Here we are again. Some readers will be mighty tired of this subject, but evidently there is still a lot of uncertainty of measurement, doubt about the validity of concepts and unwarranted certainty in statements around the question of the ability of infrared ‘back radiation’ from the atmosphere to warm the world’s oceans. It’s an important issue, because it forms the backbone of a lot of claims about the effects of the anthropogenic emission of carbon dioxide and other ‘greenhouse gases’.
The principle direction of the flow of energy in the climate system is from the Sun into the oceans, to the atmosphere, and back out to space. But some of the energy leaving the oceans is delayed on its journey to space because it gets absorbed by ‘greenhouse gases’. The main one is water vapour, but carbon dioxide also plays an important role in keeping the Earth’s surface warmer than it would otherwise be. How does it do that? Well, the common ‘layman’s explanation’ is that the absorbed energy in the atmosphere re-radiates downwards as well as spacewards and that makes the surface warmer. The implication is that this ‘back radiation’ heats the land and ocean directly, like a bar fire warms your legs.
But there’s a problem. Water covers three quarters of the planet, and infrared back radiation or ‘downwelling longwave radiation’ can’t penetrate water beyond a few nanometres, far less than the thickness of a human hair. Several explanations are advanced to try to get around this problem, but there are further problems, a compromise and a solution, as we’ll see.
I was surprised recently to notice that fellow sceptic Willis Eschenbach accepts the ‘back radiation heats the ocean’ proposition. Now Willis is an exceptionally smart guy, and I have a lot of respect for his science, so I want to examine the reason he gives for this acceptance and try to deal with it in a way which will enable easygoing, informative and friendly discussion to take place.
The energy being exchanged at the surface of the ocean is notoriously difficult to measure, so these figures are estimated from readings of the longwave infrared energy bouncing around in the air just above the ocean surface. This is a point worth expanding on as it is important for a correct understanding of ‘back radiation’. ‘Downwelling longwave radiation’ doesn’t come in a straight line from high in the sky and hit the ocean surface. The free path length of the photons carrying the energy is very short, and so there are re-absorption and re-emission interactions taking place between photons and molecules of air all the way up and down the atmospheric column.
Fig 1: Changes in air temperature lag changes in sea surface temperature. Click to enlarge
This flux carries most energy immediately above the ocean surface. This is because by and large the ocean heats the atmosphere, not the other way about. This is easy to prove, by comparing time series of the sea surface temperature and the marine air temperature, which lags changes in SST by several months. See Fig 1.
Since the ocean is on average warmer than the atmosphere, the energy flux across the ocean/atmosphere interface is on average carrying heat from the ocean to the air, at a rate of around 66W/m^2. So given the general direction of the motion of the energy, how can infrared energy be pushed into the ocean, when it can’t penetrate the surface further than its own wavelength?
Willis says:
Regardless of the penetration depth, the IR radiation is in fact absorbed by the ocean. Because of the constant motion of the surface due to wind and wave, some portion of that energy is entrained into the mixed layer.
My response to this is that the amount of energy from back radiation mixed down when the wind ruffles the ocean surface is insignificant and anyway that same wind breaking the surface ‘skin’ up permits additional convection and radiation of heat from the ocean to the air, cooling it down.
The only reply I got to this from Willis was another question:
Incoming radiation from the sun ≈ 170 W/m2 at the surface
Outgoing radiation ≈ 390 W/m2 at the surface
If the ocean isn’t warmed by the IR, as both you and Richard Verney claim, why hasn’t it frozen?
I’ll answer that question presently. First I’ll mention that my contention is supported in the literature by a paper written by Japanese scientists 1 who found that at even very moderate windspeeds, the ‘skin’ of the ocean is disrupted and thus allows energy moving up from deeper in the ocean to escape to the air more easily. This plus the fact that warmer water molecules are more buoyant means the energy is heading upwards, out of the ocean, into the atmosphere.
A question I’d like Willis to answer with regard to his statement is this: If “some portion of that [downwelling longwave] energy is entrained into the mixed layer”, how much of the warming of the ocean between say 1993 and 2003 does he think it might account for, compared to the oceanic warming caused by increased insolation due to the reduction in tropical cloud cover estimated by the ISCCP model 2? My contention is that this extra energy entering the ocean from the Sun could account for nearly all the observed oceanic warming, and hence most of the atmospheric warming too. An albedo and solar induced global warming.
Here’s a compromise both Willis and I can, I hope agree on. The energy in the back radiation dances with the evaporating molecules on the ocean surface and heads back up into the air as they rise. So the ~390W/m^2 of longwave radiation from the ocean surface is composed of energies which have had a varying ‘residence time’ in the ocean ranging from aeons to milliseconds. My contention is that the energy from ‘downwelling longwave back radiation’ has only a brief flirtation with the ocean surface, and very little is “entrained into the mixed layer” as Willis asserts, because heated molecules rise. Evaporated water molecules rise particularly quickly, as they are a lot lighter than air molecules, and are thus very buoyant.
Fig 2. Motion of water under waves.
Another reason to believe very little ‘back radiation’ warmed water is mixed down is that if you watch the subsurface eddies created when a wave rolls along a glass tank, the swirling motion which carries solar energy (which penetrates tens of metres into the ocean) down into the mixed layer is some distance below the surface, far below the level downwelling longwave ‘back radiation’ penetrates to, and conduction of heat in water is negligible. See Fig 2. Willis knows all about this from his surfing experience, and I hope he’ll give us further insight into rolling eddies under waves in his comment on this essay.
So now to answer Willis’ question. The reason the ocean doesn’t freeze is because the energy leaving it is balanced with the solar energy it is receiving over the long term average plus the transient energy in the atmospheric ‘back radiation’ flux kissing its surface causing evaporation and hence convection. The important point is to distinguish between longwave energy being emitted by the ocean which is the energy converted to longwave from the solar shortwave which penetrated deep into it, and the longwave ‘back radiation’ derived energy which has only a very brief encounter with the oceanic surface before it is whisked upwards again by the rising of the water vapour molecules it causes the evaporation of. It causes this evaporation very promptly because a large number of joules of energy in the ‘back radiation’ are getting concentrated into a very shallow depth only a small number of water molecules deep.
This leaves us needing the explanation of how the greenhouse effect really works, since if I’m correct, it doesn’t significantly warm the ocean directly with ‘back radiation’. The greenhouse effect operates not by heating the ocean, but by slowing down the rate it would cool at if the greenhouse gases (predominantly water vapour) weren’t there. It has been said that this is ‘splitting hairs’ and that ‘it amounts to the same thing’, but the semantic difference between the idea that back radiation heats the ocean and the idea that it slows its rate of cooling is crucial to a correct understanding of what is happening when we come to discuss the ‘enhanced greenhouse effect’ caused by anthropogenic emission of carbon dioxide.
Extra CO2 in the atmosphere will, all other things being equal, cause the atmosphere to get warmer, by further delaying the escape of energy to space. Warm air expands, and so the atmosphere as a whole gets deeper. It is estimated that the additional ~120 parts per million of CO2 in the air since ‘pre industrial levels’ started to rise significantly in the mid C20th has increased the height of the troposphere by 150 to 200 metres. So as well as the air getting warmer because there are more greenhouse gas molecules in it than there used to be, the Earth and it’s atmosphere also catches a bit more sunshine due to the increase in the diameter of the atmosphere as well. This thicker, warmer atmosphere also slows the rate of cooling of the ocean further by a small amount, because it reduces the temperature differential between atmosphere and ocean surface, and so reduces the ocean’s ability to lose heat by convection.
Postscript.
Not long ago, NASA discovered that they weren’t having to boost low earth orbit satellites as much to keep them on track. It turns out that since the Sun went quiet, the Thermosphere (a nebulous shell of the Earth’s outer atmosphere) has shrunk by around 30% 3. I wonder what effect that has had on the height of the tropopause, because the ocean has been cooling since around the same time; the Sun went quiet after 2004 or so. A cooling ocean is partly the result of less solar energy entering it, due partly to the drop in solar activity, and due partly to the increase in cloud cover measured by Palle et al since 19984. Svensmark effect anyone? But as well as the change in insolation at the surface, the other side of the coin is the rate energy from the ocean escapes through the atmosphere to space. The signs are that the energy balance at the top of the atmosphere has turned negative, and that is due to both less energy incoming, and more energy outgoing, as low solar TSI readings and ongoing higher levels of outgoing longwave radiation show. Correct TOA balance measurement is crucial to our understanding, but currently the error band is three times the theoretical quantity of the enhanced greenhouse effect, so empirical measurement can’t confirm or deny the AGW hypothesis. Since the ocean provides the largest heat storage on the planet, and the top two metres of it contains as much heat capacity as the entire atmosphere above it, it can be used as a calorimeter to indicate the TOA energy balance5, and the level of terrestrial amplification of the solar signal6.
The relative strength of the effects of enhanced greenhouse gas levels and the change in solar activity levels will become clearer over the years ahead, if we measure them as well as we can in an unbiased way, without preconceptions about how climate works.
References:
1: http://www.terrapub.co.jp/journals/JO/pdf/5001/50010017.pdf
2: http://www.climate4you.com/ClimateAndClouds.htm
3: http://science.nasa.gov/science-news/science-at-nasa/2010/15jul_thermosphere/
4: http://bbso.njit.edu/Research/EarthShine/literature/Palle_etal_2006_EOS.pdf
5: https://tallbloke.wordpress.com/2010/12/20/working-out-where-the-energy-goes-part-2-peter-berenyi/
6: http://sciencebits.com/calorimeter
Tallbloke's Talkshop 
I have no formal training in this subject and so far all I have learned agrees with the above analysis. The following link is a favourite of mine though sadly the LWIR penetration depth scale was removed from the right hand scale of the big graph without explanation a couple of years ago.
http://www.lsbu.ac.uk/water/vibrat.html
Water Structure and Science by Martin Chaplin.
What about the heat content of the air and the ocean? AGW says that the greenhouse effect is what’s warming the air at the surface of the earth, but just below is the ocean, which not only contains far more heat than the air but is also warmer than the air. I still find it hard to see how +/- 1.5 watts/sq m of greenhouse gas forcing could overwhelm the influence of this massive heat sink, even though my phenomenological models insist it caused most of the warming after 1970.
I would have thought the oceans don’t freeze over because they are warmed in 3 dimensions, whilst they are cooled in 2 dimensions.
i.e. SW sunlight penetrates down to about 200 metres, but cools only from the surface.
Tally could you please clarify for me your statement that the oceans are warmer than the atmosphere.
I understand oceans contain more energy/heat than the atmosphere, however the mean T of the atmosphere is 15DegC. I would have thought the mean T of the oceans is much lower than that, in the low single digits.
Richard, nice link, thanks.
Roger, As I said near the end of the essay, “the ocean provides the largest heat storage on the planet, and the top two metres of it contains as much heat capacity as the entire atmosphere above it”. This should give pause to anyone who thinks the energy in the air is going to make a big difference to the ocean heat content directly.
Baa, put a wide shallow pan of water in a running 600W microwave and stick that inside a blast freezer which cools the the surface of the water at 700W. Will the water freeze or boil?
The mean T of the sea surface is around 17.5C (from memory). The mean T of the ocean bulk isn’t an issue, because the air and it’s back radiation has no access to it
I have a question for you guys which I asked over on WUWT.
My understanding is that the LWR is in the form of photons and they impact Atoms or Molecules of CO2 (or H2O etc) and impart energy to that atom or molecule, which is in turn re-radiated or passed on by contact with atoms and molecules in a lower state of excitement.
The question that I asked is what happens in a Photon/Photon collision?
Someone answered that neither part had enough energy/mass to do anything, but it is the same energy/mass that can excite a CO2 or H2O atom or molecule.
The reason that I ask is that there is a lot more radiation going up than can possibly be coming back down, so collisions must occur. What happens to the downward photon and it’s energy?
FWIW a paper has just come out that estimates the climate sensitivity at 0.45C. The abstract is at: http://meetingorganizer.copernicus.org/EGU2011/EGU2011-4505-1.pdf. Here’s a quote.
“The line-by-line calculations for sun light from 0.1 – 8 m (short wavelength radiation) as well as those for the emitted earth radiation from 3 – 60 m (long wavelength radiation) show, that due to the strong overlap of the CO2 and CH4 spectra with the water vapour lines the influence of these gases is significantly reducing with increasing
water vapour pressure, and that with increasing CO2-concentration well noticeable saturation effects are observed limiting substantially the impact of CO2 on the warm-up of the atmosphere.”
Hi Roger,
there seems to be a consensus forming around that non-feedback figure. Roy Spencer is in the same ballpark.
AC Osborn. Have a read up on ‘particle-wave duality’ and try not to worry about it. The physicists don’t! 😉
I think Lindzen is too.
A C Osborne, photons are not real, they cannot collide or interfere with each other. There were invented by physicists to get round the radiation catastrophe problem.
Another point about air and water; it is easy to calculate that there is about 6kg of CO2 in an air column on a 1 square meter base, but in the sea under a 1 square meter area there is an average depth of 4,000 metres. From around 1,000 metres down the sea temperature is below 4C, the CO2 solubility curve shows there could be 3 grams of CO2 per litre of water, that adds up to 3kg of CO2 per cubic meter!!!
That works out as rather more than 60 times CO2 in the oceans than the air.
By Jove, temperature, it’s all water, in a symphony and dance of its various forms! What is the size of the ice crystals in a cyrrus cloud, reflecting sun back to space? What is the lag between oceans taking in and releasing heat? How much water vapor is there everywhere, above all the different terrains? How does the efield extending half a mile outward from clouds effect the readings for the aerosols in the atmosphere?
Why don’t they go and model that. But as Freeman Dyson and reasonable people keep pointing out, the models leave everything out, and continue to make preposterous AGW predictions.
Zeke says:
How much water vapor is there everywhere, above all the different terrains?
According to Richard III’s link in the first comment, there is:
“13 million million tons of water in the atmosphere (~0.33% by weight) is responsible for about 70% of all atmospheric absorption of radiation, mainly in the infrared region where water shows strong absorption. It contributes significantly to the greenhouse effect ensuring a warm habitable planet, but operates a negative feedback effect, due to cloud formation reflecting the sunlight away, to attenuate global warming. The water content of the atmosphere varies about 100-fold between the hot and humid tropics and the cold and dry polar ice deserts.”
There is a big difference between ocean and atmospheric heating and trying to understand the bulk effect of the different forms using a static model is nigh on impossible. Air has a low thermal capacity and is a poor heat conductor, while water is a good conductor of heat and has a high thermal capacity. You won’t be kept nice and warm in bed under a wet blanket, nor would a bottle full or hot air keep you warm more than a minute.
My take on this is that the ocean heats and cools from a variety of dynamic processes which vary in a non-linear way, with multiple linked processes involved. There is also turbulence and boundary effects, so I think even a good estimate of what happens is difficult and accurate measurement of the system impossible.
However, it is common sense that the oceans heat the air and that back radiation will doubtless have a small warming effect through conductance and turbulent mixing.
Tenuc says:
back radiation will doubtless have a small warming effect through conductance and turbulent mixing.
Yeah, well that’s my main point. Willis is right that “some portion of that energy is entrained into the mixed layer.”, but it’s not going to anywhere near account for the warming of the oceans in the late C20th. It’s the sun (through less cloud) that did that. And because the ocean is very efficient at squirreling away solar energy, it was never noticed as a solar signal in the noisy surface record with all the ENSO activity going on.
Tallbloke, are you aware of the following from Dr Noor Van Andel which was the basis of a presentation to KNMI http://climategate.nl/wp-content/uploads/2011/02/CO2_and_climate_v7.pdf His finding are based on actual measurements not models. You maybe interested in his thoughts about galactic cycles of cosmic rays affecting clouds.
Keep up the good work
Thanks CF, I’ll take a look when I have a moment.
tallbloke says:
March 3, 2011 at 10:50 pm
“…the ocean is very efficient at squirreling away solar energy…”
Amen to that Rog. This is a major reason why life has been able to thrive so long on this planet, despite having a variable star (which displays a wide variation of energy output over millennial time scales) as the only major heat source.
…Warm body of water with a high specific heat capacity and a network of currents to spread thermal energy towards the poles. Then add a thick blanket of insulating air with a low specific heat capacity to prevent the heat escaping to space.
Without the energy buffering effect of the sea more deep glaciation events would occur and make this a much less clement place to inhabit.
Richard111,
Thanks for the link! I have never come across this before.
It also helps to back up my claim on compression of gases of cold and hot are two completely different things.
I’ve been involved in discussions on this very issue for some time because it is critical for AGW theory.
In the end I have come to the view that instead of warming the oceans the influence of more CO2 and the associated extra Downweling Longwave Radiation (DLR) is limited to the air and simply manifests itself in a miniscule unmeasurable shift in the air circulation systems.
