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 …
I can’t believe the things I have seen you say in series, like when you were caught bald faced, not knowing nearly half the energy losses from the earth’s surfaces are from evaporation,
insulting credentialed peoples’ knowledge of the fields they make their livings in, suggesting they learn what they’re talking about,
being caught repeatedly – by and in front of all of us – not having the slightest clue what you’re talking about.
I’m really disappointed and I don’t see how anyone so obviously out of touch with thermodynamic reality – your 80% claim is a perfect example, along with your showing a measurement that clearly indicates 353 watts,
claiming proof that 400 watts per sq. meter is measured regularly..
You really are very confused Willis. That’s obvious, as these posts make it perfectly clear you don’t possess the intellectual honesty to confess you’re wrong when the information’s put right there on the page in front of you by me.
Something very serious is wrong with you if you believe just because somebody will publish it, you have the right to mislead people en masse with your bombastic and error riddled claims.
Here’s something I think every Jr College or High School Student has had: CalTech talking about methods of heat loss.
When referring to the common convective heat loss example we might all reflect on – we see the atmosphere mentioned expressly.
CONVECTION:
In liquids and gases, convection is usually the most efficient way to transfer heat. Convection occurs when warmer areas of a liquid or gas rise to cooler areas in the liquid or gas. As this happens, cooler liquid or gas takes the place of the warmer areas which have risen higher. This cycle results in a continous circulation pattern and heat is transfered to cooler areas. You see convection when you boil water in a pan. The bubbles of water that rise are the hotter parts of the water rising to the cooler area of water at the top of the pan.
You have probably heard the expression “Hot air rises and cool air falls to take its place” – this is a description of convection in our atmosphere. Heat energy is transfered by the circulation of the air.
Let’s see right after that if they mention the atmosphere when they discuss radiation since it predominates 80% Willis. LoL. Think so?
http://coolcosmos.ipac.caltech.edu/cosmic_classroom/light_lessons/thermal/transfer.html
RADIATION:
Both conduction and convection require matter to transfer heat. Radiation is a method of heat transfer that does not rely upon any contact between the heat source and the heated object. For example, we feel heat from the sun even though we are not touching it. Heat can be transmitted though empty space by thermal radiation. Thermal radiation (often called infrared radiation) is a type electromagnetic radiation (or light). Radiation is a form of energy transport consisting of electromagnetic waves traveling at the speed of light. No mass is exchanged and no medium is required.
Objects emit radiation when high energy electrons in a higher atomic level fall down to lower energy levels. The energy lost is emitted as light or electromagnetic radiation. Energy that is absorbed by an atom causes its electrons to “jump” up to higher energy levels. All objects absorb and emit radiation.
Not mentioned.
Here’s another place Willis that says – once again: you’re so wrong it’s not even possible that you don’t know it. You’re posing.
Here’s what they’re teaching people from the 9th grade to the 12th Willis.
Introduction to The Atmosphere
http://www.ucar.edu/learn/1_1_2_7t.htm
“Alignment to National Standards
National Science Education Standards
Physical Science,
Earth and Space Science,
Grades 9 to 12, pg. 189,
Item #3: “Heating of earth’s surface and atmosphere by the sun drives convection within the
atmosphere and oceans, producing winds and ocean currents.”
Benchmarks for Science Literacy, Project 2061, AAAS
“Convection currents are found in many places and on many scales, from huge convection currents in the atmosphere, oceans, and even in the earth’s interior to smaller convection currents found in a cup of hot cocoa or a fish tank.
Meteorologists usually use “convection” to refer to up and down motions of air. Heat gained by the lowest layer of the atmosphere from radiation or conduction is most often transferred by convection.
“Convective motions in the atmosphere are responsible for the redistribution of heat from the warm equatorial regions to higher latitudes and from the surface upward.”
——-
They aren’t talking about your fantasy, false, mythical 4/5ths transfer by radiation.
Here’s a remedial college teaching the basics to children in some online University.
it turns out, they’re using lessons that say the same thing Cal Tech said.
And that Ucar said.
