Guest Post by Willis Eschenbach
Once again, the crazy idea that downwelling longwave radiation (DLR, also called infra-red or IR, or “greenhouse radiation”) can’t heat the ocean has raised its ugly head on one of my threads.
Figure 1. The question in question.
There are lots of good arguments against the AGW consensus, but this one is just silly. Here are four entirely separate and distinct lines of reasoning showing that DLR does in fact heat the oceans.
Argument 1. People claim that because the DLR is absorbed in the first mm of water, it can’t heat the mass of the ocean. But the same is true of the land. DLR is absorbed in the first mm of rock or soil. Yet the same people who claim that DLR can’t heat the ocean (because it’s absorbed in the first mm) still believe that DLR can heat the land (despite the fact that it’s absorbed in the first mm).
And this is in spite of the fact that the ocean can circulate the heat downwards through turbulence, while there is no such circulation in the land … but still people claim the ocean can’t heat from DLR but the land can. Logical contradiction, no cookies.
Argument 2. If the DLR isn’t heating the water, where is it going? It can’t be heating the air, because the atmosphere has far too little thermal mass. If DLR were heating the air we’d all be on fire.
Nor can it be going to evaporation as many claim, because the numbers are way too large. Evaporation is known to be on the order of 70 w/m2, while average downwelling longwave radiation is more than four times that amount … and some of the evaporation is surely coming from the heating from the visible light.
So if the DLR is not heating the ocean, and we know that a maximum of less than a quarter of the energy of the DLR might be going into evaporation, and the DLR is not heating the air … then where is it going?
Rumor has it that energy can’t be created or destroyed, so where is the energy from the DLR going after it is absorbed by the ocean, and what is it heating?
Argument 3. The claim is often made that warming the top millimetre can’t affect the heat of the bulk ocean. But in addition to the wind-driven turbulence of the topmost layer mixing the DLR energy downwards into lower layers, heating the surface affects the entire upper bulk temperature of the ocean every night when the ocean is overturning. At night the top layer of the ocean naturally overturns, driven by the temperature differences between surface and deeper waters (see the diagrams here). DLR heating of the top mm of the ocean reduces those differences and thus delays the onset of that oceanic overturning by slowing the night-time cooling of the topmost layer, and it also slows the speed of the overturning once it is established. This reduces the heat flow from the body of the upper ocean, and leaves the entire mass warmer than it would have been had the DLR not slowed the overturning.
Argument 4. Without the heating from the DLR, there’s not enough heating to explain the current liquid state of the ocean. The DLR is about two-thirds of the total downwelling radiation (solar plus DLR). Given the known heat losses of the ocean, it would be an ice-cube if it weren’t being warmed by the DLR. We know the radiative losses of the ocean, which depend only on its temperature, and are about 390 w/m2. In addition there are losses of sensible heat (~ 30 w/m2) and evaporative losses (~ 70 w/m2). That’s a total loss of 390 + 30 + 70 = 490 w/m2.
But the average solar input to the surface is only about 170 watts/square metre.
So if the DLR isn’t heating the ocean, with heat gains of only the solar 170 w/m2 and losses of 390 w/m2 … then why isn’t the ocean an ice-cube?
Note that each of these arguments against the idea that DLR can’t warm the ocean stands on its own. None of them depends on any of the others to be valid. So if you still think DLR can’t warm the ocean, you have to refute not one, but all four of those arguments.
Look, folks, there’s lot’s of good, valid scientific objections against the AGW claims, but the idea that DLR can’t heat the ocean is nonsense. Go buy an infrared lamp, put it over a pan of water, and see what happens. It only hurts the general skeptical arguments when people believe and espouse impossible things …
w.
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Smokey says:
August 15, 2011 at 7:37 pm
“Dave Springer,
Since the ocean doesn’t glow in the infrared,”
The ocean certainly does glow in the infrared. All matter with a temperature above absolute zero glows in some portion of the spectrum. Discounting glow from rarified ionized gases the glow is pretty much a continuous blackbody spectrum with a center frequency set by its temperature. The difference between land and ocean is that it glows a lot less than land does because most of the energy leaving travels as latent heat of vaporization. The dearth of infrared energy leaving the ocean is made up for by an increase of infrared energy coming out of the cloud deck where that latent heat is being transported to and released.