I’ve just had a rather long and acrimonious discussion on the topic here:
http://www.theweatheroutlook.com/twocommunity/default.aspx?g=posts&t=3091
and I think my contentions are currently incontrovertible.
It’s best to start at the end and work backwards to get the gist of my case.
TB.
“But there’s a problem. Water covers three quarters of the planet, and infrared back radiation or ‘downwelling longwave radiation’ can’t penetrate water beyond a few nanometres, far less than the thickness of a human hair.”
I think you’d be wise to check your references here TB. What you seem to describe is ‘conduction by surface contact’ and the ocean surface ‘skin’.
Here’s a reference to EM (insolation) absorption into ocean;
http://books.google.com/books?id=C5kRs1z_CYoC&pg=PA56&lpg=PA56&dq=UV+absorption+of+water+vapour&source=bl&ots=bLYkuKb6z8&sig=ShuCKHswM8g8Axo3FbNG27gSi7w&hl=en&ei=7KqASrLnO8SMjAem5IH2CQ&sa=X&oi=book_result&ct=result&resnum=9#v=onepage&q&f=false
I’m not sure if I’ve posted this here before. However, Figure 2.13 indicates that most of the IR spectra penetrates at least a few metres into the ocean before its ‘extinction’. While I realise that this isn’t ‘back-radiation’, it’s within a similar region of IR.
Hope this helps.
Best regards, Ray Dart.
Hi Steven, and thanks for dropping by again.
I agree with you that when the Earth is viewed as a giant heat engine, it becomes clear that the small amount of increased back radiation is likely negated by mechanisms which are far more powerful in their ability to change the way the Earth maintains its thermal balance.
If Earth can cope with a 25% increase in the output of the Sun over 3.5 billion years I doubt a 0.015% change in its atmospheric composition is going to have a big effect.
Ray,
Near IR solar radiation from the several thousand degrees kelvin solar surface penetrates a few metres. Longwave radiation from the several hundred degree kelvin terrestrial atmosphere penetrates hardly at all beyond its own wavelength. This is well known physics.
Rog
“The greenhouse effect operates not by heating the ocean, but by slowing down the rate it would cool at if the greenhouse gases (predominantly water vapour) weren’t there. It has been said that this is ‘splitting hairs’ and that ‘it amounts to the same thing’, but the semantic difference between the idea that back radiation heats the ocean and the idea that it slows its rate of cooling is crucial to a correct understanding of what is happening when we come to discuss the ‘enhanced greenhouse effect’ caused by anthropogenic emission of carbon dioxide.”
Every skeptic of the tyndall gas effect should read an memorize this. It really is quite simple. GHGs operate by slowing the release of energy from the surface. With no GHG gases the surface would just reradiate. ( ok, heat capacity of the surface material would delay the return) but with an atmosphere of IR opaque gases energy gets transmitted back to space with a delay. The more opaque the gases the higher the effective radiating height. the higher that height is the less rapidly the surface will cool.
Mosh says:
The more opaque the gases the higher the effective radiating height. the higher that height is the less rapidly the surface will cool.
Mosh,
correct. And this is what I said in the main article, though not as clearly and succinctly as you have. I said:
“Extra CO2 in the atmosphere will, all other things being equal, cause the atmosphere to get warmer, by further delaying the escape of energy to space. Warm air expands, and so the atmosphere as a whole gets deeper. It is estimated that the additional ~120 parts per million of CO2 in the air since ‘pre industrial levels’ started to rise significantly in the mid C20th has increased the height of the troposphere by 150 to 200 metres.
So we agree that the greenhouse effect does not work mainly by energy from the atmosphere being entrained into the ocean mixed layer to any significant degree like Willis seems to think, but by increasing the height of the tropopause. Now Mosh, it’s not just a question of the altitude that most of the radiation to space takes place at, but why most of the radiation to space takes place at that altitude.
The reason is that that is where the concentration of water vapour matters most, since it is the main greenhouse gas in the atmosphere, and water vapour is lighter than air, whereas co2 is heavier than air, and is mostly at a lower altitude.
Have a look at this graph of specific humidity near the tropopause (300mb) vs solar variation:
Now, tell me Mosh, just off the top of your head, and without me putting a co2 curve on the graph a la Willie Soon to give you something to get distracted about, what do you think has more influence on water vapour levels near the point of max radiation to space, the Sun, or co2 and other ‘forcings’?
Straight answer to a straight question please.
“The greenhouse effect operates not by heating the ocean, but by slowing down the rate it would cool at if the greenhouse gases (predominantly water vapour) weren’t there”
That is precisely the point that I have been seeking to resolve for some time.
My finding is that there is no evidence that increased DLR changes the temperature gradient in the ocean subskin yet it is that gradient which changes with changes in the rate of energy flow from ocean bulk through the subskin to the skin at the top.Indeed that gradient dictates the rate of upward energy flow as per Fourier’s Law.
What seems to happen instead is that extra DLR warms the ocean skin but the increase in evaporation (which increases upward energy flow) offsets the reduction in the rate of energy flow that would otherwise have resulted from that warming so as to maintain the same rate of energy flow from the ocean bulk to the air above.
There is a baseline temperature gradient in the ocean skin which is set by atmospheric pressure and the enthalpy of vapourisation. If more DLR seeks to disturb that gradient then it fails to do so because of its inability to penetrate beyond its own wavelength.
Thus no change in the upward energy flow despite a warmer skin layer and the ocean bulk temperature remains unaffected which puts the entire effect of more DLR in the air.
In essence the increased upward energy flow from more evaporation negates the slowing of the upward energy flow that would otherwise occur from the operation of Fourier’s Law.
Since ocean surface temperatures control air temperatures the only effect of more DLR will be a miniscule change in the speed of the hydro cycle as the warmed air above the warmer ocean skin adjusts back to equilibrium with ocean skin surface temperatures. That trivial adjustment is wholly dwarfed by natural changes in the speed of the hydro cycle caused by solar and oceanic variability.
Unless it can be demonstrated that more DLR does affect the temperature gradient in the subskin.
Hi Everyone:
Over the last few days I’ve been going back over the data searching for the magic ingredient that explains the SST-SAT differential discussed in earlier threads (SLP, wind shear, number of Republican senators, whatever) without much success. However, I did come across one interesting correlation. If one can believe the data – and I can’t imagine why ICOADS should have made them up – the +/- 1C increase in SST since 1910 is closely correlated (R>0.9) with a 13% INCREASE in marine cloud cover, from 4.7 to 5.3 oktas.
This may seem perplexing at first glance because clouds are supposed to cool things down, not warm things up. But if we accept that greenhouse gases prevent heat from escaping from the ocean rather than warming it directly it maybe makes some sense. Here’s a theory from a non-theoretician. Clouds attenuate incoming short-wave radiation, but they attenuate more outgoing long-wave radiation, so we get more solar heat added to the ocean when clouds are present than we do under clear-sky conditions. Now have at me.
Stephen Wilde: I did go back and read some of your comments on the other site. All I can say is that I admire your tenacity.
Thank you Roger but I can only justify being tenacious until it can be demonstrated with real world data whether more DLR on its own can alter the temperature gradient in the ocean skin.
I suspect not in which case the aspect of AGW theory which suggests a warming ocean bulk from more DLR fails.
If it does then it is me who will have to reconsider.
However, bear in mind that if more DLR does indeed slow down energy transfer from ocean to air then that would offset any AGW warming in the air and given the huge thermal capacity of the oceans any problems would be deferred for millennia.
They can’t have it both ways.
If more CO2 warms the air then fine we have to accept that there is a warming effect in the air alone and instead poiint out that it is miniscule compared to natural variability.That is my position.
If it warms the oceans then we should not have observed any warming of the air so far because of the huge buffering effect of the oceans.
Roger Andrews said:
“Clouds attenuate incoming short-wave radiation, but they attenuate more outgoing long-wave radiation, so we get more solar heat added to the ocean when clouds are present than we do under clear-sky conditions.”
Hmmm.
The problem I have with that is that attenuated incoming shortwave is lost to the system forever whereas outgoing longwave radiation is simply delayed on the way out.
And the former is more energetic than the latter.
So I don’t think you can be right. The net outcome must be cooling but the oceans introduce lengthy and variable time lags.
Furthermore I don’t think GHGs reduce energy loss from the ocean (as explained in my earlier post) only energy loss from the air to space but all that then happens is a miniscule adjustment of the hydro cycle and a similarly miniscule shift in the air circulation systems to regain equilibrium between sea surface and surface air temperatures.
It makes sense to me but it’s an uphill task getting it across to committed AGW believers.
Whoops. I should have said subskin not skin in my post of 4.26 first sentence.
Stephen:
“The problem I have with that is that attenuated incoming shortwave is lost to the system forever”. Maybe this is a semantic point, but energy doesn’t get “lost”. It has to go somewhere, do something.
Let me now ask you a question. SST increases as cloud cover increases. You say my explanation isn’t right (which it probably isn’t). How would you explain it?
Roger, could you tell us something about the way the ICOADS cloud data has been assembled? Are they on deck observations?
I’m sceptical about the value of ‘global series’ constructed from geographically limited datasets using data collection methods susceptible to human subjective bias..
ISCCP satellite data shows a drop in tropical cloud cover from 1980-1998. As you pointed out the other day, most of the insolation to the ocean is in the tropics. More cloud elsewhere may have a heat trapping effect though.
Stephen,
thanks for dropping by, your insights are always welcome here. I’m going to disagree with you on some things you’ve said, but I’ll wait until you’ve expanded a bit further and then formulate my thoughts as clearly as I can.
Ok tallbloke, polite disagreements are welcome since I doubt that I’ve got everything right.
Roger Andrews said:
“but energy doesn’t get “lost”. It has to go somewhere, do something”
Energy reflected by the clouds back out to space is lost forever because it never gets into the Earth system. I regard the oceans as the primary component of the system so solar energy that is denied to the oceans is effectively lost forever. Any effect that it might have on the upper atmosphere whilst it comes in and is bounced out is insignificant.
and
“SST increases as cloud cover increases”
I think it is the other way round. SST increases when the ocean surfaces are in warm mode such as a positive (warm) Pacific Decadal Oscillation (PDO) that generally lasts for about 30 years.
Warmer SSTs increase humidity for more cloudiness all other things being equal. However all other things are not equal. At the same time the jets, indeed all the air circulation systems drift to and fro latitudinally from competing solar and oceanic effects.
So if the sun is active the polar vortex appears to shrink and the jets move poleward which shrinks the polar air masses and expands the equatorial air masses.
That then increases the cloud free zones in equatorial regions to allow more solar energy into the oceans. The energy content of the oceans increases but is not immediately returned to the air especially if the sea surfaces are in cool mode (negative PDO).
Overall the latitudinal jet stream positioning trumps the warm SST/cloudiness relationship by altering the size intensity and position of all the air circulation systems but especially the subtropical high pressure cells which contain descending air and so are free of cloud.
I hope that amplification answers some of tallbloke’s concerns too.
Stephen Wilde says:
March 5, 2011 at 5:00 pm
Furthermore I don’t think [additional] GHGs reduce energy loss from the ocean (as explained in my earlier post) only energy loss from the air to space but all that then happens is a miniscule adjustment of the hydro cycle and a similarly miniscule shift in the air circulation systems to regain equilibrium between sea surface and surface air temperatures.
Hi Stephen. As usual we agree far more than disagree. Our thinking has developed in tandem over the last couple of years and it’s been a pleasure to have your company along the road of discovery.
I’d only caution a little less certainty in the summary. We don’t know exactly how much more evaporation additional DLR causes, or exactly what the temperature differentials across the ocean skin are. But I agree with the broad thrust of your analysis, so this is a minor nitpick really.
I’m off to meet my lady for a beer. keep it coming and mind the store while I’m gone.
Cheers 🙂
Tallbloke:
I guess you’re asking me whether the ICOADS cloud cover series, which is indeed based on deck observations, is any good. Straight answer, I don’t know. But we have to consider the following points:
First, it’s still being used as a basic reference (see Ishii 2004, http://www.ccsr.u-tokyo.ac.jp/~agcmadm/papers/ishii-shouji.pdf p 872 et. seq.)
Second, the CRU TS 2.1 global (i.e. land and ocean) cloud cover series also shows a cloud cover increase since 1900. (http://www.cru.uea.ac.uk/~timm/grid/CRU_TS_2_1.html)
Third, the International Satellite Cloud Climatology Project series (http://isccp.giss.nasa.gov/ISCCP.html) indeed shows an overall decrease in clouds (since 1983 in fact), and this tends to contradict the ICOADS and CRU results. ISCCP, however, doesn’t measure cloud cover directly. Instead it “collect(s) weather satellite radiance measurements and .. analyze(s) them to infer the global distribution of clouds”. I don’t know how reliable a result this would give. do.
Fourth, ICOADS cloud cover is yet another pesky data sets that insists on correlating closely with SST.
So for the time being my null hypothesis is that the ICOADS cloud cover series is correct until someone proves it isn’t.
Tallbloke. Congratulations on a very active talkshop.
The topic started me thinking about the obvious increase in the temperature of shallow water during the daytime. Recently I have been swimming in dams to cool off in the middle of the day and my impression is that surface water is much warmer at midday. I will now have to do some night swimming. But I could also pull out a sensor and do some measuring.
As to whether the atmosphere can impart energy to water consider this experiment. Take a bowl of water and place it in direct sunlight and another and place it on the kitchen table in the shade of the house or alternatively in a Stephenson screen. Monitor the water temperature over 24 hours. Compare water with air temperature and the flux of incident energy from sunlight.
I imagine you will see a strong diurnal flux of temperature in the water that is exposed to direct sunlight.
Alternatively,observe two water tanks, one with a roof and the other without. Monitor the temperature at different levels. Compare with flux of incident energy and air temperature.
It occurs to me that it would be very nice to be able to synthesize the back-radiation effect, ramp it up and measure the water temperature response.
What is the back radiation at night versus the back radiation during the day? Does ‘back radiation’ vary strictly in tandem with incident short wave energy from the sun?
If your bowl of water were to be located under the shade of a large tree what proportion of back radiation would it be subject to?
What are the wave lengths of the back radiation that are due to the atmosphere alone? Measure at night. Do these wave lengths excite water?
Does the common measure of back radiation fail to differentiate between scattered light coming in from different directions and radiation that is due to the atmosphere alone?
“We don’t know exactly how much more evaporation additional DLR causes, or exactly what the temperature differentials across the ocean skin are.”
Hi tallbloke, I think I can clarify the above points a bit.
I think it is sufficient to realise that all the DLR must get used up either by provoking additional evaporation or by making up the energy shortfall when that extra evaporation actually occurs.
According to the enthalpy of vapourisation it takes five units of energy to achieve vapourisation of water but only one unit to provoke it so for every unit of DLR that provokes an evaporative event another four units of energy has to come from somewhere and the energy most readily available is from the DLR itself.
It is not the temperature differential from skin to ocean bulk that matters it is the gradient across the subskin.
Normally a warmer skin would reduce the gradient and reduce the rate of energy flow via Fourier’s Law but the existence of increased evaporation in the skin seems to negate the effect of Fourier’s Law by whisking the extra energy upward for a zero effect on the rate of energy flow from ocean bulk to the ocean skin.
I don’t think the logic is going to convince AGW proponents. We will just have to wait and see when the right sensors become available.
erlhapp says:
March 5, 2011 at 9:33 pm
Thanks erl, yes I think many experiments could be done to test SWR vs LWR and their respective ability to heat water. The fact that they have not been done is quite curious.
As I have said, we do not know the residence time of various SWR entering the oceans, we do not know how this spectrum has fluctuated in the past. If some energy from LWIR enters below the surface, we do not know how much, or the residence time of that energy. If we do not know the residence time of any particular change in radiaton WL, then we do not know how much any given flux in said radiation will change the radiation budget over time.
ISCCP satellite data shows a drop in tropical cloud cover from 1980-1998, this would at first glance appear to be far more global and therefore accurate then deck observations.
Poster George suggests that CO2 as well as water vapor reduce SWR entering the oceans. I noticed that in the conducted experiment discussed at SOD, they did not show the temperature read out of the below surface readings. Any change here could have an offsetting effect on the slowing down of ocean cooling.
As always time and space (geographic location) most be taken into consideration with thermodynamic energy flux.
Stephen, thanks. We all look forward to better instrumentation and more accurate observation!
Erl, thanks for stopping by. I was going to suggest the same experiment to WIllis if he had bothered to come and join the discussion. With me being a Tyke and him a Cowboy, I was going to suggest we use our beer.
I’ve discussed the difficulties in designing such an experiment with David before, but it does seem reasonable to give it a try and see what results we get.
Tallbloke,
Pressure changes have to occur for evaporation to occur.
Second, cloud cover is a double edged sword since it consists of water and solar radiation has difficulty penetrating depending on the cloud density. Lightning is interesting to follow as well. The equatorial regions to about 25 degrees on each side of the equator receives the majority of strikes.
Question:
Does not high altitude haze generate more sunburns?
