Guest Post by Willis Eschenbach
To continue my investigations utilizing the CERES satellite dataset of top of atmosphere radiation, here is a set of curious graphs. The first one is the outgoing (upwelling) longwave radiation at the top of the atmosphere (TOA) versus the sea surface temperature, for the northern hemisphere, at the times of the solstices and equinoxes.
Figure 1. Northern Hemisphere TOA outgoing longwave, versus sea surface temperature. Colors represent latitudes, as follows: dark blue, 10°; red 30°; yellow 50°; sky blue 70°. Vertical dashed line is at 30.75°C. Horizontal dashed line is at 300 W/m2. Black solid line shows the surface upwelling longwave radiation (calculated at emissivity = 0.95). Click to enlarge.
I find this graph both interesting and puzzling.
The first puzzle to me is, why is outgoing radiation in July about 230-250 W/m2 from the pole to the Equator? I mean, the upwelling radiation from the surface (solid black line) increases by 50% from the coldest to the warmest areas … but the upwelling longwave is all about the same regardless of the sea surface temperature. How bizarre!
The second puzzle is that there seems to be a fairly hard limit of about 300 W/m2 of TOA upwelling LW. Not only that, but it doesn’t vary much month to month.
The third puzzle is that even up in the Arctic regions, there’s little seasonal change in the upwelling LW. It only swings about 30 W/m2 at the most variable point, and less as you move away from the poles.
Now, what I think is happening at the warmest temperatures is the same thing that the TOA reflected solar showed in my last post—a significant increase in clouds. Let me explain why more clouds means less upwelling longwave radiation. Remember that this is upwelling longwave radiation. Suppose we have some amount X of upwelling radiation coming from the ground. If we interpose a layer of cloud between the surface and the TOA, the cloud will absorb that upwelling LW radiation, and then re-radiate it, half upwards and half downwards. This reduces the amount of upwelling longwave at the TOA, as we see happening at the warm end of the scale above.
Here is the same analysis, but this time for the southern hemisphere.
Figure 2. Southern Hemisphere TOA outgoing longwave, versus sea surface temperature. Colors represent latitudes, as follows: dark blue, 10°; red 30°; yellow 50°; sky blue 70°. Vertical dashed line is at 30.75°C. Horizontal dashed line is at 300 W/m2. Black solid line shows the surface upwelling longwave radiation (calculated at emissivity = 0.95). Click to enlarge.
Want to know what is surprising to me about the southern hemisphere?
I’m surprised at how little the TOA upwelling longwave changes from season to season. The sun comes and goes … but the southern hemisphere upwelling LW is largely unaffected. Every season of the year it’s about the same, 200 W/m2 around the icy antarctic, rising to 300 W/m2 at about 28°C, and then dropping from there. What’s up with that?
My goodness, the amount there is to learn about this incredibly complex system has no end, I can only shake my head in awe …
w.
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Willis … interesting that you’d bring this up … I”ve been reading the crap out of this very topic because, it is evident from reading a lot of literature that OLR at the TOA is solely depending on the cumulative LW radiation being emitted, which = LW(SST) + LW (land) + LW (Atmosphere), where the contribution from the atmosphere is Total LW (atmosphere)-LW from the atmosphere that was absorbed from the ocean or land [ie., greenhouse effect]. As such, not all SW radiation absorbed by the ocean is going to be immediately available for the temperature equation. The ocean works kinda like a capacitor. No suprise .. EVERY Temp metric follows the ocean SST. Quite simply put, the primary driver of our atmospheric temperature is not CO2, but rather the ocean SST. .. it is NUMERO UNO.
The temperature equation needs to be changed [IMO] from such that S(1-a) is replaced by the above LW contributions. … LW(SST) + LW (land) + LW (Atmosphere),
The literature supports your pont regarding the drop off in OLR above a certain point. From the reading of the literature that I”ve seen, increased clouds is a significant damper on ocean OLR. 1) it is blocking short wave .. and 2) it is contributing to downwelling LR, thus decreaseing net ocean OLR.. .. and 3) as you said, aborbing upwelling LW from the ocean itself.
This same phenomenon is also the explanation for why you don’t see a linear relationship between OLR at the Pole vs the Equator. Clouds increase as you move towards the equator, thus the same muting effect that you noted at 30C surface temp is operating throughout the transition of latiitude.