Keith Minto says:
August 15, 2011 at 7:01 pm
“If the air at the ocean surface is humid that means it has already condensed and released its heat;”
Wrong. You can see it if it condenses. If it condenses near the surface we call it fog. If it condenses farther up we call it clouds. In either case you can see it after it condenses. If you can’t see it then it hasn’t condensed.
“believe that DLR can heat the land”
If DLR doesn’t heat the land, the borehole temperature measurements don’t make sense. If heat can penetrate ground without convection, it can penetrate water.
richard verney says:
August 15, 2011 at 7:12 pm
I think it’s more like when I told my wife that I earned an extra $20,000 by purchasing a new Corvette instead of a used Ferrari.
The government pulls that one on the taxpayers all the time. They “reduce spending” by increasing it less than they planned. I don’t know who that’s supposed to fool but it won’t work on me and it certainly didn’t fool my wife when I tried it on her.
Smokey says: “Since the ocean doesn’t glow in the infrared, …”
What would lead you to this bizarre conclusion???
For $39 you can buy this “infrared glow meter” from LL Bean to observe water http://www.llbean.com/llb/shop/50247?pi=865287&subrnd=0&qs=3021021_pmd_nextag
If you have a little more money, you can buy a weather satellite and use the “infrared glow meter” to determine global SST. http://en.wikipedia.org/wiki/Sea_surface_temperature
@george Smith
“For example, there is absolutely no tendency for an individual molecule that currently has a high KE (velocity) to seek out and target a neighboring molecule, that has a much lower energy and velocity.”
Well sure, it’s not going to seek out slower moving molecules, per se. But it has a greater chance of hitting slower moving targets since they bunch together more.
http://www.realclimate.org/index.php/archives/2006/09/why-greenhouse-gases-heat-the-ocean/
Complete with experimental evidence. As Willis notes there are much better skeptical arguments. As long as skeptics remain UNSKEPTICAL of bogus skeptical arguments the perception will be that skeptics would not accept the truth if it hit them in the face.
GHGs warm the planet. They do not cool it.
Man’s activities increase GHGs, they do not lower them.
Some general truths that are fully consistent with a skeptical position about catastrophic warming.
When you accept these two facts, then you get to join the science debate. That debate is about
1. How much do GHGs warm the planet
2. Can we and should we do anything about increased GHGs.
But when you try to toss out or deny those basic two facts, you dont get to join the debate.
pretty simple. You wanna know why Willis gets to join the debate? Why spenser gets to join the debate, Lindzen? heck even Monckton.. Because they accept the first two.
If you believe those first two, do a little experiment next time you are on a warmist blog. Announce that you accept those two facts.
Excuse me!? (Smokey or Dave – it’s late an I’m not sure which one wrote the comment)
What do you think you’re seeing on GOES (8–15 µm wavelength) IR satellite image?
I ASSURE YOU lakes/bodies of water *do* show up … and imagery color/shading appears to be proportional to temperature …
Maybe another point is being argued, in which case ‘never mind’ … otherwise take a look for yourselves; pick a region with a body of water for display (like the GREAT LAKES. Remember ground obscured by clouds will read cloud top temperature):
http://weather.rap.ucar.edu/satellite/
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astonerii says:
August 15, 2011 at 6:13 pm
“First, should it not be an extremely simple task (for a scientist) to measure how much DLR there is?”
Absolutely. It’s called pyregeometer. Wanna buy one?
http://www.meteorologyshop.eu/Pyrgeometer/ENG_276_EUR_264_1173__.html
A bargain at a mere 5000 euros but if you want to pinch some pence you can wait for the after-Christmas sale in January when they deeply discount the last year’s models to make shelf space for the newer models. /sarc
astonerii . yes there is experimental evidence.