I would suggest that in the experiment the bowl be submerged so that the sides are not exposed to conduction to better mimic the ocean. There would be many problems, but some clear trends could be observed.
I would suggest the experiment be conducted on a clear day, a cloudy day and a partly cloudy day.
Tallbloke: I’ve been trying to invalidate the ICOADS cloud cover series and haven’t been able to. Other people haven’t been able to either (see http://journals.ametsoc.org/doi/pdf/10.1175/1520-0442%281999%29012%3C1864%3AOTAPAI%3E2.0.CO%3B2). So back to my earlier question. Are the ISCCP cloud cover estimates reliable?
I think it is not just the total cloud cover that is important, but the type of cloud and it’s spacial location as well. Perhaps the different data sets are based upon different assumptions with ICOADS having limited observational data, while ISCCP has better global coverage.
However, it is my understand that the ISCCP cloud cover estimates are produced using a proxy measure for cloud then a computer model is used to covert this to cloud cover. I also think that the model used will have the same basic assumption used by the GCM’s.
Perhaps a better method for understanding cloud quantity, type and geographic distribution is needed before we can develop a better understanding of the vagaries of our climate?
This poem, “Only A Passing Cloud”, sums up my views of the IPCC brand of cargo cult climate science rather nicely…
“When darkness hides the sun from view and shadows move across the blue -never let it worry you.
It is only a passing cloud.
Don’t let people spoil your day by what they do and what they say, it doesn’t matter anyway,
they are only passing clouds.
And if a big blow should descend do not think that it’s the end.
You’ll see when once your round the bend
It was only a passing cloud.”
Thanks to, © Wayne Rickard 2011.
The ICOADS cloud cover series appears to be contradicted at least in part by more recent Earthshine project data which shows increasing cloud cover up to 1985, declining cloud cover from about 1985 to around 2000 and then increasing again more recently:
Click to access Palle_etal_2006_EOS.pdf
I suspect that the ICOADS data is too coarse to pick up shoerter term variations so I prefer the more sensitive Earthshine systems.,
If one does rely on the Earthshine data the variations in cloudiness trend seem to match up with jetstream behaviour so more poleward/zonal jets give less cloudiness and more equatorward/meridional jets give more cloudiness.
The cloudiness changes link nicely to global albedo variations too with albedo having been increasing since cloudiness began to increase around the turn of the century and that is when I first noted that the earlier poleward drift of the jets had started to go into reverse.
That is how I came to the diagnosis that a more active sun and/or a warmer ocean surface drives the jets poleward, intensifies the sub tropical highs and allows more solar energy into the oceans for a net warming of the overall climate system (which in my view must include ocean heat content).
The opposite when the sun is less active or ocean surfaces are cooler.
Tenuc:
“However, it is my understand that the ISCCP cloud cover estimates are produced using a proxy measure for cloud then a computer model is used to covert this to cloud cover. I also think that the model used will have the same basic assumption used by the GCM’s.”
That’s what I was afraid of.
Stephen: The Earthshine cloudiness and albedo data seem to be based entirely on ISCCP. Is this correct?
I don’t know Roger. I never had to look into that because their results fit in with so much else.
Roger Andrews says:
March 6, 2011 at 6:24 pm
Stephen: The Earthshine cloudiness and albedo data seem to be based entirely on ISCCP. Is this correct?
No. The Earthshine project measures the amount of Earthlight reflected by the moon, and deduces the albedo from it.
David,
Yes, and, use an agitator to simulate wave action.
tallbloke, thanks for an interesting post. Inter alia you say:
You also say:
Thanks for that most interesting study. It seems to me like the Japanese guys agree with me, that even at moderate windspeeds the “skin” is disrupted. Remember that “disrupted” means “mixed” …
In addition, you say that “wind breaking the surface ‘skin’ up permits additional convection and radiation of heat”. The Japanese scientists say
Next, I’d asked if downwelling IR doesn’t warm the oceans, why the oceans don’t freeze.
So now to answer Willis’ question. The reason the ocean doesn’t freeze is because the energy leaving it is balanced with the solar energy it is receiving over the long term average plus the transient energy in the atmospheric ‘back radiation’ flux kissing its surface causing evaporation and hence convection.
There’s a bit of handwaving in there, so your meaning is not entirely clear. We know that on average there is on the order of 90-100 W/m2 transferred upwards from the surface in sensible (≈ 30 W/m2) and latent (≈ 70 W/m2) heat. This is in addition to the 390 W/m2 which is radiated per Stefan-Boltzmann.
So your “kissing the surface causing evaporation …” might explain the 70 W/m2, or perhaps even the 100 W/m2. That would mean that the rest is absorbed. So while I have no exact answer to your question above regarding how much is absorbed, we can set a limit. There’s ≈ 320 W/m2 of downwelling IR. If all sensible and latent heat were due to IR (it’s not, but this is the limit), that’s 100 W/m2. So the other 220 W/m^2 is the minimum that’s being absorbed.
Yes, it is possible for a photon to strike a liquid water molecule and break it free. I discuss that at Some of the Missing Energy.
However, if all of the IR directly evaporated water, or even a significant fraction of the IR, then if you shone an IR lamp on a tray of water it should evaporate quickly, while the bulk should stay the same temperature. That doesn’t happen.
Or to take another example, if the bulk of the IR (which is the bulk of the downwelling radiation, solar ≈ 170 W/m2, IR ≈ 320 W/m2) went into evaporation as you say, we’d see lakes going bone dry in months.
It sounds like you are saying that the downwelling IR isn’t warming the ocean, it’s slowing the rate of cooling of the ocean. In radiation terms these are totally equivalent. That’s all the entire greenhouse effect can do, slow down the rate of cooling of the planet.
If you slow the rate of cooling of the ocean, the body of the ocean will be … well … warmer. In common parlance we say that downwelling IR warms the ocean, just as we say the greenhouse effect warms the planet or a blanket warms a sleeping man. In all cases what’s happening is a slowing of the rate of cooling.
Thanks,
w.
Willis Eschenbach says:
March 7, 2011 at 8:37 pm
“If you slow the rate of cooling of the ocean, the body of the ocean will be … well … warmer. In common parlance we say that downwelling IR warms the ocean, just as we say the greenhouse effect warms the planet or a blanket warms a sleeping man. In all cases what’s happening is a slowing of the rate of cooling.”
Excellent illustration Willis. GHG slows cooling and does not add to warming. I feel less cooler all ready. 😎 pg
Hi Willis, and many thanks for finding the time to make a considered reply here.
I think it’s really important to correctly frame the issue around ‘back radiation’ so we can clearly understand what it is, and what it does.
As I mentioned in my article, the path lengths of photons are very short, and the interactions between air molecules ‘upwelling longwave radiation’ and ‘downwelling longwave radiation’ mean that we have a flux of photons zipping in all directions, which on the average is from the ocean surface to the air, at around 66W/m^2.
The equipment we use to measure the radiation coming from the direction of the sea surface is actually measuring the radiation in the air above the sea surface, not the sea surface itself. The question of how much ‘back radiation’ is coming out of the sea surface, and hence how much it is absorbing, is still an open one so far as I can tell. Unless you know of experimental results and equipment for measuring radiation I haven’t heard about?
Rog,
Looking at that chart I would rule out SSN.
1. you have used NCEP reanalysis data. dont get me started on that.
2. I’d prefer a flux number to a SSN number
3. no physical mechanism.
4. no measure of correlation or lead/lag
Simply, I would not reject a well understood physics based theory and explanation with actual equations and actual laws of physics for a “hunch” and a line on a graph.
That should be a straightforward enough answer for you.
WRT willis argument. Note exactly what I said. I said nothing about his argument. Dont infer anything from that
Hi Mosh,
I don’t think the NCEP re-analysis is as bad as has been made out by those who dislike what it tells them.
And sure I have a physical mechanism, a very simple one. Hotter sun – less clouds – warmer ocean – more water vapour getting higher into the atmosphere.
Simples.
Tallbloke:
I’ve been playing around to see if there’s anything the data can tell us about sea-air heat transfer. Based on cross-correlations of short-term (+/- 5 year) fluctuations in different data sets between 1981 and 2001 I have come up with the following:
The dominant short-term (note short-term, not long-term) control on global climate over this period seems to have been sea level pressure in the tropical Pacific. When it changes we get the following chain reaction:
Sea level pressure in the Tropical Pacific drops. About six months later trade wind strength in the West Pacific drops. About three months after that trade wind strength in the Central and East Pacific drops. Coincident with this drop in wind strength SST in the Equatorial Pacific begins to increase, causing an increase in the ENSO Index.
About four months after the increase in ENSO sea surface temperatures and air temperatures above the ocean surface begin to increase globally. About two months after that – i.e. about six months after the ENSO increase – air temperatures over the land surface and in the lower troposphere begin to increase globally.
The process also works in the opposite sense, with an increase in SLP causing an increase in wind strength and a decrease in ENSO etc.
I interpret two things from these results:
1. Sea-air heat transfer in the Central Pacific between 1981 and 2001 was controlled by wind strength.
2. Just about all of the global air-sea heat transfer over this period occurred in the Central Pacific.
Note again that I’m talking about short-term effects here. Long-term sea-air heat transfer probably marches to the beat of a different drummer.
I believe you will find that most of the energy transfer from the ocean to the atmosphere is through evaporation and not through radiation or conduction. When the water vapor condenses energy is then radiated away. The temperature difference at the water / air interface is too small to transfer much energy directly. Cool water can transfer a lot of energy to warm air through evaporation. The vapor pressure at the surface is the most important factor. A very low pressure area in the heart of a cyclone will suck huge amounts of energy out of the sea to power its self. Roger Andrews says; The SLP (Sea Level Pressure) is important to local weather systems. I concur. pg
tallbloke says:
March 7, 2011 at 9:37 pm
When that bug bites you, you just got to live with the sting.
My bible on these matters is Geiger, “The Climate Near The Ground”. He gives the following figures for downwelling IR:
72% of downwelling IR is from the first 87 metres.
6.4% comes from the next 89 metres
4.0% from the next 93 metres.
And so on.
This means that for about a quarter of the downwelling IR, the path length is greater than 87 metres. So it seems doubtful that, in real world terms at least, the path length is “very short”.
I don’t understand this claim. I re-read the Japanese paper above, and they certainly seem to think that they are measuring the surface radiation. Why would they not be?
And since we know the ocean surface temperature, why would we need exact measurements? We know the emissivity is 0.98. We know surface temperature. We know Mr. Stefan and Mr. Boltzmann. What more do we need?
Or you could use MODTRAN, from a metre up, looking down … it says 414 W/m2 in the tropics, 360 W/m2 midlatitudes. I have used 390 W/m2 in my calcs above.
Finally, you still haven’t said why the ocean won’t freeze. Your idea that it goes into evaporation/sensible heat can only explain 100 W/m2 of the difference. You’re still way, way short of the energy necessary to keep it from freezing … where do you say that mystery energy is coming from?
w.
Hi Willis,
I don’t think there is any mystery about back radiation energy quantities, just a mystery around the extent to which it interacts with the ocean.
Some things that are known include:
In still air, the ‘skin’ develops a higher temperature that limits the ocean’s ability to lose heat from deeper down. – This supports my contention that downwelling longwave gets concentrated at the very surface and heat doesn’t diffuse downwards much.
When the wind is blowing, the ‘skin’ gets broken up. – You say that when this occurs, the back radiation is absorbed to a greater extent, and I’m sure you are right, although I don’t think it will get very far down, because the warmer water molecules are more buoyant than the subsurface water molecules. I’m also pointing out, and you know this from your study on the effects of storms on the ocean surface temperature, that as the area of the roughened surface increases, the rate of energy emission is raised, and the rate of evaporation is increased. I suggest it is increased well beyond the average figures you quoted, negating any effect of the small amount of entrainment of heat from the surface into the mixed layer. This is one of the reasons why, as you correctly concluded in your Thunderstorm Thermostat Hypothesis, the effect of stormy conditions is to cool the ocean surface beyond initial conditions.
Looking at the progression of your figures for where in the atmosphere the ‘back radiation’ measured at the surface comes from, it’s probably safe to say very nearly all of it is from the first kilometre of the tropospheric column. In scientist of doom’s articles he posted a couple of plots showing that the exact temperature of the ocean skin wasn’t known. He also agreed with Bryan that the greenhouse effect is, as Mosh also says, due to the raised altitude at which most of the radiation of heat to space takes place. I put it to you that the important action is up near the top of the atmosphere, not so much in the air ocean interaction, which is nearly all one way – heat moving from ocean to atmosphere via convection, radiation and conduction.
The ocean doesn’t freeze because the top 0.05mm is warmed by back radiation (plus a little mixing into the near surface when it’s windy) and the next 4,000,000mm is warmed by the sun. A sense of proportion gives a better idea of the scale of effects.
During solar cycle 23, the near surface temperature in dry parts of the land surface went up 2K, while the seas surface temperature only went up 0.2K. Clearly, the ocean mixes down solar energy, which penertates much deeper into the wave eddy, tidal and subcurrent mixing layer, and this lifted the average temperature of the top 700m of the ocean by 0.1K or so. That’s a lot of energy. far, far more than can be feasibly supplied by back radiation being mixed into the top few centimetres of the ocean.
The best data we have (not perfect!) says tropical cloud was reducing between from the start of the satellite age to ~1998, when it started increasing again. It’s clear to me that the modern global warming was largely due to increased absorption and mixing down of solar energy into the ocean, and released again into the air in big burps called el nino’s. Hence the step changes in temperature noted by Bob Tisdale. This is inconsistent with the notion of a steadily increasing absorption of slightly increasing back radiation into the ocean surface. There isn’t enough energy, and there isn’t enough time.
The other line of evidence which says I’m right about this is the way air temperatures lag behind ocean surface temperatures. You didn’t address this point in your response. The ocean has as much heat capacity in the top two meters as the entire atmosphere above it. The ocean is warmer than the air above it. The convective and radiative fluxes are from the ocean to the air. The tail does not wag the dog.
You are welcome to disagree, but I think we need to consider the big picture here, rather than concerning ourselves with just one aspect of energy transfer. I think that’s where the mainstream climate scientists have gone wrong, and is also how they have bamboozled a lot of people into thinking tiny changes in the atmospheric composition is driving climate change.
Cheers
tb
Roger and P.G. You need to read Erl Happ’s work on pressure changes in the short and longer term. he had an article on WUWT not too long ago, and his blog is linked left.
For comparison with the NCEP reanalysis, here’s a composite I’ve knocked together using the NOAA radiosonde humidity data plus sunspot number from 1948 to the start of TSI measurement, plus TSI from 1978. SSN and TSI in red. Interesting to note the profound effect of the ’98 el nino, and the questionable data prior to 1956.
Still looks like a good match to me though Mosh, so I’d like to know just how bad you think the radiosonde data reanalysis is, and why.
Willis Eschenbach says:
March 7, 2011 at 8:37 pm
…”We know that on average there is on the order of 90-100 W/m2 transferred upwards from the surface in sensible (≈ 30 W/m2) and latent (≈ 70 W/m2) heat. This is in addition to the 390 W/m2 which is radiated per Stefan-Boltzmann…
Hi Willis, I think it is important that we all remain aware of the issues surrounding applying any of the ‘laws’ of physics, which are usually set against a reference frame of ‘ideal’ conditions, to our highly non-linear climate system. We also need to understand and question the basic assumptions that have to be made before these ‘ideal laws’ can provide results which are even a close approximation to what is observed.
Our climate system is never in thermal equilibrium due to the way it is heated by our variable sun and because of the spacio-temporal chaos which is inherent. This results in the paradox there is no such thing as an average climate and the earth never actually achieves an exact energy balance.
Some good stuff about this on the link here (some of the comments are also worth a read).
We need to understand much more of how spacio-temporal systems behave before we can even start to understand if we are making the right assumption about our planets thermal energy flows and how this thermal energy is translated from one form to another.
I have some questions for any that care to educate. According to the chart here; http://www.physicalgeography.net/fundamentals/7g.html average W/m2 insolation in the tropics appoaches 390, and in the subtropics about 240 W/m and the comment below the chart states “The combined effect of Earth-Sun relationships (angle of incidence and day length variations) and the modification of the solar beam as it passes through the atmosphere produces specific global patterns of annual insolation receipt as seen on Figure 7g-1”
My Question is…As this comment states length of day as a factor does it mean that this average is for a 24 hour day?
Perhaps it does as I think (?) I remember Bill Illis stating that the tropics in the afternoon incoming solar insolation is closer to 1,000 W/m2, and any change in SWR entering the ocean here is critical.
According to George E Smith, “standard absorption coefficients for LWIR in H2O are well documented, and suggest that something like 99% of downward LWIR that reaches the ocean surface gets absorbed in about 50 microns pathlength, so you have a heated source that is 50 microns thick, on top of a heat sink, that already has a natural Temperature gradient from surface to deeper waters, and a totally huge thermal mass compared to that thin surface layer (I refuse to call it a skin).”
