Guest Post by Willis Eschenbach
There is a more global restatement of Murphy’s Law which says “Nature always sides with the hidden flaw”. Parasitic losses are an example of that law at work.
In any heat engine, either natural or manmade, there are what are called “parasitic losses”. These are losses that tend to reduce the temperature differentials in the heat engine, and thus reduce the overall efficiency of the engine. In general, as a percentage parasitic losses increase rapidly with ∆T, the temperature differences in the engine. In the climate system, two main parasitic losses are the losses from the surface to the atmosphere by way of conduction and convection (sensible heat), and the losses from surface to atmosphere by way of evaporation and transpiration (latent heat). Both of these parasitic losses act to reduce the surface temperature with respect to the overlying atmosphere, by simultaneously cooling the surface and warming the atmosphere … nature siding with the hidden flaw to reduce the overall system efficiency. So I decided to see what the CERES data says about parasitic losses. Figure 1 shows the parasitic losses (the sum of sensible and latent heat losses), as a percentage of the total surface input (downwelling longwave plus shortwave).
Figure 1. Parasitic losses (latent and sensible heat loss) from the surface to the atmosphere. Percentage of parasitic loss is calculated as the sum of sensible and latent loss, divided by the total surface input (downwelling shortwave plus downwelling longwave).
I was most interested in how much the parasitic loss changes when the total surface input increases. Figures 2 to 4 shows that situation:
Figures 2-4. Scatterplots, parasitic loss in watts per square metre (W/m2) versus total surface input (W/m2). Parasitic loss is loss as sensible and latent heat. Gold line shows the loess smooth of the data. Red dots show land gridcells, which are one degree square (1°x1°) in size. Blue dots show ocean gridcells.
I was very encouraged by finding this result. I’ve written before about how at the warm end of the spectrum, parasitic losses would increase to the point where most of each new additional watt striking the surface would be lost as sensible and latent heat, and that little of it would remain to warm the surface. These graphs bear that out entirely. Here’s why.
The slope of the gold line above is the rate of increase in parasitic loss for each additional degree of warming. As you can see, the slope of the line increases from left to right, although the rate of increase goes up and down.
In order to understand the changes, I took the slope (change in parasitic loss divided by the corresponding change in surface input) at each point along the length of the gold line for both the land and the ocean separately. Figure 5 shows that result.
Figure 5. Change in parasitic loss (in W/m2) for each additional W/m2 of surface input. “Wobbles”, the looped parts in the two graphed lines reflect subtle changes in the loess smooth, and can be ignored.
Now, what are we looking at here? Well, this is how the parasitic loss changes as more and more energy is input to the surface. Where there is little surface input, the loss is low. In fact, at the South Pole the situation is reversed, and the net flow of energy is from the atmosphere to the surface. This is the result of huge amounts of energy being imported from the tropics.
The key point, however, is that as we add more and more energy to a given gridcell the amount of parasitic losses rises, in perfect accordance with nature siding with the hidden flaw. And at the right hand end of the scale, the warmest end, for every additional watt that is added, you lose a watt …
Is this relationship shown in Figure 5 entirely accurate? Of course not, the vagaries of the smoothing process guarantee that it isn’t a precise measure.
But it clearly establishes what I’ve been saying for a while, which is that parasitic loss is a function of temperature, and that at the top end of the scale, the marginal losses are quite large, close to 100%.
Now, as you can see, nowhere is the parasitic loss more than about 30% … but the important finding is that the marginal loss, the loss due to each additional watt of energy gain, is around 100% at the warm end of the planet. Here is the parasitic loss for the planet as a whole versus total surface input as shown in Figure 2:
Figure 6. Change in parasitic loss (in W/m2) for each additional W/m2 of surface input, as in Figure 5, but for the planet as a whole.Change in parasitic loss (in W/m2) for each additional W/m2 of surface input. “Wobbles”, the looped parts in the two graphed lines reflect subtle changes in the loess smooth, and can be ignored.
Note also that across the main part of the range, which is to say in most of the planet except the tropics and poles, about half of each additional watt of energy increase doesn’t warm the surface … it simply goes into parasitic loss that cools the surface and warms the atmosphere.
Best to all,
w.