“However, some have insisted that there is a paradox here – how can a forcing driven by longwave absorption and emission impact the ocean below since the infrared radiation does not penetrate more than a few micrometers into the ocean? Resolution of this conundrum is to be found in the recognition that the skin layer temperature gradient not only exists as a result of the ocean-atmosphere temperature difference, but also helps to control the ocean-atmosphere heat flux. (The ‘skin layer‘ is the very thin – up to 1 mm – layer at the top of ocean that is in direct contact with the atmosphere). Reducing the size of the temperature gradient through the skin layer reduces the flux. Thus, if the absorption of the infrared emission from atmospheric greenhouse gases reduces the gradient through the skin layer, the flow of heat from the ocean beneath will be reduced, leaving more of the heat introduced into the bulk of the upper oceanic layer by the absorption of sunlight to remain there to increase water temperature. Experimental evidence for this mechanism can be seen in at-sea measurements of the ocean skin and bulk temperatures.”
“Since the ocean doesn’t glow in the infrared, it seems to me that when a water molecule receives an IR photon, it immediately sloughs off the extra energy through conduction to adjacent water molecules. ”
What? How do you think SST is measured?
_Jim says:
August 15, 2011 at 8:38 pm
“Dave Springer,
Since the ocean doesn’t glow in the infrared,
Excuse me!? (Smokey or Dave – it’s late an I’m not sure which one wrote the comment)
What do you think you’re seeing on GOES (8–15 µm wavelength) IR satellite image?”
Smokey said it, not me. I quickly corrected him.
What are we seeing on GOES? That depends. You have be looking through some pretty narrow IR windows to see the temperature of the ocean. When viewing a spectrograph from above there are a great many step changes across the spectrum. The tops of each step follow a blackbody curve for a different temperature. The highest steps follow the curve of the ocean temperature. Clear sky only of course. You can’t see through clouds.
Dave Springer says:
August 15, 2011 at 7:49 pm
The difference between land and ocean is that it glows a lot less than land does because most of the energy leaving travels as latent heat of vaporization.
The ocean starts from a much lower temperature than the land, in sunlight. One can cook eggs on a rock at noon, when the sea is barely 25C in my region of Greece.
The whole package of energy balance as treated by climatology is a mess, in my opinion. They take two meter temperatures when the ground can be up to 60 and 70C and the two meter 36C, the sea 25C. It is not the air that looses energy to space according to T^4. And all this down welling and up welling confusion is like magicians tricks. There is perfectly adequate thermodynamics to describe all thermal situations accurately. The reason they do this sleight of hand is, in my opinion, that if they take the beaten thermodynamic track, the small increase in the heat capacity of the atmosphere due to the anthropogenic CO2 cannot be beaten up into a bogey through bogus feedback arguments that lead to the energy oven .
The gaseous state has some different properties, where molecule resonances/vibration modes are more pronounced in gas state molecules like water vapor vs liquid.
An intro (for some perhaps) – http://en.wikipedia.org/wiki/Infrared_spectroscopy
Note section on “vibrational modes”; this establishes where WV either absorbs or emits energy in certain bands/wavelengths.
WV atmospheric effects as well as liquid water characteristics on the same webpage:
http://en.wikipedia.org/wiki/Electromagnetic_absorption_by_water#Atmospheric_effects
Of note: “The spectral absorption features of liquid water are shifted to longer wavelengths with respect to the vapor features by approximately 60 nm”
It’s late – maybe I missed something in the discussion prior …
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David Springer,
Finally, a victory for solid scientific argument!
On average, the Earth’s surface (both ocean and land) receives 492 W m^-2, 168 W m^-2 from direct sunlight (mostly visible) and 324 W m^-2 from back radiation (mostly infra-red) from the atmosphere. The problem with Will’s argument is that assumes that soil/rock and vegetation act in a similar manner to sea-water.
Both the land and sea are efficient at absorbing visible light, all be it by different mechanisms, however the land is heated far more efficiently by infra-red light than the ocean surface.
On average the Earth surface (both ocean and land) looses 492 W m^-2, 24 W m^-2 by upward convective transport, 78 W m^-2 by evapo-transportation, and 390 W m^-2 by surface radiation.