Willis, if you are here, perhaps you could answer this question concerning the climate models. Do the models assume that the DWLWR heats the ocean as easily as an W/m2 equivalant SWR would?
Also Willlis, what do you think of the following assertion?
At its most basic, “only two things can effect the heat content of any system in a radiative balance. Either a change in the input, or a change in the “residence time” of some aspect of those energies within the system.”
It therefore follows that any effect which increases the residence time of LW energy in the atmosphere, but reduces the input of SW energy entering the oceans, causes a net reduction in the earth’s energy balance, proportioned to the energy change involved and relative to the residence time of the radiations involved and the duration of the change.
Tallbloke, have you confirmed and thought further on this information? From 660 to 3,000 feet (200 to 900 meters), only about 1 percent of sunlight penetrates. This layer is known as the dysphotic zone (meaning “bad light”).
http://www.scienceclarified.com/
I am not certain what part of the solar spectrum reaches this depth, or what percentage it fluctuates in various solar cycles.
Hi David,
That would be the UV end of the solar spectrum getting to that depth, *in clear sea water*. UV kills most single celled organisms and some bigger ones, which is why tropical waters are clearer than at the temperate latitudes.
Tallbloke:
“Roger and P.G. You need to read Erl Happ’s work on pressure changes in the short and longer term.”
Well, I went back and read it (at http://climatechange1.wordpress.com/). ErlHapp has obviously looked into this a lot more closely than I have, but we both find that short-term changes in SST are correlated with changes in SLP and wind. However, changes in SLP and wind don’t explain the long-term increase in SST since 1900 (according to HadSLP2r global SLP is the same now as it was in 1850 and according to ICOADS ocean wind strength is the same now as it was in 1860). Nor do they explain the +/- 110 year periodicity in SST-SAT. As we’ve discussed this periodicity is related to a +/- 110 year solar cycle that appears to modulate the rate of air-sea heat transfer.
Tallbloke, have you read this work by Nasif S. Nahle and if so what does it have any impact on the work that you are doing?
http://jennifermarohasy.com/blog/2011/03/effects-of-gravity-on-the-ir-quantumwaves-frequency/
David said:
“It therefore follows that any effect which increases the residence time of LW energy in the atmosphere, but reduces the input of SW energy entering the oceans, causes a net reduction in the earth’s energy balance, proportioned to the energy change involved and relative to the residence time of the radiations involved and the duration of the change. ”
I like that.
Essentially an increase in the residence time of LW in the air warms the air (but not the ocean) so the only place the extra energy can go is into expanding the tropical air masses and pushing the air circulation systems poleward and allowing more solar energy into the oceans.
BUT
the subtropical high pressure cells will only expand if they are supplied with more descending air from above and that would be provided by intensified convection along the ITCZ as per Willis’s thermostat theory.
AGAIN, BUT
the effect would be miniscule as compared to the same effect from warmer SSTs due to El Nino (or a positive PDO) and a similar (potentially opposing) effect from above due to variations in solar activity affecting the size of the polar vortices.
So the combined effects of bottom up oceanic effects and top down solar effects already have a profound effect on the air pressure distribution as witness the changes from MWP to LIA to date. The effect of more CO2 might be to shift the air circulation systems an unmeasurable distance as compared to the 1000 miles or thereabouts latitudinally as seen in the mid latitudes from natural causes over 500 years or so.
Now if the extra energy were being absorbed by the oceans or if it were being offset by a reduction in the rate of energy flow from the oceans then the effects of post industrial CO2 changes would be reduced even further by the buffering effect of the oceans.
Alarmists cannot have it both ways.
If more CO2 affects the oceans it can have little effect on the air temperatures for millennia. If it is having an effect on air temperatures already then it is not getting into the oceans.
And either way it is insignificant compared to natural variability such that we have hundreds of years to adapt our civilisations.
Tallbloke; Visited Erls’ site and read the posts and comments. Looks as if he has about 90% of the climate drivers figured out. The one thing that I saw missing was magnetic field drivers that cause changes in local atmospheric pressures. The earths oblate spheroid shape should provide a good clue. 😉 pg
Roger, Erl found an ~80 year cycle we think may be lunar related.
Stephen, nice comment, thanks.
P.G. large amounts of kudos to the person who successfully integrates Our work, Erl’s work, Brian Tinsleys work, and Vukcevic’s work. I doubt my poor battered ol’ braincase is up to the job.
It is not nessessary for one person to see the whole elephant as long as we can see all of it together. Even a gang of blind men can figure it out together. 😎 pg
The main problem with integration seems to be in getting the top down effects right.
We have seen the polar vortices (especially the Arctic) shift heavily negative with the quiet sun and it was similarly negative (presumably) to give the equatorward meridionality of the jets in the LIA.
At present I’m pinning the top down effect on atmospheric chemistry resulting from ozone responses to changes in the mix of particles and wavelengths from the sun.
In theory that could incorporate all the other ideas too by way of the system changes that then kick in after the solar mix has changed and affected the ozone quantities to change the vertical temperature profile.
Much of what Erl says could be a description of the ensuing atmospheric changes.
Vuk’s focus on magnetism could be relevent in dictating where charged particles have maximimun ozone effects.
Brian Tinsley’s work would be consistent with the delivery mechanism for the solar effects via the solar wind but I think ozone chemistry is a more likely candidate for the primary response rather than the clouds themselves though of course the clouds will respond to the changes in pressure distribution forced by the changes in ozone chemistry.
Stephen, yes, getting the correct conception of the big picture is important before we get lost in minutiae. One issue is the multiple ways different factors int he climate system feed back to each other as they change. My approach has been to consider where the biggest energy flows are, and work outwards from those.
The ocean shifts more energy to the atmosphere by convection of one sort or another (including the latent heat of vapourisation) than it does by radiation.
It shifts enormous amounts of energy to the higher latitudes atmosphere by currents too.
The radicalization of O2 and N2 to create O3 and NOx may well be a key to many effects.
I was once involved in fume scrubbing of NOx from silicon crystal growing foundries as well as engine exhaust. All creators of NOx. Once O2 & N2 are energized enough to break their bonds (radicalized) they will combine into long chains of NONONONONO> that will break onto NOX units and combine with other N or O radicals until there are no more free radicals left to combine with. This creates a very dark plume. On the ground we get smog. At high levels haze.
Maybe the very high level radiation creation of O3 and NOx is creating a radiation / heat sink. Therefor very high level heating and surface cooling. Em. a built in sun screen. :-0 pg
Thanks P.G. More food for thought.
ionisation of the atmosphere has a big role in local atmospheric opacity values I’m sure. How that ties in with global changes, I’m not so sure. The causes of big general effects on ionisation need to be identified and predicted. I’m pretty sure my graph of specific humidity vs solar variation ties in here somewhere.
That graph of specific humidity vs solar variation looked to me to be the mirror of the temperature. Temperature / humidity are the elements of total energy in the air. As temperature rises and humidity drops, energy remains the same. It is about time the two were included to measure energy in the atmosphere instead of temperature only.
The use of temperature only to measure energy in the atmosphere is a half arse measurement that gives a half arse answer. 😉 If you’re going to be a pain in the arse, do a good job of it. pg
Tallbloke, it seems that you did not read the article by Dr (Ir) Van Andel which formed the basis of a presentation to KNMI here http://climategate.nl/wp-content/uploads/2011/02/CO2_and_climate_v7.pdf and I think this by Kirby of CERN is one of his references but anyway should interest you http://aps.arxiv.org/PS_cache/arxiv/pdf/0804/0804.1938v1.pdf
I like what Willis does, but when one digests Van Andel’s analyses based on real measured data Willis’ comments are just plain wrong. So many seem to have little understanding of thermodynamics (eg lapse rate) and heat transfer (evaporation, convection and radiation)
Keep strong
tallbloke says:
March 8, 2011 at 8:24 pm
Stephen, yes, getting the correct conception of the big picture is important before we get lost in minutiae.
Excellent work Tallbloke.
One question that is haunting this poor mortal.
1 m2 of surface ocean. Surely it’s roughness.
In my mind the wind is a factor causing roughness.
Something tells me that the accounts provide a total area of the oceans may have errors. I believe that large enough to affect the energy balance.
Quotes,
Click to access Cox%20and%20Munk%20Glint%20paper.pdf
In addition to the reflection of the sun’s rays from
the sea surface, there are two other distinct sources of
radiation: (1) the skylight reflected at the sea surface,
and (2) the sunlight scattered by particles beneath the
sea surface. These provide the “background” against
which the sun’s glitter is measured
5.3. Correction for Background
In the following procedure for allowing for skylight
and scattered sunlight it will be assumed that the empirical law for the scattered sunlight is independent of
the roughness of the sea surface, but depends only on
the irradiance H from the sun.
Shadows and Multiple Reflection
Cloud shadows can be allowed for to some exten
from a study of the image photographs
Two complicating circumstances which have no
been considered are (1) the presence of steep valleys i
the sea surface which are hidden from the direct view
of the camera,
or from the rays of the sun, and (2) the
occurrence of multiple reflections. By neglecting these
complications we introduce errors into any computation
involving slopes steeper than one-half the elevation of
the sun. We have largely avoided such errors by confining our measurements to sun elevations above 55°
tallbloke says:
March 8, 2011 at 4:20 pm
Hi David,
That would be the UV end of the solar spectrum getting to that depth, *in clear sea water*. UV kills most single celled organisms and some bigger ones, which is why tropical waters are clearer than at the temperate latitudes.
Thanks, is there any way to quantify what effect a, say 5 % change in the solar spectrum of this UVR reaching these deeper waters would have if it lasted for two or three solar cycles. Asuming an increase of 5% would the energy accumulate every day for all the years the change occured?
Regarding Stephen Wilde says:
March 8, 2011 at 6:28 pm
Thank you Steven. BTW, I sent a message to your site to check into this post, It s right up your ally.
Fernando (in Brazil) says:
March 9, 2011 at 1:50 pm
“…By neglecting these complications we introduce errors into any computation involving slopes steeper than one-half the elevation of the sun…”
Good stuff Fernando, and there must be 1001 changes that happen over any one square metre of sea when examined at any moment in time. The surface sea displays the same turbulence and spatio-chaotic behaviour as is observed in our total highly interlinked climate system.
Because of this, the dynamic ocean surface has no average behaviour, so no wonder we haven’t got accurate calculations regarding the energy levels over time. Bulk temperature estimates can help show the history of the total effect of these myriad micro-changes, but the individual elements cannot be measured and this is one of the reasons GCMs have no predictive power.
Cementafriend: Mea Culpa, only so many hours in a day! I have downloaded it and started reading through, looks good. I did give Svensmark a mention near the end of my piece.
Fernando: welcome, to the talkshop. You have made a very important point. Rough surfaces have a much bigger surface area than smooth ones. To make a better estimate of the area of the ocean surface, we need to know the average height and between crests distance of waves. Not an easy thing to sample!
David: UV is small in terms of the percentage of the TSI it represents. But not all Joules are the same in the way they affect climate. I think it will turn out that U.V. is most important for its effects on biochemistry and inorganic chemistry, rather than for the amount of heat it generates.
Thanks David, it’s nice to see my stuff getting a bit of an airing.
I diverge a bit from Chiefio because a flatteneing of the polar vortices so that they spread out and push the jets equatorwards requires a warming of the stratosphere at a time of quiet sun which is, frankly, heretical at present.
That is why I needed to invoke differential ozone effects at different levels.
Some recent results highlighted by Joanna Haigh support that view in that during the solar quietude ozone levels actually rose above 45km which has been quite a surprise to many. If that is continuing to date then a fundamental component of my hypothesis would be confirmed.
Ok, Tallbloke
I will speculate on the roughness of the sea (the others factors are constant …. I know it’s impossible …. Well, speculation)
Suppose that the surface of infrared emission is greater than the input surface solar radiation.
As the control surface …. TOA. I will observe a negative flow of energy. (not a speculation about OHC x TOA).
The roughness is a function of the winds. The strengthening of a special type of wind in the equatorial Pacific ….. Maybe this is a speculative way to get a La Nina. (UAH 02/2011 -0.02 º C).
Missing energy. (Partially recovered.)
Tallbloke:
If you’re still there.
According to GISS, greenhouse gases have caused an increase of about 1.5 w/m2 in TOA radiative forcing since 1970. At a climate sensitivity of 1C this will have warmed the air at the surface by 0.4C, all other things being equal.
But if back radiation doesn’t penetrate the ocean then the forcing increase will not have warmed the ocean at all. So air temperatures should have increased by about 0.4C relative to SSTs since 1970.
And since 1970 surface air temperatures have indeed increased by 0.4C relative to SSTs.
A crude observational verification of your hypothesis, maybe?
Roger, great observation. The question is, how much of the extra warmth in the air is due to the extra co2 and how much is due to extra insolation due to lowered cloud albedo? The sun warms the atmosphere directly too, especially in humid regions.
But I think the real point is that the atmosphere warms more than the ocean surface does, because of its lower heat capacity. So if the ocean surface goes up 0.3C, the air goes up ~0.6C.
Tallbloke,
Excellent article explaining the so-called “greenhouse effect” (which, of course, bears no resemblance to what occurs in a greenhouse). When I spoke to Dr. Willie Soon, he was generally in agreement that greenhouse gases merely slow down that rate of cooling. This “atmospherice effect” is not, in its truest sense, the equivalent of “warming.”
Now, on to your following statement:
“Extra CO2 in the atmosphere will, all other things being equal, cause the atmosphere to get warmer, by further delaying the escape of energy to space.”
What portion of the extra CO2 is naturally occuring vs. the portion that is human-induced? I would argue that the “warming” caused by the human portion is the equivalent of a fart in a hurricane. Moreover, according to various scientific studies, the impact of increasing levels of CO2 is logarithmic. So eventually the warming effect (i.e. reduction in the rate of cooling) of additional CO2 flatlines and becomes minuscule.
Kirk Myers
Altamonte Springs, Fla.
myers2@earthlink.net
On WUWT:
richard verney says:
March 10, 2011 at 6:29 am
Thanks for the link to your article. I was one of those who was arguing similar points with Willis and I have not seen your article before today. It is an interesting read.
I too respect Willis’ views but he was unable to even begin to explain the physics involved in how heat could be entrained by the oceans given the wavelength of DLR and its penatrative depth and thus become well mixed.
The only point he came up with (which did not answer the question) was that but for GHGs, the oceans would freeze and he referred to a link on scienceofdoom which suggested that without GHGs, the oceans would freeze within about 4 years. The underlying data and codes were not attached to the scienceofdoom article so that that assessment could not be verified. However, as I tried to point out to Willis, it is too simplistic looking at average temperatures and average conditions. The oceans are extremely complex and act as both a huge storage reservoir and a huge heat pump. For example, if one looks at the Baltic, in late summer, the sea temp is 16 to 18C and yet within about 4 months, it freezes over notwithsanding GHGs. There are many parts of the oceans (and inland lakes/seas) that freeze within months and this will tend to give the impression that when viewed on an average basis the seas would freeze within years. However, of course, there are great swathes of the Pacific, Indian Ocean, Atlantic etc receiving immense amounts of solar energy which energy is then pumped around by currents etc. It is almost certainly the case that it is this input and distribution that stops the majority of oceans from freezing over within seasons. Further, one may enquire rhetorically as to what causes the ice to melt/recede on these frozen seas/lakes? It is not an increase in GHCs but rather an increase in solar energy either directly and/or indirectly (via currents/circulation patterns).
I consider it probable that the vast majority of recent warming is due to natural variations and one of the key contenders for this being changes in cloud cover and changes in albedo allowing more solar energy to have penatrated the oceans.
.
Hi Richard,
Thanks for that. In fact, it was your exchange with Willis on the folie a deux part deux thread which prompted me to write the article and invite Willis to respond.
His position and Ira Glicksteins seem quite close, but niether of them seem willing to engage with the issue of the inadequacy of the mixing down of the back radiation warmed ocean surface to explain the rise in ocean heat content in the ’90’s.
The ocean freezing argument misses the real point. If the ocean is re-emitting whatever back radiation flirts with it’s surface in short order, an increase in co2 is not going to affect ocean heat content much, because it’ll just cause a bit more evaporation/convection, which cools the ocean surface.
Cheers
Hi Kirk, and welcome to the talkshop.
The general consensus seems to be that human emissions are responsible for just under half the additional co2 in the atmosphere since accurate records of oil sales an coal began to be collated, in the ’50’s I think. This is based on the d13/d12 ratio, which in turn relies on a steady biosphere assumption. However, the biosphere has grown by 7% in the last 25 years according to some studies. How much this would affect the calculation I’m not sure. Ferdinand Engelbeen is the man to ask.