PS—If you disagree with what I’ve said please quote my words. That lets all of us know just exactly what you disagree with …
It appears people are talking around each other. Willis defined his view of parasitic losses. There is nothing wrong with his calculations based on his definitions. I think most of the objections come from disagreements with his definitions. Nothing wrong with that either but that doesn’t mean his calculations are wrong. They are just different.
Willis gets a % number based on total downwelling LWIR + surface SW (18%). One could also compute a % number based only on surface SW. The number would be substantially different (~65%). To me neither number is right or wrong unless it is used inappropriately.
Edim says:
March 27, 2014 at 1:32 am
Two comments on that, Edim.
First, why do you think people call something “INPUT”? Because it is the total of what is going INTO something else, and so of course it ignores what is going OUT OF the something else in question.
For example, the INPUT to a car is gasoline, that is to say petrol. It is not petrol plus some of the exhaust. Exhaust is OUTPUT from a car, fuel is INPUT. Surely you don’t claim that the input to the car is petrol plus exhaust, do you?
As a result, the idea that something called “surface input” should measure anything but the input to the surface makes no sense.
My other point goes deeper, which is that if you want to engage in a discussion, you need to use the terminology of that discussion. If they are talking Russian, it’s useless to insist that the right way to go about it is to speak French.
Similarly, when we are talking about surface input (curiously defined here as what goes INTO the surface, it is useless to insist that the right way to do it is to say that “surface input” means all of the input plus some but not all of the output. All that happens when you insist on speaking French is that you get left out of the conversation …
Doesn’t mean you’re wrong, French may indeed be better … but not when everyone’s speaking Russian.
w.
James Rollins says:
March 27, 2014 at 2:40 am
james, I never said that. You made up that fake quote root and branch.
Putting that load of bollocks out and claiming it is a direct quotation of my words is an extremely dishonest and dishonorable tactic.
w.
James Rollins says:
March 27, 2014 at 3:18 am
Actually … there is a fundamental difference. It is in the very thing we are discussing, the ratio between radiation and conduction/convection.
Suppose we have a solid lump of aluminum ore. It loses little by convection/conduction, and mostly by radiation.
Suppose we replace it with a motorcycle head, same weight of aluminum, with all kinds of cooling fins.
The motorcycle head will have a different ratio of radiation and conduction/convection, since much more of its heat will be lost through conduction/convection due to two factors: physical shape and heat conduction.
The motorcycle head has fins, and is made of a metal which rapidly conducts heat.
The lump of ore has no fins, and is made of ore which is a much poorer conductor of heat.
If you think the two of those, the natural material and what we shape it into, have the same ratio of heat loss (radiation vs conduction/convection), I fear I can’t help you.
w.
rgb, I think it’s misleading to count only one direction (downelling) of the LW radiation. The surface input is either the absorbed solar only (SW) or the net radiation (SW + LW), which is also acceptable. SW + LW(downwelling) as a surface input makes no sense and it’s misleading IMO.
I have to keep this short — quizzes to write, class to teach — but it is a simple matter of fact that treating the surface as SW + LW downwelling DOES make PERFECT sense — in a single layer model such as the one Grant Petty walks you through in A First Course in Atmospheric Radiation. I promise — fact, not opinion, as proven by the fact that it is easy to turn the concept into a quantitative model. One cannot turn senseless ideas into quantitative models.
Nowhere did I or does the theory assert that only one direction of LW radiation is treated — this is your imagination, not the actual theories. Again I refer to Petty, where he treats absorption and emission as symmetric processes (as they must be according to Kirchoff’s Law!) with the same coefficient. In a single layer model, the atmospheric layer absorbs some fraction of upwelling surface radiation and reradiates it both up and down. The up component is part of the energy balance loss that keeps the atmospheric layer itself in detailed balance. The down component is pure gain for the surface, added to the SW (that makes it through the atmosphere) gain. This total gain has to be balanced by the LW upwelling loss in steady state (plus, as Willis points out, a much less well defined loss associated with conductivity and latent heat transfer — it isn’t only about the radiation).
None of the models are senseless (at least, not deliberately so as anybody can make an error) — at worst they are incomplete, oversimplified, and/or just lead to incorrect answers for the processes they attempt to model.