Due to simplified diagrams it is sometimes thought that outgoing LW radiation is a vertical process. It is not, the radiation is constantly absorbed and re-emitted, thermalized and de-thermalized. The process is more like diffusion. As such, the radiation measured at the equator could have originated at one of the poles. I think this is one of the reasons for the relative flatness of the line. That along with the fact that most of the radiation comes from higher altitudes. This works in conjunction with the heat flow from general circulation but works constantly to try and even out the temperature of the atmosphere, thus stabilizing the structure.
In addition, the frequencies start to “blur” as part of the diffusion process. That is, the energy radiated from the surface in bands that CO2 absorb can be changed into bands absorbed by water vapor, clouds, etc. … and vice versa. While more energy may be absorbed with some added CO2, the added CO2 also assists in diffusing the energy already absorbed. IOW, the process is made more efficient and the result is not so much a warmer atmosphere but a more stable atmosphere.
Good comments from Richard M
If someone looks at the IR of a hurricane the most striking thing is how cold and high it is. The other thing they may know is that the lowest pressure comes with the highest column of air. The center of a hurricane rises miles into the stratosphere.
Humid air is less dense than dry air and contains more heat for a given temperature and volume. A hurricane (water vapor) transports warm humid air from the surface high into the atmosphere but the expansion of the air translates into very cold air, hence a lower IR TOA emission.
An atmosphere in equilibrium is Isothermal. GHG’s create a lapse rate and water vapor erases the lapse rate.
You want to know what’s really amazing?
Over three years ago here on WUWT, a proposal was posted here about using shipping containers as emergency housing in earthquake-devastated Haiti, which is also known for being frequently tropical storm-devastated.
http://wattsupwiththat.com/2010/01/20/just-crazy-enough-to-work-shipping-containers-for-emergency-shelters-in-haiti/
Today it is reported shipping containers are to be used for “emergency housing” in London, where there is a chronic shortage of cheap rents. Come with full plumbing, ‘leccy, bi-directional heat pumps, burners for cooking. Stackable housing, deploy where needed. Imagine these replacing FEMA trailers in the US.
http://www.dailymail.co.uk/news/article-2450762/Shipping-containers-rented-London-homes.html
I’m posting this here as Mr. Eschenbach has been known to appreciate innovative solutions using minimal resources.
I feel like I must not be understanding something. How can so much Long Wave radiation be escaping high latitudes in December, when there is hardly any sunshine? Is it transported north by Hadley, Ferrel and Polar cells? Is it latent heat from oceans that are relatively warmer than the air, and whose evaporation creates huge North Atlantic and North Pacific gales? (I’ve read something like 23% of outgoing long wave radiation is via latent heat exchanges.)
One final question, before I halt my public display of ignorance. Is this CERES satellite able to differentiate between the origins of the heat it is sensing, or does it just measure heat in general?
(I’m most interested in the difference between heat lost by the Arctic Sea when it is covered by ice, versus when it is open water. Is the CERES satellite capable of measuring something like that?)
Willis, I need a clarification here. When you say TOA upwelling, do you mean radiation that is emitted from the top of the atmosphere only, or all the radiation emitted as measured at the top of the atmosphere?
Thanks.
I am having difficulties posting a comment. An add appears over the e-mail and username and blocks the access. I am posting this comment from my wife’s computer. Is anyone else having this problem?
Willis, considering the data set that you are using, can you use this data and the cyclic variation of carbon dioxide in the atmosphere to calculate the sensitivity of the climate to carbon dioxide concentrations in the atmosphere?
John,
I’ve checked the sensitvity of OLR by regions and find it is very sensitivity to moisture content (water, gas, or ice) but not to CO2. http://www.kidswincom.net/CO2OLR.pdf.
Roy Spencer says :
“Willis, if you would read up on what we already know about this stuff, you would not be so perplexed.”
Claude Harvey says :
“Don’t listen to Roy, Willis. Discovering stuff on your own is what makes you get up in the morning. It also makes you a much more interesting fellow than Joyless Roy.”
I agree with both comments, but I tend to lean towards Joyless Roy on this topic.
Roy Spencer says:
October 9, 2013 at 4:23 am
Dr. Roy, I listed three, well actually four puzzling things to me:
The first is that despite the ocean being much colder near the Arctic in July than it is at the Equator, the TOA upwelling longwave radiation (ULR) is nearly constant from Arctic to Equator. Why doesn’t the ULR drop with the surface temperature as it does during other months?
The second is that nowhere over the ocean do we see more than about 300 W/m2 of TOA upwelling LW radiation. Why the limit?
The third is that from Arctic summer to Arctic winter, which means from full sun to no sun at all, the ULR in the northernmost and coldest oceans varies by only about 20 W/m2. Why so little?