Thanks, Tallbloke. Excellent Web site, which I plan to visit more often. I spend much of my time on WUWT, Climate Realists, ICECAP, The Reference Frame, JoNova, The Hockey Schtick and several other AGW skeptics sites. I also write my own envirionmental column (although I have not posted a new article recently).
Question: Is it truly possible to accurately determine the differences in signatures between man-made CO2 and naturally outgassed CO2? The powers-that-be seem to have picked CO2 as their atmospheric Satan because, unlike water vapor, it can be subjected to taxation and all sorts of energy controls that inevitably will result in “people control.”
Kirk Myers
Heh, you cynic you. 🙂
Well, it certainly is a more lucrative proposition to tax people for breathing and industry for working than it is to try to tax the sun for shining a bit more. I’m trying to stick to the scientific debate here because the political debate has no real quantifiable answer. It turns out that because we understand so little about long term changes in the oceans that the science issue is hard to quantify too. But at least we get to deal with the heart of the matter by discussing it rationally rather than getting bogged down in political argument.
As I see it, if we correctly recast the scientific debate, then a lot of the basiis and unerpinning for the political differences will evaporate.
Tallbloke:
“The question is, how much of the extra warmth in the air is due to the extra co2 and how much is due to extra insolation due to lowered cloud albedo? The sun warms the atmosphere directly too, especially in humid regions.”
I don’t think we know for a fact that there was a lowered cloud albedo. ISCCP shows a net cloud cover decrease, but it goes back only to 1986 and I’m not convinced it’s reliable. CRU TS2.1 shows a slight increase in cloud cover since 1970, but I’ not convinced that it’s reliable either.
“But I think the real point is that the atmosphere warms more than the ocean surface does, because of its lower heat capacity. So if the ocean surface goes up 0.3C, the air goes up ~0.6C.”
Since 1880 the atmosphere and the sea surface have warmed by about the same amount, and sometimes we even see the sea warming while the air cools. Between 1940 and about 1975 the ocean surface warmed by about 0.2C and the air cooled by about 0.1C.
Hmmm, true, but the third factor is outgoing longwave, and we don’t have any measurement of that before 1975. If you look at short term events like the ’98 el nino, you see air temp rise a lot more than SST. Probably partly due to raised humidity in the tropics though.
Tallbloke:
As closely as I can figure it SAT increased globally by 0.5C during the 1997-1998 El Niño and SST increased by 0.4C – not much of a difference. It seems that only a tiny fraction of the heat buildup at the ocean surface got transferred to the air. Note also that SAT lagged SST by +/- 6 months.
It’s just occurred to me that I should take a look at what happened to SST and SAT during volcanic eruptions. Back on this shortly.
On the unrelated question of how much anthropogenic CO2 remains in the atmosphere, I made my own estimates a few years ago by comparing carbon emissions with atmospheric CO2 content, and came up with 46%. 🙂
Here’s HADsstV2 and UAH. I’ve tried to get them onto the same baseline.
http://woodfortrees.org/plot/hadsst2gl/from:1996/to:2001/plot/uah/from:1996/to:2001/offset:0.15
Tallbloke: Right. Troposphere temperatures increased more than surface air temperatures. (sarc on) This is because the effects of global warming are magnified in the troposphere (sarc off).
[snip inflammatory rhetoric]
Engage with the question of freezing. According to you and Verney, as I understand it, the ocean heat budget looks roughly like this (and don’t nitpick, it’s the big picture)
Downwelling solar absorbed by the ocean ≈ 170 W/m2
Ocean Heat Loss:
Radiation 390 W/m2
Sensible (convection) 30 W/m2
Latent (evaporation) 70 W/m2
According to you and Verney, as I understand it, this gives us a net budget of:
TOTAL GAIN 170 W/m2
TOTAL LOSS – 490 W/m2
NET LOSS 320 W/m2
Since according to your theory the ocean is steadily losing a net 320 W/m2, why hasn’t it been frozen solid for millennia? Once you answer that, then we’ll have something to discuss.
PPS – if your answer doesn’t contain numbers, it’s meaningless. I have asked, where is the missing 320 W/m2. Your answer must contain numbers.
Obviously, the numbers are wrong because they don’t add up. The oceans have not frozen solid for 5 billion years.
Time to find the real numbers, where are they hidden Willis? pg.
A thought occured to me ” how is the radiation from the sea surface taken or determined” are we looking at radiation from the sea surface or from the sea water? pg
tallbloke says:
March 10, 2011 at 3:40 pm
“…The ocean freezing argument misses the real point. If the ocean is re-emitting whatever back radiation flirts with it’s surface in short order, an increase in co2 is not going to affect ocean heat content much, because it’ll just cause a bit more evaporation/convection, which cools the ocean surface…”
Yes, and the extra water vapour displaces other gases and increases the temperature of the air above the ocean. This causes an area of lower pressure resulting in wind – then we’re back to turbulence causing sea surface expansion and wind, both fuelling the evaporation cycle to cool the SST further again.
For what it’s worth, here’s a quick look at GISStemp land & sea vv HADsstV2 SST…
http://woodfortrees.org/graph/hadsst2gl/from:1996/to:2001/plot/gistemp/from:1996/to:2001/offset:0.15
Looks like GISStemp blew a gasket in 2004, and in 2008 it happened again???
Hi Willis,
no apology for the edit. We discuss matters on this blog civilly or not at all.
Here are the numbers you asked for, I’m re-using yours for clarity and to avoid sidetrack issues:
Downwelling solar absorbed by the ocean ≈ 170 W/m2
Downwelling ‘back radiation’ ≈ 320 W/m^2
Total = 490 W/m^2
Ocean Heat Loss:
Radiation originating from energy very near surface of the ocean ~220 W/m^2
Radiation originating from energy in the next 4km depth of ocean ~170 W/m2
Sensible (convection) 30 W/m2
Latent (evaporation) 70 W/m2
Total = 490 W/m^2
Net radiative loss from ocean to atmosphere ~70W/m^2
Please can we discuss the issue of the apparent inability of the additional back radiation from increased co2 to mix sufficent heat into the ocean to account for the increase in ocean heat content during the latter part of the C20th now?
Thanks.
tb.
Hi Tenuc, your plot only runs to 2001?
P.G. Sharrow says:
March 10, 2011 at 6:56 pm
A thought occured to me ” how is the radiation from the sea surface taken or determined” are we looking at radiation from the sea surface or from the sea water? pg
P.G.: As I said in the article I wrote:
“The energy being exchanged at the surface of the ocean is notoriously difficult to measure, so these figures are estimated from readings of the longwave infrared energy bouncing around in the air just above the ocean surface. ”
Willis then mentioned some info on where in the atmosphere the radiation hitting an upward pointing sensor comes from, in comments.
In the ‘scienceofdoom’ articles Willis referred to, the actual ocean surface temperature seemed to be calculated theoretically.
I’m sorry to see the aggro between Willis and tallbloke because I respect both.
Willis’s thermostat hypothesis is in my view entirely correct but as I have said before elsewhere it does not extend to a complete global energy budget solution which is what I have endeavoured to provide in my various submissions across the blogosphere
tallbloke has worked hard to supply a venue for unbiased climate debate and I thank him for that.
The immediate issue is the ocean freezing point arising from tallbloke’s agreement with me that the evaporative process being a net cooling process is capable of negating any effect on the ocean bulk temperature of increased downwelling IR from more CO2.
I have already dealt with that elsewhere.
The fact is that evaporation takes the energy it needs from the most readily available source. If the ocean subskin gets cooler than the ocean skin or the air above it then the shortfall will be taken from the ocean skin or the air above it and not from the subskin so the ocean will never freeze from an increase in downwelling IR.
What happens in practice is that increased DLR heats the ocean skin and thereby increases the rate of evaporation. The enthalpy of vapourisation (at current atmospheric pressure) dictates that for every unit of energy that provokes an evaporative event four more units oif energy are taken from the surrounding environment.
So, the increased evaporation from more downwelling IR is self limiting. One fifth of the DLR provokes extra evaporation but when the evaporation occurs it soaks up the other four fifths of the extra DLR and once the extra DLR is used up it cannot provoke any more evaporation.
The background energy ntransfer from sun to ocean to air to space is therefore entirely unaffected but the extra energy in the air does affect the air circulation systems and the speed of the hydrological cycle.
However the speed of the hydro cycle varies so much from natural solar and oceanic variability that the CO2 effect is insignificant in climate terms.
I hope thatr helps.
Stephen: excellent explanation, thank you.
Yes, I asked the question because the surface tension is a very good mirror for most radiation. The low atmosphere is a fair mirror for radiation, specially the lowest 100 meters. much of the radiation measured could be bounce rather then direct emission without extraordinary care in the sensor system. pg
P.G. Sharrow says:
March 10, 2011 at 6:56 pm
A thought occured to me ” how is the radiation from the sea surface taken or determined” are we looking at radiation from the sea surface or from the sea water? pg
http://www.ghrsst.org/SST-Definitions.html
Definitions of SST within the GHRSST – in work!
The GHRSST has agreed to use CF definitions for SST, and the GHRSST definitions are close to the CF definitons. GHRSST suggests some improvements, by rephrasing as suggested below. These changes in definitions (especially the SSTfnd) are to be endorsed at the XII Science Team Meeting in Edinburgh on 1st July 2011 and will be subsequently provided to CF for revision.
The figure below presents a schematic diagram that summarises the definition of SST in the upper 10m of the ocean and provides a framework to understand the differences between complementary SST measurements. It encapsulates the effects of dominant heat transport processes and time scales of variability associated with distinct vertical and volume regimes of the upper ocean water column (horizontal and temporal variability is implicitly assumed). Each of the definitions marked in the bottom right of the figure is explained in the following sub-sections.
(horizontal and temporal variability is implicitly assumed)
lol
P.G.: how does surface tension act as a mirror to radiation?
Fernando: Thank you! That is the diagram on the scienceofdoom website I referred to above.
Tallbloke:
Went back and looked at volcanic eruptions. I’ll probably be condemned to eternal hellfire for saying this, but I can’t find any evidence that either the 1982 El Chichón or the 1991 Pinatubo eruptions had any significant global impact on either air or sea surface temperatures, even though they supposedly caused up to 3 w/m2 of negative TOA forcing. So now I’m beginning to wonder whether TOA forcings have any impact on anything.
I think the following correlation coefficients (for detrended and smoothed 1980-2000 data) tell us where the heat in the atmosphere comes from:
TOA volcanic forcings versus SAT: R = -0.21
TOA volcanic forcings versus SAT: R = -0.03
SST versus troposphere temps: R = 0.86
SST versus surface temps: R = 0.71
Correction: TOA volcanic forcings versus SST: R = -0.03
Doh! Too many graphs open in my browser – I couldn’t see the wood for the trees.
Here’s the correct graph…
http://woodfortrees.org/graph/hadsst2gl/from:1996/to:2011/plot/gistemp/from:1996/to:2011/offset:0.15
…showing the 2004 and 2008 sudden drop in GISStemp anomaly.
A mirror reflects radiation due to the electronic force fields of the surface “skin” of its’ reflective surface. A very smooth surface reflects “true” and a rough surface reflects”scattered”. Low electron energy allows penetration. Very high “free” electron fields reflect very well. The water surface tension tries to create a very smooth surface that causes very little “scatter” with high reflection of lower attack angles and water hydrogen is “metallic” with high electronic field attached to oxygen with low electronic field thus is selective to wave lengths and energy levels that it permits.
The water molecule interfaces with its neighbors so well as to almost create a solid. This is why it takes so much energy to create the gas state. pg
Roger: see this post: https://tallbloke.wordpress.com/2010/08/05/volcanos-dont-cause-global-cooling/
Tenuc: That’s more like it 🙂
P.G. Fascinating. I learn new stuff on this blog every day thanks to you lot. So quite a lot of the radiation being measured coming from the sea surface could be reflected ‘back radiation’ which hasn’t gone into the surface or evaporated a water molecule?
TB, how do you think the ocean is heated if not at the surface? Geothermal? And why does it matter how far IR penetrates the surface? At what penetration distance do you think it would make a difference? All we need is for the top micron to be warm in order to start things cooking, by whatever means.
Willis’ point was spot on–without atmospheric heating of the ocean it would freeze. In your defense you only contradict yourself, claiming long term equilibrium, which equilibrium could only be arrived at through atmospheric heating. And globally we would see that temp/time lags even out, or no equilibrium could be achieved. That is, being a good heat sink, half the time the ocean heats the air and the other half the sky heats the ocean. If the ocean were always a net emitter of energy it would freeze fast.
Your claim that H2O molecules rise because they’re lighter is worse than the notion that IR hits the ocean directly from on high. Do you think there is a layer of water vapor that floats to the top of the atmosphere? It takes months for gases to mix through the atmosphere, and it all happens through collisions. The only thing the light molecules have in their favor is their faster speed, which does accelerate dispersion through permeable membranes and through the air.
The top film of a warm ocean is hot and dense due to radiation and evaporation. But that superdensity contributes negliigibly to circulation–it cannot compete with wind and wave action or even conduction. But we know the sea heats from the top down–geothermal heat is negligible, and the coldest water is at the bottom.
I discussed that graph elsewhere and found it to be rather interesting as follows:
I’ve just worked out what is wrong with the revised schematic.
It omits the scenario where a strong wind occurs at night.
So,on average globally,a strong wind at night offsets the effect on the subskin temperature gradient of light winds during the day.
That leaves us with light winds at night and strong winds at day.
The schematic shows both those scenarios to be identical.
I am therefore proved right in suggesting that top down effects cannot affect the energy flow from the ocean because the wind effects and diurnal solar effects appear to cancel out leaving the baseline subskin temperature gradient imposed by atmospheric pressure and the enthalpy of vapourisation undisturbed.
So does more DLR change that baseline subskin tempertature?
I would say not because it only affects the air since it cannot penetrate the ocean as does solar energy. So it will warm the ocean skin above the subskin but that then increases evaporaton for a speeding up of the hydro cycle and an increase in average global wind speed.
The faster hydro cycle with more wind and evaporation thereby prevents the warmer skin layer from slowing down the rate of energy loss from ocean to air.
A G Foster says:
March 10, 2011 at 9:09 pm (Edit)
TB, how do you think the ocean is heated if not at the surface?
By the solar shortwave radiation which penetrates tens of metres into it.
you only contradict yourself, claiming long term equilibrium, which equilibrium could only be arrived at through atmospheric heating.
No I don’t. Look at the numbers I just gave Willis. The energy from back radiation can get used up cooling the surface not heating it, as Stephen points out. But the ocean is gaining 170W/m^2 from the sun. It has plenty to spare and still not get colder.
A G Foster said:
“Your claim that H2O molecules rise because they’re lighter is worse than the notion that IR hits the ocean directly from on high. Do you think there is a layer of water vapor that floats to the top of the atmosphere? It takes months for gases to mix through the atmosphere, and it all happens through collisions.”
I understand that a water molecule once evaporated stays in the air for about 48 hours before being precipitated downward as rainfall.
Thus the hydro cycle is in control and the lightness of water vapur molecules is a substantial climate driver.
There is no ‘layer’ of water vapour that rises to the top of the atmosphere but there are multiple bubbles of vapour rich air that rise to the stratosphere (sometimes not even that far) and dump their energy load via condensation at a higher level for faster radiation to space.
A variable speed for the hydro cycle and a variable global albedo from changing global cloudiness and variable rates of energy release from oceans to air are the critical factors missing from all current climate models.
Once they are accurately accounted for I am confident that the effects of more CO2 in the air will prove to be insignificant in the face of natural soiar and oceanic variability.
P.G. Thinking about it some more, it’s obvious that some of the solar shortwave is reflected in water, or we wouldn’t see a reflection in it. So why not some of the longwave too? I wonder what proportion of the back radiation is reflected. Someone must have checked it out?
Tallbloke
Curses! You preempted me again. 😦
However, I’m still left with my question of whether TOA radiative forcings have had an impact on anything. Do you know of any hard evidence that they have? Or is it all basically model-based speculation? (The other day I was enjoying an interchange with Chris Colose over at science of doom, and he more or less admitted that we still really have no idea how large the increase in radiative forcing since 1750 or whenever has been.)
Heh, you did well to get Chris Colose to admit that. I asked him several times on Judy Curry’s site about TOA imbalance measurement error and he always blanked the question.
Have you read the Peter Berenyi thread yet? Won’t take long, and you’ll be a wiser man for it:
tallbloke says:
March 10, 2011 at 9:36 pm Someone must have checked it out?
Maybe yes, maybe no. I am often amazed at how much science is done by armchair investigators based on very little in the dirt research. It is no wonder peer reviewed science is such a mess.
I glad to be of some help as I have learned much through the discussions here. 🙂 pg
P.G. I found this, but no hard figures like Willis would approve of:
http://www.tpub.com/content/aerographer/14312/css/14312_178.htm
“Although some of this incoming radiation from the atmosphere is reflected from the surface of the oceans,most of it is absorbed in a very thin layer of the water surface.The difference between the incoming long-wave atmospheric radiation and the outgoing long-wave radiation from the sea surface is known asthe effective back radiation. The effective backradiation depends primarily on the temperature of the sea surface and on the water vapor content of the atmosphere. The time of day and the season have little effect on effective back radiation, since the diurnal and annual variation of the sea-surface temperature and of the relative humidity of the air above the oceans is slight.”