Also, I do not understand what the difference is between SW+LW as a surface input and SW+LW (downwelling) in your statement above. Surface inputs are by definition going to be downwelling (except for trivial amount of e.g. geothermal heat). Surfaces losses are going to be upwelling. Both of these might as well be written as SW(downwelling) + LW(downwelling) or “total radiation(downwelling)” — there is no difference between the four descriptions except in how you partition downwelling radiation by wavelength. So I cannot understand your objection quite aside from your mistake in calling any of these partitionings senseless.
rgb
Kristian says:
March 27, 2014 at 7:37 am
Glad you asked. The answer is twofold.
1. We can’t harvest thermal IR the way that we do solar energy (photocells). While it assuredly contains energy, the thermal IR simply doesn’t have enough energy to kick an electron out of its orbit … so no photoelectric harvesting is possible.
2. When photoelectric is ruled out, that only leaves a heat engine to harvest the energy. The problem with that is that a heat engine works off of ∆T, a temperature difference. As a result, we’d need a colder place to exhaust the waste heat to … and the incoming heat is only at about 0°C or so on average. The atmosphere straight up a few miles is generally the coldest place within a few miles, by a long ways … so we have no place to exhaust the waste heat.
So the answer to your question, why doesn’t humanity try to harvest the back radiation, is that we haven’t figured out a single way to do that, or even an approach that might possibly work.
Doesn’t mean it doesn’t exist, however, that’s nonsense … but like many kinds of energy, we haven’t figured out any way to utilize it.
Hogwash. Absolute hogwash.
The downwelling IR has indeed been MEASURED, to use your capital letters, thousands and thousands of times, all over the planet. We have special instruments to measure it. We have people whose job is to measure it. We have scientists who’ve spent their lifetimes measuring downwelling IR. Have you been asleep for the last century? You can measure the downwelling IR with a cheap IR thermometer, for heaven’s sake.
Your bizarre claim that we haven’t ever measured the downwelling IR is a perfect example of your terribly flawed understanding of the situation, Kristian … do a google search and you find hundreds of articles describing what you say doesn’t exist, their measurements of downwelling IR.
Of course you might not have noticed them, because often they have deceptive titles like Measurements of Downwelling Infrared Irradiance … read that, and come back and tell us what you found out.
w.
Dan Hughes says:
March 27, 2014 at 8:38 am
Dan, my thanks, and good to hear from you as always. I am aware of (although not fully conversant with) Bejan’s later work, but I usually use the earlier one because it’s more of an introduction to the subject.
All the best,
w.
Thank you Willis for a new installment in what looks to be developing into a comprehensive text on real climate science. Looking at the figs 5 and 6 blue traces and imagining a transition from night to day in a single grid cell suggests that losses at the low input end for the oceans has a dominant conduction component into the the atmosphere, the mid range a conduction-convection dominating transitional range followed at the higher input by a dominant latent heat range particularly aided by a jump in the convection component since higher water vapour reduces atmospheric density at the surface.
Willis, don’t you understand that when you read a mercury “thermometer”, you aren’t measuring temperature. You are simply measuring the height of a column of mercury. Then you are relying on a mathematical model of the column in which the mercury resides, and another mathematical model of the properties of mercury, to calculate the supposed temperature.
Need I say ?
The last line was supposed to be:
Need I say “/sarc”?
rgbatduke says, March 27, 2014 at 11:07 am:
The point here is that you let the postulated ‘downwelling LW’ component from the cooler atmosphere alone (not in collaboration with other fluxes) raise the temperature of the warmer surface (increase its internal energy) directly (not indirectly) and in absolute terms (not in relative terms). Such an energy flow with such a result is defined in physics as HEAT (or work). And heat in nature does not and cannot go from cold to hot. You seem completely impervious to this simple demonstration that there is clearly something fundamentally wrong (and/or misunderstood) with the traditional ‘Prevost energy exchange principle’.
Compare an earth with an atmosphere without so-called GHGs (but with albedo unchanged) with an earth with an atmosphere with so-called GHGs.
In the first situation the global surface absorbs an average solar flux of 239 W/m^2 and then, according to you, emits an equal flux directly to space to balance it. This according to you gives a mean surface temperature of 255K.