The fourth is that unlike in the northern hemisphere, in the southern hemisphere the upwelling LW changes very little from month to month. Why the difference from the NH, which does vary on a monthly basis?
Perhaps you could send us links to the previous studies that you say explain all of these questions. That would be more useful than a drive-by posting … you keep saying that all of this is known and well-studied.
So if you’d be so kind as to give us the links to the relevant studies, that would be much appreciated.
All the best,
w.
sophocles says:
October 9, 2013 at 12:59 am
The actual split of the ocean is Southern Hemisphere, 57% and Northern, 43%. So while there is an imbalance, it’s not that large.
While that is assuredly true … why wouldn’t that circulation vary from the Antarctic summer to their winter?
They help, but I don’t think they explain the overall thermal stability of the SH as compared to the NH …
w.
Ahh. The science is settled. Again.
(Oh. OK. Sarc. Did anyone guess?)
Well done Willis! More queries, more areas where it is clear that, after all, not all the science is fully settled.
I don’t have anything like the expertise to otherwise comment, but do appreciate my eyes being opened on this.
Auto
Willis: I mean, the upwelling radiation from the surface (solid black line) increases by 50% from the coldest to the warmest areas
that’s calculated from a model like Stephan-Boltzman, or measured? And how accurate is the model for open water?
Your empirical finding is intriguing no matter what the answers to my questions? One would expect the upper troposphere to be warming more at those higher surface tempeeratures, or else the upward radiation maintaining the water vapor in its vapor state longer, or both. (probably other possibilities I have not thought of.)
Oceans & seas make up around 81% of the SH, while only about 61% of the NH is covered by seawater, IIRC.
Roy Spencer: Willis, if you would read up on what we already know about this stuff, you would not be so perplexed.
With respect, could you provide us a few bullet points describing what here was already known, and the references? This is a good place whenever you want to provide us denizens with information that we have not come across in our other searches. I follow most links to information, and others do as well.
Edim says:
October 9, 2013 at 1:07 am
I do so enjoy a man who shows up with actual numbers, thanks, Edim.
Global average TOA upwelling longwave in the CERES 10-year dataset is 239.6 W/m2
Some 40 W/m2 is known to go through the “atmospheric window”. That’s about 16%. About 26 W/m2 (11%) comes from the clouds. The rest (73%) comes from the atmosphere.
Mmmm … not so. The sources of energy in the atmosphere are:
Absorbed from sunlight: 68 W/m2
Sensible heat (conduction): 22 W/m2
Latent heat (evapo-transpiration): 76 W/m2
Radiation: 340 W/m2
The non-radiative gains from the surface (sensible plus latent heat) only total about 100 W/m2. This is only about 20% of the heat gained by the atmosphere.
You might enjoy my reworking of the Kiehl/Trenberth global energy budget. Unlike theirs … mine balances.
w.
The puzzling aspects of the latitudinal variation of OLWR are most likely the consequence of the homogenizing effect of entropy. At altitudes from which such radiation escapes to space, there is little diurnal and seasonal variation as well. Such strong homogenization involves much poleward advection of heat and turbulent mixing, not just the vertical transport commonly portrayed.
Willis,
Edim is correct, in terms of net flux in and out, most of the energy being radiated from the top of the Hadley, Ferrel and Polar tropospheric circulation cells as LWIR was acquired by surface conduction and the release of latent heat.
This net flux diagram is slightly less of a travesty than Trenberths effort –
http://upload.wikimedia.org/wikipedia/commons/5/50/Breakdown_of_the_incoming_solar_energy.svg
Radiative gases being able to emit LWIR from the top of the atmosphere plays a critical role in tropospheric convective circulation, allowing air masses entrained in the Hadley, Ferrel and Polar cells to lose buoyancy and subside.
Altering the concentration of these gases in our atmosphere alters the speed of tropospheric convective circulation (there would be no circulation without them), and thereby the speed of mechanical energy transport away from the surface. Mechanical energy transport includes the movement of energy from latent heat and surface conduction to the upper atmosphere.
Without radiative gases, tropospheric vertical circulation would stall and the atmosphere would trend isothermal by gas conduction. (Dr. Spencer got this right). The surface would experience severe temperature variations but only over land. (Dr. Spencer got this 29% right). The resultant isothermal temperature would be set by surface Tmax. ( Dr. spencer got this wrong and used Tav, and a Tav too low at that). Poorly radiative gases stagnated at altitude would then super heat, just as in the thermosphere, and boil off into space. (Dr. Spencer did not consider this). Our atmosphere is therefore cooler due to radiative gases.
