censored? Hang on … OK, I just checked. Your claim that you are being censored is a LIE. You are LYING about being censored, Stephen”
It appears that I drew an incorrect conclusion from your use of the ‘snip’ term in the portion you quoted.
So, not a lie, simply a misapprehension. You really must try to avoid paranoia old chap 🙂
@Willis Eschenbach says:
February 13, 2012 at 8:26 am
Along that coast runs the Humboldt´s cold current, which comes from Antarctica.UN´s FAO has a paper that perhaps you know it:
ftp://ftp.fao.org/docrep/fao/005/y2787e/
(See in #8 pdf the graph at page 50th)
richard verney says:
February 13, 2012 at 8:30 am
This particular line of nonsense is discussed at length in “Radiating the Ocean“. Short answer? Downwelling long-wave infrared (DWLWIR) can indeed heat the ocean. The proof is in the fact that the ocean receives about 170 W/m2 from the sun, radiates away energy at about 390 W/m2, and loses about 100 W/m2 via evaporation and conduction/convection.
If the ocean cannot be warmed by downwelling infrared, and it’s gaining 170 W/m2 from the sun and losing about 490 W/m2 through radiation and parasitic losses … then where is the other 320 W/m2 coming from to keep the ocean from freezing?
Richard, neither you nor anyone else has ever answered that question. As I result, I continue to hold that yes, LWIR is known to heat rocks, trees, kids, houses, and the land in general, and there is no reason that it cannot heat water as well.
Yes, it is absorbed in the first 10 microns of the water … but the same is true about where it is absorbed in rocks, trees, kids, houses, and the land in general. Nobody thinks that LWIR can’t heat kids because it is absorbed in the first 10 microns of their skin.
The main question for you “can’t be absorbed” folks to answer, and the one you simply can’t answer is this: if DWLWIR is not absorbed by the ocean … where is the other 390 W/m2 coming from to keep the ocean from freezing?
w.
John Brookes says:
February 13, 2012 at 6:34 am
So the equator won’t heat up much, but the energy will be carried to cooler climes, which will become warmer. Sounds reasonable. Pretty much what the CAGW crowd say.
No they don’t. They say that CO2 = CAGW should have occurred at both Poles first, that a Tropical Troposhperic Hot Spot should have developed, that measurable Ocean Heat Content should have increased, that the rate of Sea Level Rise should not have decreased, that Accumulated Cyclone Energy and Category 4-5 Hurricanes should not have decreased, that Himalayan glaciers should have shown a net decrease in extent, that stripbark pine tree ring indices should not have decreased, that Atmospheric Water Content and Optical Density should have increased, that by now we should have had 10’s of millions of Climate Refugees, that Malaria should have spread, that Wind and Solar energy should have worked to replace conventional energy sources, that their alleged cure is not much worse than their alleged disease…etc….and that the last 10+ years of Global Mean Temperature should not have flattened.
But not to worry, John, your legacy as having supported the Greatest Pseudo-Scientific Hoax Evah! is still firmly intact!
Bill Illis says:
February 13, 2012 at 4:13 am “…Now let’s take this insight and go back to Pangea at 265 Mya….”
It appears that this hot time handled itself by pushing lots of heat to the poles. Scotese’s paper: Gondwanan Paleogeography and Paleoclimatology, 1998, indicates that the area comprising Antarctica and Australia, while at high latitudes (above 60˚S) were warm, temperate regions, exhibiting coal and kaolinite deposits. According to the text, there are no indicators of glaciation from mid-Permian to mid-Jurassic (ca. 270-175 MYBP) although there’s a lot of landmass at or near the South Pole, at least at the start of the period.
Looking at 255.jpg, I would tend to think of the China complex acting like Indonesia today, with lots of hot water piled up around it on occasion, and Paleo-Tethys Sea behaving like the Indian Ocean today. Physically, they lay out remarkably the same. The question is: were those seas hotter than 30˚C? I doubt it; the processes that moderate SSTs today worked then, and they worked a lot harder. Scotese refers to a “mega-monsoonal” phenomenon (Parrish, 1993) working there. (I haven’t read that paper or looked into the concept). There is also a suggestion that the Earth’s atmosphere was denser then than now, and I think that could work to increase atmospheric T (and so SST?).
Just to get back to the observations analysis. Has anyone calculated the total volume, of the surface tension layer, of the oceans surface? How much “seawater” are we talking about (1st couple of microns)? GK
“where is the other 320 W/m2 coming from to keep the ocean from freezing?”
Assuming that figure to be correct then obviously it is coming from a dynamic energy exchange with the atmosphere.
Anyway, what does Willis’s position on all this boil down to ?
Apparently Willis contends that the Gas Laws do not apply to an atmosphere that contains no GHGs.
Good luck with that, as they say. I’d be interested to see some evidence.
“Nobody thinks that LWIR can’t heat kids because it is absorbed in the first 10 microns of their skin.”