In the second situation the global surface absorbs an average solar flux of 165 W/m^2 which alone would’ve set the mean temperature to 232K. So how do we get to 288K? What’s changed? Is the solar increased? No. Is the resulting outgoing radiative flux from the surface reduced? No.
We ADD an extra energy flux, from the cooler atmosphere. That’s the (only) difference. And by that go from 232K to 288K. Your added 345 W/m^2 from the atmosphere to the surface in no way reduces the outgoing flux. It INCREASES it. Your 398 W/m^2 going out could not reach that level without the added flux from the atmosphere: 165+345 (510) = 112*+398 (510) (*convective losses).
So you let the 165+345 heat the surface FIRST (well, actually after strangely having subtracted the convective losses even before this: (165+345) – 112 = 398) and THEN only is the surface allowed to cool.
So in reality what you do is treat the 345 flux as a second HEAT flux to the surface, because it (and ONLY it) increases the internal energy of the surface (and thus the outgoing flux) and thereby its temperature … directly and in absolute terms. You will of course never admit to this, but that is what you DO (if not saying). Worse than that even, what you ultimately end up claiming is that any object can raise its OWN temperature purely by absorbing its OWN previously thermally emitted and then recycled radiative energy loss.
This is impossible in nature. In fact, it’s ridiculous. The laws of thermodynamics simply do not allow it.
The only reasonable (and reality oriented) way to set up the energy (heat) budget for the earth’s surface is like this:
ENERGY IN: 165 W/m^2 = ENERGY OUT: 53 [398-345] W/m^2 + 112 W/m^2
Edim is completely correct. Your postulated DWLWIR flux is a component of the surface’s energy OUTPUT, not INPUT.
Curt says, March 27, 2014 at 1:01 pm:
“Willis, don’t you understand that when you read a mercury “thermometer”, you aren’t measuring temperature. You are simply measuring the height of a column of mercury. Then you are relying on a mathematical model of the column in which the mercury resides, and another mathematical model of the properties of mercury, to calculate the supposed temperature.”
*Sigh*
You’re just displaying your utter lack of understanding, Curt.
What you describe above is equivalent to the change in the voltage in a pyrgeometer sensor detecting a ‘heat’ flux. The physical conversion is direct and firsthand: reading > conversion. Same with a speedometer.
The equivalent between stating that a 400 W/m^2 upward component is ‘measured’ and the thermometer would be if, AFTER you’ve observed the height of the mercury column, you applied a formula to claim that the temperature shown in reality is made up of a cold component and a hot component, as if the air in contact with the thermometer contained a volume at 280K and another one at 300K and therefore what you read off the column is actually a ‘net’ temperature of 290K.
I don’t expect you to understand the difference, Curt, but most likely other readers will.
Willis
in the link you provide claiming “proof of 400 wm sq”
the graph showing nightly readings
on site at your claimed proof it IS
measured at 400
it says clearly on Figure 3,
“Figure 3 Time series of downwelling infrared irradiance
for May 21, 2007. A clear sky was present from
midnight-midnight local time.
350 – 353 Watts/Sq. Meter.
I don’t know how important it is to the argument you’re having with the other man but the fact is
your link clearly disproves what you said at least in the instance of the study you provide
Willis Eschenbach says, March 27, 2014 at 11:20 am:
“Of course you might not have noticed them, because often they have deceptive titles like Measurements of Downwelling Infrared Irradiance … read that, and come back and tell us what you found out.”
Yes, and here is HOW it’s ‘measured’, Willis:
http://en.wikipedia.org/wiki/Pyrgeometer#Measurement_of_long_wave_downward_radiation
http://tallbloke.wordpress.com/2013/04/26/pyrgeometers-untangled/
You’ve been shown this several times before and you just continue to close your eyes. Your pigheadedness on this particular subject is what’s bizarre, Willis.
Wilis obviously it’s easy to check on your claim of 4/5ths loss via radiation from natural materials and it’s simply not coming up true. In spite of the fact that you claim natural material emits 4/5ths of it’s energy via radiation I checked the ratios for stone and everywhere the heating and cooling industry claim convection and conduction are primary removal means for energy when stone’s used.
Your claim is simply not within the realm of even the possible Willis
much less the probable.