Thinking about it a bit more, the downwelling longwave is zipping about at all angles from straight down to horizontal, so looking at the graph at that link if the way it gets reflected is similar to solar incoming, quite a lot will be reflected.
Tallbloke:
FYI, this is what Chris Colose said about forcings:
“but keep in mind we don’t actually know what the total forcing is (because of aerosols).”
“No, we really don’t know what the radiative forcing is with high confidence.”
“You can see the large spread in the estimated forcing, most of which is due to aerosols. This is one reason most people don’t like using the 20th century to evaluate climate sensitivity, instead turning to paleoclimate evidence, modeling approaches, etc.”
Seems to be a lot of what comes out of bull’s aerosols in that.
I have great difficulty in philosophy in English.
If friends have patience.
The reasons of TB lead to freezing of the oceans according to Willis.
Here a point of “consensus “…… lol
Over the past 400,000 years….. 360,000 years the oceans were frozen and something like 40.000 years with warmer oceans.
Approximately 9:1
to be continued….
Roger Andrews says:
March 10, 2011 at 11:23 pm “You can see the large spread in the estimated forcing, most of which is due to aerosols. This is one reason most people don’t like using the 20th century to evaluate climate sensitivity, instead turning to paleoclimate evidence, modeling approaches, etc.”
I guess it is much easier if you can make it up as you go along.
P.G.
Hey, I never said that. Chris Colose did.
I think the reason “people don’t like using the 20th century to evaluate climate sensitivity” is that the most you can squeeze out of the 20th century record is 1-1.5C.
Willis Eschenbach says:
March 10, 2011 at 6:25 pm
tallbloke said on tallbloke: back radiation, oceans and energy exchange
March 10, 2011 at 3:40 pm
[Willis’s] position and Ira Glicksteins seem quite close, but niether of them seem willing to engage with the issue of the inadequacy of the mixing down of the back radiation warmed ocean surface to explain the rise in ocean heat content in the ’90′s.
[snip inflammatory rhetoric]
Engage with the question of freezing. According to you and Verney, as I understand it, the ocean heat budget looks roughly like this (and don’t nitpick, it’s the big picture)
Inflammatory rhetoric? You accuse me of not being willing to engage you. I’ve engaged with your cockamamie theory here, as well as on WUWT, and at SoD’s blog. That’s an insult, what, like I’m afraid of you or I have no answer to your vague claims?
I ask for an apology, and I say that of all people on the blogs, I’m perhaps the most deeply engaged. I came here specifically to engage with you on this subject, and I’ve done so. Yes, I was upset, but “inflammatory rhetoric”?
And that gets snipped? You are free to be inflammatory, to accuse me of not being “willing to engage you” as though I’m dodging your brilliance or I’m afraid of your rapier-like wit. And my request that you apologize for your piece of patronizing ugliness gets snipped, with the comment:
no apology for the edit. We discuss matters on this blog civilly or not at all.
No, you don’t discuss things civilly. You get nasty to your guests, you insult them without even noticing you have done so, and then you snip their replies.
Then, after insulting me and then snipping my request for an apology, you just want to continue the conversation as if nothing happened? Do people around you let you do that, insult them, censor their replies, accuse them of not being civil, and then go on as if you had done nothing? Really?
Sorry, tallbloke, but that’s not acceptable behavior with me. I came here as a favor to you, to engage with you on your personal monomania. Having done so, you first refuse to answer my simple question about freezing. Having dodged that, you then accuse me of avoiding your intricate and number-free handwaving.
When I get upset at your nasty accusation that I’m avoiding you, you then hide my words, but claim that they are “inflammatory” and not “civil”.
[That’s right Willis, inflammatory, not civil, I’ll repost what I snipped at the bottom of this reply so people can judge for themselves]
At a minimum, tallbloke, the most generous interpretation is that you have a genius for insulting people without realizing it. I’ll go with that, the idea that you do this deliberately is too much to take, so I’m voting dangerously clueless. And you know what? I’m tired of being the recipient of that. I’ll let you perfect your patchy social skills on someone else.
You have some choices. You can either post this here, tallbloke, or I’ll post it over at WUWT with some interesting comments, and then I’ll censor YOUR reply … your choice.
And you can either apologize or not. Up to you. I don’t really care at this point. I have tried being nice to you several times. Every time, you turn nasty and start insulting me and impugning my motives. I won’t be fooled again. You’re like Ravetz, all hat and no cattle … except he’s polite, and he noticed and apologized when he insulted me.
That’s it for me. I’ll not post here again.
w.
[Here’s what I snipped from WIllis’ previous]
tallbloke, I have gone out of my way to try to explain to you what I believe. For you to say now that I am not “willing to engage” is a slanderous lie.
You cannot explain how, if the ocean is getting 170 W/m2 and losing 490 W/m2 it hasn’t frozen. Yet that is your claim, that IR is not absorbed by the ocean (and thus cannot warm it). Instead, you want to lie that I’m not willing to engage on this issue.
I engaged you on the other thread. I came here specifically to engage you. I have described how I see it in a variety of ways, both here, and at WUWT, and at SoD.
I don’t know if a man without honor can comprehend what this kind of slanderous lie means to me. I came here, to your site, at your invitation, to discuss this. I have discussed it. And now you attack, not my science, but my motives? You are a nasty man. You won’t or can’t answer my question about freezing so you attack me. Where’s your answer about freezing, tallman who talks so convincingly of engagement? Whip out your engagement, give me the numbers, not your handwaving bullshit about some dance of the photons.
Of all the commenters on the web, you accuse me of not being willing to engage? Bro’, you’re way out of line. An apology would be appreciated. Otherwise you’re talking to the hand, I’m done …
w.
PS – You want more engagement than the heaps of time I’ve wasted on this crackpot theory already?
Sorry Roger, I failed to properly attribute. Must have been talkin when when I should have been listenin er readin. pg
Comment from a layman. I can’t say I have learned a lot from reading this thread but I can say I have a much greater appreciation of the DEPTH of the problem in this small corner of the field of climatology. I do enjoy reading the considered comments from posters with different viewpoints. Thanks for that.
Now for a question; I’ve always assumed the sea surface to be chaotic. How do you measure chaos? I can understand different levels of “roughness” but I doubt that would help any calculations. 🙂
I can confirm the visibility of sea water in the tropics, surprising how far down one can see through the water. Is that not reflected light from depth?
Hi Richard, yes sunlight penetrates a long way down into the ocean and illuminates it and warms it. Downwelling longwave radiation from clouds and ‘greenhouse gases’ can’t penetrate into the surface of the ocean more than about 0.005mm. Somehow though, the warmista think this radiation from the atmosphere will heat the bulk of the ocean. The Sun heats the ocean, the oceans heat the atmosphere, the atmosphere bounces the energy around and then loses it to space.
The notion that high-IQ CO2 molecules decide to unionize and downwell their logarithmic warmth into the depths of the ocean is silly nonsense. Compared to the energy surge from the sun, CO2’s warming effect is equivalent to a tick on an elephant’s ass.
Kirk Myers
tallbloke, when you call me a liar, and I object strongly and forcefully to that … which one of us is being “inflammatory”?
I came here as a favor to you. You had made the same inflammatory statement on this thread. I had called you on it. You invited me here to discuss the question. After I got here, you repeated the same lie, that I was avoiding you, unwilling to discuss things with you, unwilling to engage.
Again I ask … which one of us is being inflammatory?
w.
[Reply] I have never called you a liar Willis. In fact I’ve gone out of my way to treat you with kid gloves. If you think that my saying that neither you nor Ira seem to be willing to engage with the question of how much heat from back radiation can get mixed down into the ocean is a dastardly slanderous lying insult, you should take a look at the shit you have dished out on Ravetz, me, and other people and reflect for a while.
Now, I’ve answered your ocean freezing argument three times, including an answer with numbers as you demanded. So please now engage with my question to you and tell me how much of the downwelling radiation incident on the ocean surface you think gets mixed down into, and re-emitted by the ocean, how deep you think it gets mixed, and how much of the increase in ocean heat content during the global warming period 1980-2004 can be attributed to it. And I want numbers in the answer, or, to recoin your phrase, you’ll find yourself talking to the hand.
tb.
Here’s a quote from the Allan and Henderson abstract linked.
Click to access EGU06-J-02677.pdf
” A strong increase in CWV (column intergrated water vapour)
with surface temperature of 3 kgm-2K-1 over the tropical oceans for the period 1979-
2004 explains the reduction of clear-sky SNL (surface net long wave flux – up minus down) with temperature (a surface heating) of 3 Wm-2K-1.”
We know that the world’s temperature went up by approximately 3K between 1979 and 2004 and this caused a drop in SNL WITH TEMPERATURE of 3 wm-2K-1. If my maths is correct, these two figures cancel out and the SNL must have remained approximately the same.
In other words an increase in clear sky CWV caused an increase in DLR which in turn increased the UPLR from the ocean by approximately the same amount. The SNR remained the same.
Does this mean that DLR does not heat the bulk ocean or are there other explanations.
tallbloke, you’ve said:
So … you say that radiation is coming from the top 4 km of the ocean, and other radiation is coming from the “very near surface” of the ocean.
Since radiation can only come from the ocean skin, I’m confused how radiation is coming from energy that’s way below the surface.
Also, you had claimed that the IR was somehow “dancing above the surface”. Now, you seem to be saying that it actually is absorbed into the ocean.
I agree with you that much more of the IR is re-emitted soon after absorption than is sunlight, which warms deeply.
But IR cannot penetrate the human body any further than it can penetrate the ocean … and despite that, when you sit under an IR lamp, you sure get warm.
All the best, my apologies for the hard words. I don’t like being falsely accused of avoiding you when I’ve come here at your invitation and am answering your questions, particularly since you’ve made that same false accusation before. But I could have expressed that with less passion, my bad.
w.
tallbloke, it just struck me that, as is extremely uncommon in climate science, you can test your claim experimentally. Put out two glass bowls full of water. Put an IR light above one. Leave them for 24 hours. See if the body of the water is the same temperature in both bowls.
Comments?
Me, I think the IR warms the sea water because of the amount of time I’ve spent in and under the ocean at night. First, semantics. Does downwelling longwave radiation actually “warm” the earth? No, it slows the rate at which the earth cools. It comes to the same thing, however. Slowing the rate of cooling leaves the earth warmer. The same is true in the ocean.
However, the ocean operates backwards to the atmosphere. At night, the atmosphere quiets down, and becomes stratified by temperature. During the day, it overturns and mixes due to the heat from the surface, at the bottom of the atmosphere.
The ocean is the other way around. Unlike the atmosphere, it is heated from the top, not the bottom. During the day, the ocean tends to stratify with the warmest layers at the top. Both the sun and the IR strengthen this process by providing the most warmth at or near the surface.
At night, radiation starts cooling the ocean surface. At a certain point of surface cooling, distributed columns of descending cool water form, and the ocean starts to overturn. The upper part of the ocean water in the mixed layer moves towards the surface to replace the cooler water leaving the surface in the rapidly descending columns. You can feel those descending columns of cool water when diving, starting a varying amount of time after dark, they’re quite distinct.
On cloudy nights, however, the downwelling IR slows the cooling of the surface. It warms the very top layer of the ocean, reducing the net radiation from the ocean. As a result, the overturning starts later and remains weaker. And as a result of that, the upper part of the ocean water stays warmer.
So. You asked how the IR, which is absorbed just under the skin, can warm the body of the ocean water. It does so during the hidden half of the 24 hours, the night-time overturning, the part people don’t realize is happening. It slows the onset and reduces the strength of the overturning. This prevents the body of the ocean from rotating to the surface and being able to radiate its heat.
As a result, the body of the ocean is warmer than it would be without the IR. And that’s how IR warms the deeper part of the ocean.
(Energy from IR is also mixed down from the surface, of course, by waves, whitecaps, spray, foam, and turbulence. A cohesive “skin” disappears with a wind above 6 m/sec (12 knots), above that wind speed the surface is constantly roiled and mixed and the IR is swept in immediately. Since most of the ocean has some of that list of conditions most days, the effect is not inconsequential, but I don’t have numbers.
It’s not how IR affects the deeper ocean, though, that’s the process I just outlined.)
w.
oops
my post 14/3 should have read “world’s temperature went up by approximately 0.3K” not 3K. This leads to the opposit conclusion. A considerable amount of DLR must have been absorbed into the bulk ocean during this period if Allan and Henderson’s figures are correct.
Willis; Excellent observed science on water column machanics. That stratification and then overturn is unobserved by armchair theory possers. Once in a while someone has to get dirty or in this case wet. I guess an old cowboy is of some value, 😉 kind of like an old dirt farmer. pg
Any period of downward mixing from night time overturning seems not to affect the upward energy flow rate because the temperature gradient in the subskin remains the same day and night.
I guess that since the increased evaporative response is virtually instantaneous the extra warmth in the skin layer is taken away upward quickly enough to prevent downward mixing from affecting that temperature gradient in the subskin.
Comparing a water surface with a land surface doesn’t work because evaporation is more limited from a land surface and so a dry land surface will warm from more increased IR without a commensurate increase in the rate of evaporative cooling.
So in the case of your two bowls of water the temperature of the main body of water in each should remain the same but the one receiving more IR will evaporate away faster all other things being equal.
The cloudiness analogy doesn’t work either because cloud in the open air reduces the evaporation rate compared to that which occurs under an open sky whereas IR under an open sky increases the evaporation rate. Thus comparing the effect of cloudiness with the effect of IR is flawed.
As regards this:
“A cohesive “skin” disappears with a wind above 6 m/sec (12 knots), above that wind speed the surface is constantly roiled and mixed and the IR is swept in immediately”
I would say that with more wind the cohesive skin disappears because the evaporative rate increases and the IR is swept OUT even faster. That is why wind has such a strong cooling effect on the human skin when droplets of sweat are present.
So, increased evaporative cooling prevents downward mixing of energy from IR in all situations. The evidence is the persistent temperature gradient in the ocean subskin.
Thanks Stephen and apologies to Willis that I haven’t found time to respond to his comments yet. It’s been a mad-busy few days both on the talkshop and off. I’ll sit down with the time to do proper justice to this ongoing thread as soon as I can.
Stephen Wilde says:
March 14, 2011 at 8:14 am
Since the skin is constantly radiating, under most conditions the very skin itself will be slightly cooler than the “sub-skin”. I don’t see the connection to night time overturning.
Stephen, let me see if understand you. Your argument is that the IR is not absorbed. Instead of being absorbed, it immediately leaves the surface of the ocean via evaporation. I think this is tallbloke’s idea as well, but correct me if I’m wrong.
The problem is that we know the general size of the average global evaporation, which is about seventy watts per square metre (W/m2).
We also know the general size of the global average downwelling infrared (DWIR), on the order of 320 W/m2.
So if all seventy watts of that evaporation is from DWIR (very unlikely, but we’ll take worst case scenario), then my question is:
WHAT HAPPENS TO THE OTHER 250 W/M2 OF DWIR?
w.
tallbloke says:
March 14, 2011 at 9:57 am
Time is our most precious commodity. I lived too long in the South Pacific to get impatient these days. My baseline assumption is that you are busy juggling life and time and chainsaws and family and kitchen knives and play and random vegetables and work like all of us. Answer when it fits.
w.
Hello Willis and thanks for your reply.
You said:
“The problem is that we know the general size of the average global evaporation, which is about seventy watts per square metre (W/m2).
We also know the general size of the global average downwelling infrared (DWIR), on the order of 320 W/m2.
So if all seventy watts of that evaporation is from DWIR (very unlikely, but we’ll take worst case scenario), then my question is:
WHAT HAPPENS TO THE OTHER 250 W/M2 OF DWIR?”
Why can it not simply remain in the air?
Bouncing around between molecules in the air and only part of the time reacting with the ocean skin.
Going by your own thermostat hypothesis that must be the case because if it went into the oceans that would frustrate your thermostat hypothesis wouldn’t it?
The ocean would provide such a huge buffering effect due to the huge energy capacity of water that your themostat response would
be greatly delayed and diffused yet you see a rapid response to warming of the air don’t you?
The general size of the average global evaporation depends on many different variables averaged out globally including atmospheric pressure, the value of the enthalpy of vapourisation,windiness, humidity and cloudiness so your error seems to be in attributing a substantial proportion of that 70Wm/2 to DWIR.
Only a very small component need be due to DWIR. My contention is that when DWIR does react with the ocean skin all of it is used up in increased evaporation for a zero effect on the energy flow from the ocean bulk. That need only be a small proportion of the 70W/m2.