There is a slight radiative green house effect on earth, most notable over land at night, but the net effect of radiative gases in our atmosphere is atmospheric cooling at all concentrations above 0.0ppm.
Please do not fall in the the old Trenberth energy budget trap to calculate gross heat transfer for radiation only.
Do as every engineer do, calculate NET heat transfer for atmosphere by radiation as for all other way of heat transfer and You find the atmosphere NET heating are only 339-321 +13 = 31 W/m2 by radiation.
The reason for this? GHG efficiently block heat transfer by radiation. Call it back radiation or whatever but it is still only 31W/m2 by radiation. Net. Ask any engineer.
22W/m2 by sensible heat, 76W/m2 by latent heat and 31 W/m2 by radiation and 68 W/m2 direct by sun. The atmosphere is heated only by 31/197 or about 16% by LW radiation.
When You use this net radiation values will You also understand why it is so important for IPCC to use big number in radiation to fool people to get the impression that the atmosphere is heated by LW from ground. It is not. And it is because of the efficiency of GHG.
There is Your answer why surface temperatures do not reflect in outgoing LW at TOA.
The atmosphere is cooled 100% or with 237 W/m2 by radiation. From my view is the atmosphere radiative heat balance LW out 237 W/m2 and 31 W/m2 in. Net radiative heat transfer for the atmosphere are -206 W/m2 .
The atmosphere is cooled by GHG from a heat transfer perspective.
Konrad 1:57pm: “This net flux diagram…”
The diagram you link is in units of power.
“Without radiative gases…”
Refer to the chart of earth’s PW of power in and power out that you link. If infrared active gas ppm in earth’s atm. tends toward zero, then what values would the 33 and 26 PW power “absorbed by atmosphere” (~orange arrows) tend toward in that chart?
“You might enjoy my reworking of the Kiehl/Trenberth global energy budget. Unlike theirs … mine balances.”
How much sunlight is diffused- it gets to surface but not in direct path?
coldlynx says:
October 9, 2013 at 2:11 pm
……..
The atmosphere is cooled by GHG from a heat transfer perspective.
======================
Interesting. I have reasoned with this frequently over the past couple of years. Never commented with regards to the heat transfer from non-radiating gas to that of a radiating gas. You are the first to address this and matches my line of reasoning. Good to see someone put numerical values to it. I hope to see this discussed more in depth.
Robert Brown: “My secondary goal in this is to look at fluctuation-dissipation in a trivial physical model. One obvious flaw in the GCMs is that they individually fluctuate around their current smoothed GASTA prediction at an amplitude that is nearly twice as great as the actual obvserved amplitude of fluctuation, and fluctuate more more regularly than the actual climate, and have far too steep a rate of fluctuation growth compared to the regular climate. ”
English, please, Dr. Brown. Or maybe math. Either one (but preferably both, one describing the other) will do. Please understand that, although many–perhaps most–of us are laymen, a lot probably did fulfill a college math requirement, Undoubtedly English, too. Jargon, not so much.
If your goal was to frighten the natives with the abstruse nomenclature, you probably achieved it with some subset of the readership. If it was to inform, I have my doubts.
Maybe a little off topic but everyone else is riding their hobby-horse
The whole concept that absorbed/emitted radiation
changes the temperature of a molecule is flawed. I am
specifically refering to absorption lines. Photons are
not particles of heat. Photons are energy particles. In
our day to day life we connect heat to energy but in the
case of molecules the lines indicate a mechanical change
to the structure of the molecule, ie stretching,
rotating, shifting of electrons etc.. The photon cannot
both ‘heat’ the molecule and ‘twist’ it at the same
time.
So, in fact, absorption actually reduces the amount of
heat that is potentially available. Yes, I know, it
eventually dissipates back into the system by various
means. So what? It was taken out of the system and was
then eventually returned. No net gain or loss. There
might be a delay in energy transfer in the time scale of
milliseconds but that doesn’t matter. The atmosphere is
like an energy conveyer belt. Energy comes in at one end
and leaves at the other to space. If there is an
increase or decrease in the energy the belt adjusts.
Don’t believe me? Look at electron drift in conductors.
The electron you pump into the system from the power
source is not the same electron that does the work. The
energy from the sun that we receive daily was created
millions of years ago in the centre of the sun.
You don’t believe that energy can be absorbed without
changing temperature? If no, then explain latent heat to
me. Water at 100 deg C and steam at 100 deg C.