It can’t heat kids whose skin is kept constantly wet.
Nisse said @ur momisugly February 13, 2012 at 9:00 am
Willis referred to Ramanathan and Collins 1991 & De-Zheng Sun & Zhengyu Liu 2000 early in this thread. Yes there are hundreds of papers that note the relative stability of Earth’s equatorial region and somewhat fewer that propose mechanisms for this. I’m sure that the references in the two papers Willis referred to and a Google Scholar search on those papers will provide many hours of interesting reading 🙂
Willis rants on and on and then ends with this beauty:
And I think you have your head up your fundamental orifice. You have given us nothing but a slimy character assassination, without a single quotation or citation or fact to back it up. Not one. That’s the action of a cowardly low-down sneak.
Richard M., you are shaming yourself with these kinds of nasty unsupported allegations. Stick to the science.
Willis, no quotations were needed as all I did was point out the obvious. You weren’t at all interested in N&Z’s observations but now you defend observations without mechanism. It’s also pretty obvious from your ad hom filled response that you also realize at some level what I said is true. I would suggest you step back and look at what I stated logically.
BTW, I’m not “shaming myself” and others are not “embarrassing themselves” by stating their opinions. One wonders why you can’t argue your points without all the emotion.
Stephen Wilde says:
February 13, 2012 at 9:07 am
Stephen, if you are so stupid that when you see the word “snip” in a reply to you that you jump to the conclusion that you are being censored, I fear you are beyond my poor power to help.
As to paranoia, you’ll have to help me there. I get the distinct feeling I’m being followed from thread to thread by clueless pressure-heads who want to use the prestige of WUWT in order to lend a false luster of believability to their ludicrous ideas.
Am I being paranoid?
w.
Richard M says:
February 13, 2012 at 9:53 am
No quotations or evidence needed when you attack a man?
Richard, it’s surprising. Previously, you hadn’t struck me as the kind of sleazy skank who would attack a man’s character, and then when asked for evidence to back up his nasty allegations, would say that no evidence was needed. Don’t know why, but I had a different impression, you seemed like kind of a decent honest guy.
I guess we can all get fooled. I know I was.
w.
Stephen Wilde says:
February 13, 2012 at 9:49 am
Cite? As I have said many times, if you disagree with me, QUOTE MY WORDS. I have never said that in my life, Stephen, so in my opinion you are LYING AGAIN.
Although I’m sure you’ll come back to say it was just an innocent error, you truly thought I had said something of that kind but now you just can’t find the reference blah blah blah …
I call that kind of action “lying by omission”. You make up something you think I said, and then you omit the crucial step of finding out if I actually said it. That is a deliberate action, and that is what makes your actions a lie rather than the innocent mistake I’m sure you’ll try to blame it on.
w.
you know willis. there might have been some speck of wisdom in my suggestion ( christmas 2010)
that WUWT should avoid posting junk science. Like N&Z. On one hand, of course, there is the notion that bad science will die on the battlefield of ideas. That debate will clear away ignorance.
On the other hand stupidity is contagious, like a virus. It’s a really fine line. But I fear that WUWT is ending up looking like a higher traffic version of the talkshop. There is a big difference between marginal science, that might be correct ( say Christy) and the lunatic fringe that can’t be right. The folks who cannot be right, can never admit that they are wrong.
Well if you do accept that the Gas Laws apply to a non GHG atmosphere then you would have no problem with the concept of a higher temperature at the surface and a pressure induced lapse rate would you ?
Willis Eschenbach said @ur momisugly February 13, 2012 at 10:06 am
Geez guys, whatever happened to the Principle of Charity? You’ve turned a spark, into an ember and then a full on bonfire. You make me feel homesick… my father and I were like that when I was a teenager living at home.
Looking at the graphs and aware of the earlier discussion by Willis of the day-night change in water temperature and the formation of thunderstorms in the tropics, it seems to me that the width of the line of the maximum temperature is the diurnal variation in the water temperature at the limit. The ARGO buoys reach the surface at all times of day, send their signals to the satellite and begin their cycle again. Thus the data for the readings must show the surface temperature range of the day-night temperature variation. This range is the evidence of the thermostatic action of the cloud forming processes in the equatorial waters.
Stephen Wilde says:
February 13, 2012 at 9:05 am
I’m sorry, Stephen. I’ll try to do a better job of acknowledging the nuances of the differing beliefs of the gravity-heads versus the pressure-heads. It’s just difficult keeping them straight. The problem is that it is hard to distinguish between the various kinds and styles of handwaving. I’m not real good at that. For example, in the same email you say:
And that’s where the email ends …
OK, now we’re getting somewhere. I now know that one of your nuances is that you think water vapor overcomes downward pressure more readily than air. I’ll keep that in mind next time I’m considering how well different things “overcome downward pressure”. I suspect, for example, that rocks have a hard time overcoming downward pressure.
w.