In order to prove me wrong you need to demonstrate that the temperature gradient in the subskin changes with a change in DWIR.
Only if that temperature gradient changes from a change in DWIR can DWIR affect the energy flow rate from ocean bulk through the subskin to the ocean skin.
It appears that the gradient does not change between day and night so if solar insolation fails to change it then I consider it unlikely that a bit more DWIR will change it.
However I do accept that it is not possible to resol;ve the issue finally until we can measure subskin temperature gradients properly and at present we cannot but I understand trhat new sensors are being prepared with a view to resolving the issue.
In the meantime I remain reasonably sure that the physics of the situation mean that more DWIR cannot warm the ocean bulk either directly or indirectly by slowing the upward rate of energy transfer from ocean bulk to the air above.
Stephen Wilde says:
March 14, 2011 at 11:53 pm
Again, if that’s so, then what keeps the ocean from freezing?
I say the basic numbers look like this:
DOWNWELLING
Incoming solar ≈ 170 W/m2
Downwelling IR ≈ 320 W/m2
TOTAL WARMING THE OCEAN ≈ 490 W/m2
UPWELLING
Radiation ≈ 390 W/m2
Sensible heat ≈ 30 W/m2
Latent heat (evaporation) ≈ 70 W/m2
TOTAL COOLING THE OCEAN ≈ 490 W/m2
Since on average the ocean is warming and cooling at the same rate, it doesn’t change temperature.
Now, you say that some 250 W/m2 of downwelling IR don’t warm the ocean, they “float around in the air” … which means the ocean is warmed at the rate of 490 – 250 ≈ 240 W/m2, and cooled at 490 W/m2.
So why doesn’t it freeze?
w.
Hi Willis,
Up the thread, Stephen said this:
“What happens in practice is that increased DLR heats the ocean skin and thereby increases the rate of evaporation. The enthalpy of vapourisation (at current atmospheric pressure) dictates that for every unit of energy that provokes an evaporative event four more units of energy are taken from the surrounding environment.”
I assume that would happen at or just above the surface?
Logically, if Stephen is right about the 250W/m^2 “float around in the air” proposal, then it never forms part of the energy entering the ocean, so your 490W/m^2 incoming becomes 240W/m^2 and so the books balance.
“Float around in the air”? You’ll have to give me a precise scientific description of that.
But more to the point I don’t understand your math. If the 250 W/m2 do NOT enter the ocean, but just somehow magically “float around” above it, that reduces the heat entering the ocean.
But the heat leaving the ocean is known to be on the order of 490 W/m2, and it is unchanged in your formulation. Which leaves the ocean losing 250 W/m2. That’s a large enough imbalance to freeze the ocean in very short order.
So I still don’t get your explanation of why the ocean doesn’t freeze …
w.
A bunch of that ULR measured is just DLR bounce. We know that the total is balanced, as the ocean does not change much over long periods of time. When I get data that does not match facts I look to errors in data gathering. The noise in day to day temperature changes in any one spot is greater the the overall temperature changes. pg
Willis,
The downwelling IR doesn’t ‘warm the ocean’. It warms only the ocean skin. So as tallbloke points out the books do balance but you have two books.
One book involving shortwave into and out of the ocean bulk, the other involving the DWIR into the ocean skin and out to the atmosphere.
Unless the temperature gradient in the subskin changes as a result of more DWIR you cannot transfer entries between the two books.
P.G. Sharrow says:
March 16, 2011 at 4:28 pm
Absolute nonsense. The absorptivity of the ocean for IR is around 98.5%, so reflectivity is only 1.5%. This is why I keep saying give me the numbers. This is handwaving of the highest order.
w.
Stephen Wilde says:
March 16, 2011 at 4:49 pm
Two sets of books? The ocean skin is not part of the ocean?
Well, we appear to be getting somewhere. Before, the claim was that the IR didn’t enter the ocean, it did some kind of dance above the surface. Now, we seem to be agreeing about
However, you’re still not considering the sizes of the flows. Because saying things like “DWIR into the ocean skin and out into the atmosphere” doesn’t mean anything.
I have both explained and discussed how the temperature down deeper changes as a result of DWIR. DWIR slows the cooling of the bulk ocean by delaying and slowing the overturning. As a result, the bulk ocean is WARMER than it would be without the DWIR? Is this so hard to understand?
If you think that the ocean is not overturning at night, or that the DWIR doesn’t slow down the overturning, you’ll have to explain why.
Next, suppose we try keeping two sets of books as you suggest. One is for the top mm of the ocean. The other is for the rest of the mixed layer. You say there’s no exchange between the two, what was it, “you can’t transfer entries between the two books”.
But the bulk ocean can only cool via the skin. So for the bulk ocean to cool at all, the transfer of the energy must go:
Bulk ocean —> Skin —> Atmosphere (radiation, sensible, latent heat)
It CANNOT GO
Bulk ocean —> Atmosphere (radiation, sensible, latent heat)
The only path for energy to leave the ocean is via the skin. So the idea that we can keep two separate books simply won’t work. We have to “transfer entries [heat] between the two books”, otherwise the bulk ocean could never cool.
w.
The ocean skin is separate from the ocean bulk because the ocean bulk is buffered from the ocean skin by the subskin.
As long as the temperature gradient in the subskin remains constant the rate of energy flow from bulk to skin does not change.
Apparently that gradient does stay constant on average globally whether by day or night and the reason is that the gradient is set by atmospheric pressure and the properies of water and air and not by events above and below.
There may well be overturning of the ocean but with a zero effect from more DWIR because ALL the DWIR must be used up in increased evaporation PLUS covering the energy shortfall from its own extra evaporation.
So there are two sets of accounts as follows:
i) Shortwave gets past the ocean skin to heat the bulk and the speed of exit is primarily driven by atmospheric pressure and the density differential between air and water. Variations occur within the bulk ocean from energy redistribution within the water and from evaporation changes caused by wind or cloud or by changes in solar input but the gradient through the subskin stays the same.
ii) DWIR fails to get past the skin and goes straight to extra evaporation with nothing left over. The warming effect of the skin which would normally slow down the rate of energy transfer from below is exactly countered by a faster upward energy flow from the skin.We know that because of the constancy of the temperature gradient across the subskin.
So overall the books balance and the bulk ocean neither cools nor warms any faster from changes in DWIR.
The speed of the hydro cycle does however change in order to maintain sea surface/ surface air temperature equilibrium but the effect is miniscule compared to natural variability.
Think of a tributary joining a river. The tributary adds volume to the river but does not alter the flow rate and in particular it does not alter the flow rate in the river above the junction point. Just as the river flow above the junction point is dictated by gravity so the basic flow rate from ocean to air is dictated by atmospheric pressure.
DWIR adds volume to the upward energy flow from the ocean skin into the air but does not alter the rate of flow from the ocean.
If that doesn’t help you to see it I don’t think I can go further.
Some useful references on the absorption of electromagnetic radiation by water
http://omlc.ogi.edu/spectra/water/abs/index.html
From:
http://omlc.ogi.edu/spectra/water/
Stephen Wilde said
I’m not following this at all. You seem to be claiming that the bulk ocean can exchange energy directly with the atmosphere, without going through the skin. Also, why is the speed of exit proportional to pressure and density differences?
I’ll continue to say this until you get it. DWIR is ≈ 320 W/m2. It cannot all go “straight to evaporation with nothing left over”. Total evaporation is only on the order of ≈ 70W/m2, so there WILL be some left over.
Finally, you keep referring to the temperature gradient “across the sub-skin”, and claiming it “stays the same”. A citation would be useful in that regard. My experience of the ocean is that very little “stays the same”, particularly from day to night.
I’ve explained the overturning. I’ve explained how DWIR warms the bulk ocean by delaying and slowing the overturning. You’ve been asking for the mechanism. I described it in detail above.
I’ve also explained several times why all 320 W/m2 isn’t going into evaporation. Total evaporation is way too small, it is much less than 320 W/m2. We know that from two directions. One is the direct measurement of open-pan evaporation trays, and things like small lakes. The other is that what goes up must come down, and we have a reasonable handle on how much rain and snow falls every year. The 70 W/m2 represents about a metre of evaporation (or precipitation) per year averaged around the globe.
If evaporation really were 320 W/m2 as you claim, global average rainfall would have to be four and a half metres per year. Average. Sorry. Our numbers for precip have wide confidence intervals, but nowhere near that wide. I’m not sure it rains that much anywhere, maybe on Kauai in Hawaii, but not many places. Suva is very wet, and it’s three metres per year.
Here’s another way to think about it. You would agree, I believe, that evaporation cools the bulk of the ocean. In other words, if there were no evaporation, the ocean as a whole would be warmer. That seems obvious. The sunlight heats the ocean deeply. If it can’t evaporate some of it, it must warm up until it radiates an additional 70 W/m2 that previously were lost to evaporation.
You can test this as well. Put out two pans of water in the sun, and put a few drops of oil into one to form a monomolecular oil film across the top, removing the water’s ability to evaporate. The bulk of the water in the pan with the couple drops oil will be warmer than the bulk of the water that is free to evaporate.
But evaporation, just like DWIR, can only affect the top millimetre of the ocean … so if removing evaporation can warm the bulk ocean by just affecting the top skin layer, why do you say the DWIR can’t do the same??
Thanks,
w.
Hi WIllis. You said:
“I’ll continue to say this until you get it. DWIR is ≈ 320 W/m2.”
Except it isn’t. Or at least not directly downwards. According to your own statements upthread, 95% of ‘DWIR’ is being emitted in the first kilometre above the ocean surface. And the ‘DWIR’ is emitted at all angles from straight down to sideways. The shallower the angle, the more likely it is to be reflected rather than absorbed when it hits the ocean surface.
How does a radiometer tell the difference between emitted and reflected photons?
It can’t.
When I challenged scientistofdoom to provide actual measurements of emitted energy, all I got was lame excuses about how expensive the equipment was. In terms of the question of how much of the radiation measured as coming up wards from the direction of the ocean surface is actually being emitted by the ocean and how much is being reflected off the surface, it doesn’t matter how expensive the equipment is, if it can’t differentiate between the two.
Can you help us out on this and point us to actual measurements which describe exactly what is being measured?
I’d be grateful if you could take this question on as distinct from the discussion you are having with Stephen.
Thanks for your continued contribution here.
tb.
Why does the 320 W/m2 all have to go to evaporation ?
I did misstate something there. Once the DWIR reacts with the ocean skin the temperature of the skin rises and there is an increase in evaporation but there is also an increase in upward radiation, convection and conduction. I had developed the habit of ignoring those phenomena in order to simplify matters.
The net combined effect is always to take energy out of the water faster than it comes up from below so that the subskin cools to below the temperature of the ocean bulk.
If DWIR reduces the rate of energy flow from the ocean bulk to the skin then it has to reduce that effect and change the gradient in the subskin but as far as I can see it does not do so.
The important point is that however one cuts it ALL the DWIR does go back up into the air again without affecting the basic energy flow rate from ocean bulk through the subskin to the skin and thence to the air.
The river/tributary analogy should be helpful in visualising that.
As for the gradient in the subskin see here:
https://www.ghrsst.org/SST-Definitions.html
The baseline gradient through the subskin set by atmospheric pressure is shown when there is no wind and no sun so you will see that the gradient is identical when there is sunshine neutralised by wind by day or a lack of sunshine and no wind to further cool the water surface by night.
The relevance of atmospheric pressure is that pressure determines the value of the relationship between the amount of energy required to evaporate a molecule and the amount of energy taken up when the molecule evaporates. Under existing atmospheric pressure the ratio is approximately 5 of the latter to 1 of the former due to the enthalpy of vapourisation of water.
That is what gives evaporation the power to mop up any DWIR that does not go back upward as radiation, convection or conduction.
Thank you for giving me the opportunity to correct that inadequacy in my description.
“if removing evaporation can warm the bulk ocean by just affecting the top skin layer, why do you say the DWIR can’t do the same?”
Simply because extra DWIR increases evaporation, radiation, convection and conduction with nothing left over to affect the upward energy flow.
Contamination such as oil on the surface and insulation from cloudiness above will reduce evaporation but extra DWIR under an open sky increases it enough to mop up any DWIR left over after enhanced radiation conduction and convection have done their bit.
Stephen Wilde says:
March 17, 2011 at 8:00 am
“…Simply because extra DWIR increases evaporation, radiation, convection and conduction with nothing left over to affect the upward energy flow…”
It is likely that the quoted amount of energy used for rate of evaporation is way too small as far as the ocean is concerned. The boundary layer between air and see is an area of much turbulence which dynamic exposes a greater surface area for the evaporation process. We fail to understand how the surface area of the oceans can vary over any delta t due to turbulence, wave size and spray.
Good science is impossible without good data!
As I’ve been saying:
http://scienceandpublicpolicy.org/reprint/the_associate_of_albedo_and_olr_radiation_with_variations_of_precipitation_implications_for_agw.html
“We anticipate that a doubling of CO2 will act in a way to cause the global hydrologic cycle to increase in strength by approximately 3-4 percent. Our analysis indicates that there will be very little global temperature increase (~0.3oC) for a doubling of CO2, certainly not the 2-5oC projected by the GCMs.”
“It is possible for the troposphere to gain energy from increases in CO2 and to simultaneously enhance its radiation to space to largely balance out all or most of the CO2 energy gains. ”
“Observations of upper tropospheric water vapor over the last 3-4 decades from the NCEP/NCAR reanalysis data and ISCCP data show that upper tropospheric water vapor appears to undergo a small decrease while IR or outgoing longwave radiation (OLR) undergo a small increase. This is opposite to what has been expected from the GCMs. These models have erroneously exaggerated the magnitude of the water vaporfeedback. They have also neglected the strong enhancement of albedo which occurs over the rain and cloud elements.”
TimTheToolMan says:
August 17, 2011 at 3:02 am
Willis writes : “Oh, please, I’m not “pleading” for anything”
I could count the number of times you asked people to refute your points. It was more than once…but meh. waste of time.
Willis writes : “You agree, for starters, that DLR a) is absorbed by the ocean”
If by “ocean” you mean the top 10um of ocean’s water molecules, then yes. However you follow up with “What I don’t understand why “conduction cannot happen”.” because you want the conduction to be downward into the bulk and it just doesn’t happen. The location where the DLR is absorbed is colder than the underlying water. It would break the laws of thermodynamics for any “heat” to conduct downwards. Not to mention the fact there is no excess here anyway. It is, as I said, the coldest place.
Willis writes : “As a result, the skin almost always runs a bit cooler than the water underneath it, with the predictable result—the very surface skin water is always radiating, cooling and sinking a mm or so, then warming from the warm waters below, and rising again.”
Get thee back to school Willis 😉
In the skin layer, its conduction not convection that transmits energy.
eg From “Cool-skin simulation by a one-column ocean model – Chia-Ying Tu and Ben-Jei Tsuang”
“Molecular transport is the only mechanism for the vertical diffusion of heat and momentum in the cool skin and viscous layer”
Willis writes : “During the day, sunlight striking the ocean is absorbed most at the surface.”
I’m not quite sure what you’re saying here. There is a temperature profile that DSR creates as its absorbed in water. Most is absorbed not far below the surface and progressively less makes it deeper but its over meters not really “at the surface”. Or at least thats probably not how I’d descibe it in the context of this conversation.
Willis continues : “If the DLR is warming the skin itself, that absorbed solar energy can’t be moved as easily to the skin and radiated/evaporated away.”
Using what physics do you claim this? If there is excess energy being imparted from the sun, the warm water will convect toward the surface and produce/increase the “hook”. The SST increases, Stefan-Boltzmann kicks in and the rate of radiation increases. More is lost to space and to evaporation and the balance is maintained.
Moving along to the second argument (its not worth addressing the warming of the land part. I think you’re just being argumentative)
“I would agree except for the “immediately”, it suggests that it is re-radiated. It is not re-radiated in any sense.”
Re-radiated as a term is wishy washy, I agree. But I think you know what I mean, the DLR is radiated back up pretty much at the same rate its radiated down and I’m not saying anything about individual photons and where they came from or anything like that.
Over at the Science of Doom, SoD calculated that there is about 42J/m2 heat capacity in the topmost 10um layer of the ocean. We know from the Minnett experiment that clouds can increase the DLR by around 100W/m2. We also know from the Minnett experiment that the surface temperature (relative to the 5cm below surface temparature) changed by around 0.5C at most and even though I disagree with their reasoning, it does put an upper limit on any possible “DLR heats the skin” effect.
And using those values that upper limit is reached in a little less than 0.25 seconds to potentially “heat” the surface. If you believe thats what happens then you need to explain where this energy goes after 0.25 seconds and you need to do it within the laws of thermodynamics. Hence its not conducted down. Its not radiated down. Its not convected down (unless you want to try to make proper arguments for any of those) and instead it must be radiated upwards.
Anyway moving right along and this post is already way too long.
Willis writes : “You can call it what you want, warming, or slowing the cooling, I don’t understand the difference.”