If you expect to talk science with people Willis what you say had better meet with the ”that sounds like what I know to be true” across a wide swath of fields and one of the largest that your claim flies into the face of is everything mankind ever built or builds.
Everyone remembers being taught some thermodynamics.
Nobody remembers being taught radiant loss predominates in nature or we’d all agree it sounds right: if it were different your friends would be in here with every single link from every single building insulation site describing how all structures radiate, predominately;
but they don’t; because the fact is the vast majority of structures made by man cool primarily, convectively/conductively.
Everything you claim is propped up on tenuous arguments demanding everyone reading what you say utterly disregard the entire history of human endeavor keeping heat in and out of structures.
The entire industry of architectural thermal management is fighting against the predominating 4/5ths radiation as thermal loss then lying about it on tables online, around the world, claiming in structures actually are losing the majority of their heat via conduction and convection.
Because they’re part of big oil?
Because they’re against the science?
No what has happened is you’ve come into a field where every fake bulls ** story you tell is as easily checked
as simply comparing what you claim,
to what I, and hundreds of thousands, nay millions of others know, and have made a lot of our living displaying we know.
Your claim is that the millions and millions of people who have referred to architectural thermal management sites in being told most everything mankind can find to build with has a larger conductive/convective heat loss than radiative transfer
All those people are utterly clueless that right next to us, to them, all over the world, everything else has a 4/5ths radiant loss ratio and it’s only the wood, and stone, and paint that mankind has touched,
that has a predominating convective/conductive loss.
Do you understand the absolute maximum goofy associate with that claim Willis?
You should have but obviously you don’t. Well heres a hint:
that assertion pegs the ”absolute goofy” meter and keeps it pegged as you try to find anything to say, to keep from going and checking how everything loses heat, yourself.
Using something other than climate speculators’ assertions as your personal byword for scientific excellence because they’ve already got you claiming man made materials emit primarily conductively/convectively,
while forty feet away the very forest they were taken from
are busily radiating 4/5ths of theirs. No they are not. Not remotely.
No Willis which is why the only thing you can think of is “No it ain’t.”
There’s no such thing as a “man made vs natural materials” conduction/radiation ratio that everybody knows and remembers to refer to, when thinking about insulating, or heating, or cooling something.
There’s not a materials science on earth of any significance, which claims that material’s primary method of energy loss to the atmosphere is radiant.
Kristian says:
March 27, 2014 at 1:16 pm
“By his own Bootlaces” might one add dear and rare teller of sensible climate related science relative to the big Non-Warming issue that some seem to be letting slip away.
But maybe one or more will properly react to the fact that you wrote of 400Wm2 of (calculated) rising LW and not the DWIR substituted in insulting reply an then go on to tellus how it can, at 0degC he says, help to fry our eyeballs but not drive any realistic energy converter.
My nearest CH radiator to where I am sitting which can can belch out about 3kW when fed with 85degC watter can`t raise my little IR thermometer to 40degC even when placed one centimeter away from its metal surface nor warm my bare face against the -40 or so degC DWIR pouring in on me from the night sky through the bare glass of the window above it. NO?!
What you say Willis sounds like pseudo-science.
What this says, sounds much more like actual science:
How Much Water Is Evaporated Into the
Atmosphere Each Year?
On average, 1 meter of water is evaporated
from oceans to the atmosphere each year.
The global averaged precipitation is also
about 1 meter per year.ESS55
Prof. Jin-Yi Yu
How Much Heat Is Brought Upward By
Water Vapor?
Earth’s surface lost heat to the atmosphere when
water is evaporated from oceans to the atmosphere.
The evaporation of the meter of water causes Earth’s
surface to lose 83 watts per square meter, almost half
of the sunlight that reaches the surface.
Without the evaporation process, the global surface
temperature would be 67° C
instead of the actual 15° C.”
Evaporative cooling.
Convective cooling.
Conductive cooling.
Finally dead last, comes radiant transfer.
That’s what real science teaches about the real world.
Evaporative and Convective being spoken of as inter-related, the fact is, radiation comes dead last in the real world where people actually are right when they repeatedly assert something is science.
James Rollins Jr says:
March 27, 2014 at 5:29 pm
Still no observations facts, citations, or quotes to support your claims? I’m totally uninterested in your further claims until you come up with evidence.
w.