Most of the 102 W m^-2 that is lost by upward convective transport and evapo-transportation is lost over the oceans and not the land (even if you allow for their differences in area). Will mistakenly compares this 102 W m^-2 with the 324 W m^-2 atmospheric back radiation, when he
should be comparing it to the net infra-red radiation exchange between the ground and the atmosphere/space i.e. 390 W m^-2 (infra-red radiation from the Earth’s surface) – 324 W m^-2 (infra-red back radiation from the atmosphere) = 66 W m^-2.
It is not hard to see that over the oceans the 102 W m^-2 upward infra-red radiation more than over-powers the net 66 W m^-2 downward infra-red radiation. This is where the energy goes!
Sorry, the infra-red back-radiation may warm the oceans by a small amount but it pales in comparison with the far greater warming that occurs by teh absorption of direct visible radiation
that takes place mostly at the tropics.
Some people seem to be under the mistaken impression that the top few microns will be warmer than the bulk water, but in fact that is wrong. The surface, which acts like a black body for IR light will emit IR very efficiently, thereby cooling the surface.
The “DLR” would keep the surface layer from getting quite so cold, but it is mainly limiting the cooling by radiation that would be occurring. This would keep the top microns of water water than before, but still cooler than the without the DLR.
There also seem to be a misconception that since the visible light can penetrate ~ 100 meters, the heating is occurring ~ 100 m down. IN fact, sunlight will heat the top meter the best, the 2nd meter almost as well. By the time we are to the 100th meter, there will be almost no heating. The top meter will be the warmest (ignoring other details like mixing, other materials in the water, etc). .
Sorry, the second last paragraph should have read:
It is not hard to see that over the oceans the 102 W m^-2 upward energy loss more than over-powers the net 66 W m^-2 downward infra-red radiation. This is where the energy goes!
@_Jim
Further on spectrograph looking from above. Given the tops of the steps follow a curve for a certain blackbody temperature and given we can see through to the ocean surface we can calculate the temperature difference between the ocean surface and any of the lower steps. Given we also know which gases are causing the lowered steps and given we know the adiabatic lapse rate we can determine the effective emission altitude for any of those gases. Pretty neat, huh? I made a comment in another thread where I did the calculation for CO2 and found it has an effective emission altitude at 15um of about 2000 meters above the surface IIRC.
“jimmi_the_dalek says:
August 15, 2011 at 1:52 pm
Indeed, the idea that DLR cannot heat the ocean is one of the spurious arguments that should not be used. There are plenty of others. Far too many comments here claim that the Greenhouse Effect cannot be real “because it is not like a real greenhouse”. Or that it contradicts the first or second laws of thermodynamics. Stick to objecting to the infidelities of computer modelling – there is plenty of uncertainty there – the basic physics is much more secure than some people are willing to concede.
”
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I think this is something to argue. Why is it that the computer models never match reality? The only true answer is that they use incorrect physics or some mistake somewhere. If they correctly modeled the physics of our planet, they should theoritically spit out a good synopsis of weather patterns but alas, they do not. They in fact never agree with each other on local conditions, and globally, well the IPCC itself split the difference and stated 1.5-4.5C. Why is it that they require such large fudge factors in the first place?
The true scientist would have figured this out and realized that the physics was wrong. Go back to the drawing board, find the mistake and plug in over again. No, instead they fudged it. This is important. The part of science and physics is important. The part of getting this correct so that in the future we do not make the same mistakes. The same mistakes applies to a political and/or ideological movement that looks to make energy scarse and drive our economies into the ground. This movement is nothing but an inquisition all over again.
But alas, the physics might be right if the Earth was actually a black body. But we are a water planet. Water is our dominant feature from the oceans to the atmosphere. Since this is the case and the models like I said have never matched reality, we KNOW there is at LEAST one mistake in their physics calculations. I don’t think closing the book on any part of the physics is the greatest idea in the world. Keep an open mind and realize that yes, there is at least one mistake, and I would guess more since greater minds have attempted this issue. I would point most people towards the lapse rate in general (type does not matter…just look at the changes in pressure and how this effects the atmosphere.)
DLR might have a mistake in it, but I am willing to bet that if it does, its a small one. Focus on where the physics is likely wrong (where Dr. Sagen and Hansen got it wrong on Venus for instance) and explore from there. That is where the mistakes are going to be found.