I will indeed call it “slowing the cooling” because thats what it is. I think its important to actually understand the processes behind the numbers and I know thats how you feel too. You wouldn’t have bothered with your recent posts on thunderstorms if you’d felt their effect was adequately wrapped up in the coarse averages the AGWers use.
Stephen Wilde says:
August 17, 2011 at 1:36 am (Edit)
Willis said:
“the actual skin surface of the ocean is almost always slightly cooler than the water immediately below. This is because the surface is cooled by evaporation, conduction to the atmosphere, and radiation.
As a result, the skin almost always runs a bit cooler than the water underneath it, with the predictable result—the very surface skin water is always radiating, cooling and sinking a mm or so, then warming from the warm waters below, and rising again. The very surface is constantly being replaced by slightly warmer water from underneath in a very thin skin-based circulation layer. In this way the heat of the ocean makes it to the surface to be evaporated away.
With this constant interchange, with water surfacing, radiating, sinking a mm or so, warming, and rising again to the skin of the ocean, the DLR striking the surface has the same effect it has at night. It slows the thermal circulation, this time the thin vertical circulation at the very surface. Again it slows the motion of the bulk heat to the surface to cool. As a result, the bulk ocean is warmer than it would be without the DLR.”
I don’t agree with that interpretation.
The 1mm deep cooler ocean skin acts as a buffer between the effects of incoming DLR on the topmost molecules and the flow of energy coming up out of the bulk ocean and into the skin from upward convection and conduction (originally from solar input).
All the ‘circulating’ is therefore contained within the skin and does not affect the rate of energy flow from the bulk below and nor does it allow energy to move downward into the bulk. It is an entirely separate process from ‘normal’ ocean mixing.
The interface between the skin and the bulk is therefore the point at which the DLR effect reduces to zero. The depth of that interface and the temperature differential across it is dictated by the flow balance between the layers that is required to negate the DLR effect.
More DLR actually increases the speed of the process within the skin to prevent any effect on the flow rate up from the bulk. The process is self limiting because once all the DLR has been used up there is no more acceleration of the process.
Given that evaporation mops up five times as much energy as is required to provoke it the idea that there is any energy left over to go into the ocean bulk must be wrong.
So DLR does not warm the oceans nor cool the oceans. The energy transfer process from those warmed topmost molecules increases up through the atmosphere to space via more upward radiation convection conduction and evaporation in a self cancelling exercise because of the buffering effect within the ocean skin.
The consequence is a miniscule adjustment in the surface air pressure distribution as the atmosphere adapts to the changed rate of upward energy flow.
GHGs slow down energy loss from atmosphere to space but the whole package of available negative response mechanisms (with the phase change from water to vapour as an essential component) then accelerates it again for a zero or near zero net effect. The ocean bulk remains unaffected.
Alexander Duranko says:
August 17, 2011 at 2:58 am (Edit)
Sorry Willis, but DLR is only half local radiative heat transfer. What matters is ‘DLR-ULR’.
DLR on its own is a measure of IR impedance. If an atmosphere had no greenhouse gases, it would have near zero IR impedance; the optical depth would fall to near zero because there would be no optical scattering [absorption, re-emission by other GHG molecules in local thermodynamic equilibrium – remember there may be no thermalisation of IR energy]. So, you’d need low ground temperature to radiate a given amount of energy to space.
This analogy is quite close to what happens in metals when you alloy them. The difference in the way the solid solution atoms’ d-shell electrons interact with the conduction band causes the electrons to scatter thus increasing path length and resistance/impedance so you need a higher potential difference to pass a given electric current for an alloy than a pure metal.
The reason why clouds have much higher DLR than moist air is because they have very high IR impedance. The droplets have dissolved lots of the local CO2. Water and CO2 band IR energy is strongly absorbed and scattered. Because the absorptivity/emissivity is high [c. 1 compared with c. 0.1 for moist air] you get a lot of localised DLR. Because a higher proportion of the IR energy being emitted by the ground/sea is needed to offset that higher DLR, you lose less heat from the ground until its temperature rises. That’s why at night, the sudden appearance of a cloud causes local warming.
But the DLR doesn’t do any actual work. Less heat is lost from the ground until the sum of radiation and convection from the ground and the conduction in the ground change exponentially to a new local equilibrium.
Here’s another view: you’re on the beach and air temperature is 25°C but because the wind speed is high, lots of heat is lost by convection so the sand is only at say 30°C when without convection it would be c.70°C. So, you put up a wind break, sand temperature rises to 45°C and you get pleasantly warm lying on it.
Because [assuming 0.85 emissivity] radiative heat transfer has increased by 86W/m^2 to give constant convection plus radiation, assuming half that extra IR energy is absorbed/scattered by the atmosphere back to the ground and everyone else has put up windbreaks [imagine the Sahara] DLR will rise by 43W/m^2. But that is just the result of the IR impedance causing higher radiative potential for a given power transfer. There is no new energy input to the ground.
DLR can do no work. DLR is a measure of IR impedance. Assess the problems as coupled convection plus radiation.
Willis Eschenbach says:
August 17, 2011 at 10:46 am
What we do know is that however the photons dance, it can’t be driven by more than about a quarter of the DLR. That leaves the rest to warm the top mm of the ocean …
Regarding your “dance of the photons”, you’ve never explained exactly what it is. Somehow your theory (IIRC) had to do with the photons never actually hitting the water surface.
But we know that at least three quarters of the DLR is radiated as thermal radiation. And to be emitted as thermal radiation, first the DLR it has to be converted to thermal energy … making the surface warmer than it would be if there were no DLR
I don’t see any dancing photons in that. To be radiated as thermal radiation at a different frequency than the incoming energy, the DLR must be first converted to thermal energy, which warms/slows the cooling of the surface.
They can’t just dance above the surface.
Hi Willis. I can see a few different possibilies which would account for your observations here. Evaporated molecules form an invisible mist above the ocean surface. The sub visible droplets formed have a much bigger collective surface area than the ocean surface. These droplets become more highly thermalised by radiation emitted both from above and below. The hotter they get, the more buoyant they become, until they rise high enough to cool enough to condense and become visible clouds or a sea fret just above the water. How cloud condensation nuclei grow is a big unknown that Jasper Kirkby and his colleagues are currently working on. We know the gases emitted by decaying plankton which form sulphuric compounds play a part as well as GCR’s.
PS – Truly, I don’t care what you call it. If a room is cold because a door is open to the frozen outdoors, when you close the door the room gets warmer. You can say closing the door warms the room, you can say closing the door slows the cooling of the room, but my point is simple — both the underlying phenomena and the outcome are the same no matter what we name it, the room ends up warmer.
in the same way we can say that DLR warms the ocean or that it slows the cooling of the ocean, it doesn’t matter. The point is that the ocean is warmer with the DLR than without, much warmer. Our name for it doesn’t change the fact that it’s warmer with DLR.
As I said before, when common parlance conflates distinct processes, only confusion can result. Better to be more careful with words IMO.
Nor is it meaningful to say that DLR striking the surface can’t warm the bulk of the ocean. As Tim the Toolman agrees (I think), the bulk of the ocean ends up warmer with DLR than without … so what does “DLR can’t warm the bulk” mean when not just the surface but the bulk ocean undoubtedly ends up warmer with DLR than without DLR?
Tim agrees, as do I, that the presence of the radiative flux slows down the cooling of the ocean. Stephen Wylde thinks the magnitude of this effect is fixed by surface pressure – I think. I’ll be discussing that in person with him in a few weeks time.
I don’t think DLR striking the surface can heat the bulk of the ocean, and neither does Tim, for all the reasons we’ve rehearsed several times on this thread and many others.
LW Radiation only penetrates a few nm.
Conduction can’t go downwards because the surface is cooler than the subsurface.
Turbulent convection isn’t significant because if the eddies aren’t strong enough to pull down fingernail sized pieces of saturated toilet paper then they’re not strong enough to survive destructive interference beyond a few inches. Take it from someone who has designed centrifugal pumps.
Cheers
TB.
Willis Eschenbach says:
August 18, 2011 at 10:47 am
Perhaps that works with your friends, Roger, that you wave your hands and say that the dance of the photons is what keeps DLR from warming the ocean, and that the photons are dancing because of an invisible mist above the water … around here we need a bit more than that.
Hi Willis, the tone setting and hand waving you did earlier in this thread seemed to work for you. However I don’t see too many of the back slappers and me-toos left here defending the physically untenable. I’ll come to that.
Perhaps you think sea fogs appear out of thin air?
I think they happen when sub-visible water vapour already present in the air above the sea surface cools and condenses. You can prove this one for yourself in a kitchen experiment. A pan of water which has the heat under it reduced suddenly will get a mist of visible steam suddenly appear on its surface. This isn’t happeneing because more water is evaporated when the heat is reduced WIllis. It’s happeneing because the sub-visible water vapour molecules condense and agglomerate due to the reduction in available energy.
What is the second “distinct process” that the DLR is doing that I’m conflating with DLR hitting something and warming it?
The longwave flux keeps the air warmer than it would otherwise be by thermalising water vapour and co2. This reduces the temperature differential between the sea surface and the air. That slows down the cooling of the ocean. Not by very much, but is is a real physical effect.
TB-“I don’t think DLR striking the surface can heat the bulk of the ocean, and neither does Tim, for all the reasons we’ve rehearsed several times on this thread and many others.”
That’s because you refuse to see that when something “slows down the cooling of the ocean”, the bulk of the ocean ends up warmer. We call that “warming the ocean”, and yes, it occurs simply by slowing the cooling.
That is the effect of the physically distinct process outlined above. Thanks for agreeing that we are talking about ‘slowing the cooling’ rather than ‘heating’.
TB-“LW Radiation only penetrates a few nm.
Conduction can’t go downwards because the surface is cooler than the subsurface.”
You’re looking at this backwards. In a system in which the surface is maintained at a slightly lower temperature than the bulk … what happens if you forcibly warm the surface? Think it through all the way, Roger. The very surface warms … until it’s slightly warmer than the bulk … which then heats up slightly, until the surface is slightly cooler than the bulk, and the previous condition (cooler surface) is restored.
I think this is handwaving for which there is plenty of refuting observational evidence in the literature. It’s more imaginitive than your earlier effort though.
Unless your claim is that such a system can’t be heated from the top … but I don’t think that’s your claim.
On the rare occasions the air is warmer than the water, it can be heated from above to a very limited extent by conduction.
TB-“Turbulent convection isn’t significant because if the eddies aren’t strong enough to pull down fingernail sized pieces of saturated toilet paper then they’re not strong enough to survive destructive interference beyond a few inches. Take it from someone who has designed centrifugal pumps.”
Have you ever seen the ocean? There’s turbulence there that will pull down a swimmer, much less fingernail sized pieces of paper. Wind plus ocean equals turbulence that sinks ships, so I haven’t a clue what your claim means, or what designing pumps has to do with it.
I lived on a sea going boat I restored for seven years. I have done a lot of swimming in it, and I’ve never been sucked under in the open sea. The eddies you are talking about take place in tidal rips down channels between land masses. There’s a lot more open ocean than coastal places where such mayhem can occur. Ship sinking waves on the open sea do occur, but winds that strong and freak waves are rare. I specified the conditions of my experiment and they hold good for the majority of conditions short of breaking wave tops in the open sea. When designing the involute curve of a centrifugal pump casing, you match the velocity of the water flow to the radius it travels round to minimise cavitation and vorticity which forms eddies. This is because eddies interfere with each other and make the flow turbulent, reducing velocity, promoting wear and requiring more power to shift the fluid. I understand the way water moves under various kinds of impelling forces. Turbulent convection at the ocean surface in open water under non-white-top conditions is negligible in terms of forcing warmer packets of water down into cooler.
TB, because the ocean can only lose energy through the top, the top is always slightly cooler than the layer below.
What seems to have escaped you is that this setup, cooler water on top of warmer water, is inherently unstable because the cooler water is denser than the warmer, and it wants to sink, and does so. The cooler surface is kept in existence by water moving to the surface, cooling, sinking a mm or so, rewarming, rising to the surface, cooling, sinking a mm or so, and so on.
I agree that natural convection is continually taking place. It doesn’t help your contention that heat moves downwards from the surface though, because what you have just described is heat moving upwards.
So rather than being thermally isolated from the bulk below as you seem to be claiming, the cooler skin surface is constantly exchanging energy and water molecules with the bulk ocean below. And of course, because of that, any radiation absorbed by the skin surface affects the heat loss (and perforce the temperature) of the bulk of the upper ocean.
I haven’t claimed anything of the sort. Energy is constantly being exchanged, upwards. You are correct that radiation absorbed by the skin surface affects the heat loss, and in combination with the upward long wave radiation, the flux leads to a cooling of the surface by around 66-70W/m^2. However, there are other factors which also maintain the skin temperature and subsurface gradient which are larger in sum than radiation effects.
In other words, the DLR doesn’t need to penetrate to the depths in order to warm the depths.
It can’t penetrate to the depths and it can’t warm the depths through direct interaction with the ocean any more than negligibly. As part of the long wave flux in the air, a change in the amount of DLR relative to ULR can cause the ocean to cool marginally more slowly, though the size of the effect will be small compared to convective and albedo changing processes.
Cheers
TB
This topic seems to go round and around like a whirligig! It is obvious that radiative energy exchange between ocean and atmosphere is a complex process which has been empirically modelled, but without a real understanding of the interlocking processes involved regarding the real world macro-system.
Interesting and surprising things happen at boundaries and it is just as import to understand what happens in the few cm of air immediately above the oceans surface as to what happens in the <1mm below the surface. Due to the high humidity above the surface of the water, I suspect very little DWIR even gets to the surface, and most ends up being shuffled out into space by the heat of evaporation. But who knows???
Dave Springer says:
August 16, 2011 at 6:15 pm
Matt G says:
August 16, 2011 at 4:53 pm
tallbloke says:
August 16, 2011 at 4:14 pm
NASA have stopped using the K-T energy budget cartoon on their website which shows the separate LW radiation components and replaced it with this one which only shows the net flow:
Excellent. Actual net surface energy from NASA. A clear picture unsullied by obfuscatory unnecessary opposing flows that cancel out.
I culled it down to global means to make a point:
Average net shortwave radiation at the Earth’s surface: January 1984-1991.
Global mean = 162 W/m2
Average net longwave radiation at the Earth’s surface: January 1984-1991.
Global mean = -48 W/m2
Average net radiation at the Earth’s surface: January 1984-1991.
Global mean = 114 W/m2
So we see here in simple terms that at the surface, which is where we live and why I eschew obfuscatory Top of Atmosphere budget, we have at the end of the day (or rather end of the decade) a net radiative flow of 114 W/m2.
This 114 W/m2 is the amount of energy that doesn’t leave the surface radiatively. Compare this to 48 W/m2 which is the amount of energy that does leave the surface radiatively. LWIR emission only accounts for 48/114 or 42% of all radiative heat loss from the surface, land and ocean combined. For the ocean-only the radiative loss is only 25% (see my previous link to ocean heat budget).
What this means is that the lion’s share of heat loss is not via radiation and that’s especially true over the ocean. Where radiative loss is not a large factor neither can greenhouse gases be a large factor because radiation is only mechanism by which GHGs do their GHG thing.
Given the ocean is 70% of the surface, for the combined total radiative heat loss to reach 42% the land masses must be very much dominated by radiative loss. But over the ocean, not much. It’s mostly about latent heat loss over the ocean.
This is just more in the way of empirical evidence (not toy models or thought experiments with heat lamps and pans of water) that the GHG effect is predominantly a land based phenomenon.
QED
Peace. Out.
The ‘usual’ tale about how certain frequencies of upward LWR are absorbed by CO2 leaves me cold. The tale always focuses on upward IR radiation without mentioning any potential thermal effects associated with the much greater amplitude downward solar IR component.
And the Kiehl-Trenberth0 ‘Energy balance’ graphic in IPCC AR4 makes a mockery of the ‘greenhouse’ tale with its claim that ‘back radiation’ is twice as strong as solar radiation. What precautions were recommended by the IPCC to avoid members of the public suffering ‘Back radiation burn’ during the ‘back radiation’ season? (tongue in cheek)
TB:
Seems to me we can lay this back radiation issue to rest one way or the other simply by watching what happens to SSTs over the next ten years or so. If the oceans are heated entirely by the sun we should now begin to see a decrease in global SST related to the recent decrease in the level of sunspot activity, all other things being equal. And if we don’t we can assume either that back radiation is somehow getting into the oceans or that all other things aren’t equal.
My official projection of 21st century SST anomalies can be used as a model 🙂
https://tallbloke.files.wordpress.com/2011/05/ra-fig6.png?w=600&h=434
[…] Hitherto, theorists have got around this problem by denying it exists, or just ignoring it. In a discussion on this issue, Willis tried to get around it by saying that wind ruffling the water surface will mix the DLR […]