James Rollins Jr says:
March 27, 2014 at 5:40 pm
Dang, James, actual numbers. You surprise me in a good way.
Yes, I agree that somewhere around 80 W/m2 of energy is lost from the surface by evapotranspiration, and that this is around half of the solar absorbed by the surface. This agrees also with the KT energy diagram, as well as the CERES data.
Now, we know that the upwelling LW from the surface is about 400 W/m2. We derive these figures in a couple ways, both from ground measurements and from satellite measurements.
In addition, as we agree, about 80 W/m2 is lost from the surface by evapotranspiration. That makes 480 W/m2.
So … how much energy goes from the surface to the atmosphere by sensible heat.
I say it’s about 20 W/m2 or so. Estimates range from 15 to 20 W/m2. See Table 1b here for the estimates and their sources.
In order for your theory to be true, the total of sensible and latent would need to be well over the 400 W/m2 lost by radiation … which means sensible heat loss would have to be ~ 350 W/m2 for your idea to hold water.
Now, if you have evidence of that purported huge sensible heat loss of ~350 W/m2, bring it on … me, I’ve never seen it.
Regards,
w.
James: You could have saved yourself a huge amount of time and effort if you had simply said, “Willis, I think you should be talking about net radiative transfer from the surface, not gross radiative losses from the surface.”
That’s all your objections boil down to. Then we would have had something to discuss – when it is better to use gross flows and when to use net.
But even if we are talking about the net radiative transfer from the surface, it is about as big as the latent heat transfer, and significantly larger than the sensible heat transfer.
Willis: I had a fun problem today in my day job that is somewhat related to our discussions here.
One of our customers is using electronic power amplifiers whose heat sinks are black anodized to enhance the radiative transfer that helps cool it. In wiring up the system, they tried to ground the amplifiers through the heat sink surface, not realizing that the anodized layer is a very poor electrical conductor. The result was that they really were not grounded at all, which led to all sorts of spurious electrical problems.
Of course, you cannot enhance the radiative transfer to nearly the extent that you can enhance conductive/convective transfers (you cannot achieve emissivities higher than 1.0). I’ve recently been arbitrating arguments between our own power electronic designers, who want the most powerful possible fans on our heat sinks, and our marketing guys, who want the quitest possible fans. (With forced convection, you can get many times the transfer of free convection.) Always the tradeoffs…
In the climate system, two main parasitic losses are the losses from the surface to the atmosphere by way of conduction and convection (sensible heat), and the losses from surface to atmosphere by way of evaporation and transpiration (latent heat). Both of these parasitic losses act to reduce the surface temperature with respect to the overlying atmosphere, by simultaneously cooling the surface and warming the atmosphere
To me, what you are describing as parasitic loss, is actually the intended function of the system. It is the work that is needed to be done at the surface to transport the latent heat and sensible heat for release aloft. The “engine” doesn’t function until the temperature differentials develop via SWR, then the evaporation / lapse rate cause instability to develop and physically transport the heat away. The largest effect is transport of latent heat. The transport system emerges (as you have described before), which carries the energy aloft until water droplets condense, then the droplets act as black bodies and radiate the heat to space, nearly uninhibited by GHGs above at that point. The engine functions like any conventional air conditioner, using the condensing gas H2O, except that its primary heat rejection mode aloft is radiation. The process is a shunt that develops on demand to dump the excess heat basically directly to the drain (space), as you have also described as emergent phenomena. The more heat available, the more work is done by the condensing gas, until the energy is disposed of and the differential collapses. If this is a parasitic loss, what is the intended “work” of the system that is not a loss (its useful function)?
Kristian, you say:
“Your postulated DWLWIR flux is a component of the surface’s energy OUTPUT, not INPUT.”
So the downwelling flux is really the surface’s (upwelling) output. Down is up. Yikes! Orwell would be proud. That takes a level of confusion far more profound than I thought you had in you.
Heat transfer is a process, not a thing. Nobody (but you, apparently) believes in the 19th century caloric theory of heat transfer anymore. Please get into the 20th century, if not the 21st. Radiative heat transfer is simply the difference between two opposing electromagnetic radiation energy “flows”, as in upwelling vs downwelling. This has been well understood for a hundred years now.