Falsify the physics, and you falsify every GCM out there. Sure, the theory is still supposedly possible, but I think that blow would be enough to settle the science the other way.
Willis, when did you start taking acid again???
“We know the radiative losses of the ocean, which depend only on its temperature, and are about 390 w/m2. In addition there are losses of sensible heat (~ 30 w/m2) and evaporative losses (~ 70 w/m2). That’s a total loss of 390 + 30 + 70 = 490 w/m2.”
A man of your intelligence and learning should NOT be throwing BS like this around. The ocean is NOT losing 390 w/m2. It is losing 390-~320w/m2=~60w/m2 which is far less than the 170w/m2 that it is absorbing. Where that heat comes from for the 30+70 is then quite obvious.
This is the kind of BS that you get involved in when you start ignoring real physics. Now, where is the fabled BACKRADIATION in that equation??
You also mention the air has no thermal mass. The air has enough thermal mass that there would be pretty much no convection if the GHG’s did not transfer their energy to it. It may not hold a candle to water or even the earth, but, it is much more substantial than the thermal mass of the lightweight CO2!!!
So, the answer is equivocal, the LW does NOT heat the ocean, the SW does and the GHG’s spread the heat through the atmosphere or cool the atmosphere depending on the balance at that moment!!! Basically all the DLR goes UP one way or another!!!
Subscribe.
R. Gates says:
August 15, 2011 at 2:37 pm
Indeed I am a heretic, or as it is usually called, a scientist. I can tell a hawk from a handsaw if the wind is in the northwest, and I don’t particularly care what the orthodox view might be. I actually think about things and investigate things and make up my own mind based on what seems logical and reasonable.
For example, we’re pretty sure that averaged 24/7 around the surface of the plane, there’s about 175 watts per square metre of solar energy striking the surface. Might be a bit less or more, but not a whole lot.
We also can say that the ocean is radiating (not total heat loss but radiation alone) almost 400 watts per square metre. Might be a bit more or less, but not a whole lot.
Heat from the core of the earth is estimated to be on the order of a hundredth of a watt per square metre. If that estimate is low by two orders of magnitude, highly unlikely, thats still only a few watts per square metre.
So why isn’t the ocean frozen? Relatively stable ocean temperatures mean that losses and gains must be about equal … so if it’s not IR keeping the oceans liquid, what is?
But I digress …
w.
Dave Springer says:
“The ocean certainly does glow in the infrared.”
Yes, of course you’re right. And you’re right that land emits much more IR than the oceans. That was really the comparison I was trying to make. I should not have said the ocean doesn’t emit IR. Most everything does, above absolute zero.
Just in case some people misunderstand, I had better clarify an important point.
The argument that I have used above involves averages that include both sea and land.
Of course, both the ocean surface and land surface are exposed to ~ 324 W m^-2 infra-red back radiation. The land surfaces absorb virtually all of the 324 W m^-2 and redistributes a large part
to heat subsurface and atmosphere above. Much of this is then re-radiated back to the atmosphere as infra-red light.
The sea surface also absorbs much of the 324 W m^-2 as well. The difference is that this absorption takes place in the top mm or so which is the part of the ocean that is being actively evaporated and transported back into the atmosphere. So little of this absorbed energy actually goes into heating the deeper ocean.
TimTheToolMan says:
August 15, 2011 at 3:25 pm (Edit)
I thought I had dealt with the “it’s not warming, it’s a reduced rate of cooling”, but let me go over it again.
DLR makes the surface warmer than it would be in the absence of DLR. For that reason, in common parlance we say that DLR “warms” the surface. Yes, it is not exactly in accord with what is happening, which is a reduction in the rate of cooling. But when the surface is warmer with DLR than it is without it, how is the DLR not warming the surface?
I find this whole semantic based argument to be without substance, and an attempt to evade the four arguments I made above. It makes no difference to the analysis whether you term it warming or reduced cooling.
And I still haven’t heard you or anyone else explain why the ocean is liquid, what mysterious energy source you claim keeps the ocean from freezing soltd. Losing 400 w/m2 as upwelling longwave, gaining only 170 w/m2 from the sun, here comes the ice age …
w.