“Convection leads to the counterintuitive fact that good insulators (like air) can transfer heat efficiently — as long as the air is allowed to move freely. Trapped air, as between panes of a double window, cannot transfer heat well because it cannot mix with air of a different temperature.
Radiation
Radiation is the simplest means of heat transfer. Heat radiation is carried not by moving atoms (as in conduction or convection) but by electromagnetic waves. Radiation is the only way that heat can move through a vacuum, and is the reason that even a closed thermos bottle (which has a vacuum between the inner and outer parts) will eventually come to the same temperature as its surroundings.
Heat transfer is most efficient by convection, then by conduction; radiation is the least efficient and slowest means of heat transfer. Low efficiency of heat transfer means that vacuums make excellent insulation.”
https://www.bluffton.edu/~bergerd/NSC_111/thermo1.html
But you, some amateur in here admitting you see it printed before your face, “about half the energy of the sun” are telling us all,
that’s all wrong? No. You don’t have the first clue how transparent the level of goofy is here, Willis that’s what’s going on. And your pretense this is like an opinion poll is another big clue something is seriously wrong with your thinking process about what you’re claiming.
It’s really a shame to see this kind of stuff put up by you as your perception of reality, Willis, I didn’t know you actually said things like I’m seeing you say.
You are in serious need of some education somewhere, besides wherever you had someone convince you, 80% of natural heat removal in the atmosphere occurs via radiant transfer.
Willis here is yet another site describing the atmospheric/surface relationship and it’s predominating convection action without
one
single
word
of the insane claim you made to everyone here that 80% of losses to the atmosphere are radiant.
http://web.physics.ucsb.edu/~lgrace/chem123/troposphere.htm
“The uneven heating of the regions of the troposphere by the sun ( the sun warms the air at the equator more than the air at the poles )
causes convection currents, large-scale patterns of winds that move heat and moisture around the globe.
In the Northern and Southern hemispheres, air rises along the equator and subpolar ( latitude about 50 to about 70 north and south ) climatic regions and sinks in the polar and subtropical regions.
Air is deflected by the Earth’s rotation as it moves between the poles and equator, creating belts of surface winds moving from east to west ( easterly winds ) in tropical and polar regions, the winds moving from west to east ( westerly winds ) in the middle latitudes.
This global circulation is disrupted by the circular wind patterns of migrating high and low air pressure areas, plus locally abrupt changes in wind speed and direction known as turbulence.”
There are many, many, many more, Willis, all of them talking on and on – about the convective nature of surface/atmospheric interaction without a single word of your bombast and I mean that not simply as an insulting thing to say but just referring to it as exactly, what it is. Utter fable.
There isn’t a single place in reality based energy mechanics that teaches 80% of energy loss in the atmosphere is via radiation.
Here’s yet another place Willis, that says outright
convection predominates and barely mentions radiative losses:
They say:
“The uneven heating of the regions of the troposphere by the sun ( the sun warms the air at the equator more than the air at the poles )
causes convection currents,
large-scale patterns of winds that move heat and moisture around the globe.
In the Northern and Southern hemispheres, air rises along the equator and subpolar ( latitude about 50 to about 70 north and south ) climatic regions and sinks in the polar and subtropical regions.
Air is deflected by the Earth’s rotation as it moves between the poles and equator, creating belts of surface winds moving from east to west ( easterly winds ) in tropical and polar regions, the winds moving from west to east ( westerly winds ) in the middle latitudes.
This global circulation is disrupted by the circular wind patterns of migrating high and low air pressure areas, plus locally abrupt changes in wind speed and direction known as turbulence.”
http://web.physics.ucsb.edu/~lgrace/chem123/troposphere.htm
“Convection is the mechanism responsible for the vertical transport of heat in the troposphere while horizontal heat transfer is accomplished through advection.
The exchange and movement of water between the earth and atmosphere is called the water cycle.
The cycle, which occurs in the troposphere, begins as the sun evaporates large amounts of water from the earth’s surface and the moisture is transported to other regions by the wind.
As air rises, expands, and cools, water vapor condenses and clouds develop. Clouds cover large portions of the earth at any given time and vary from fair weather cirrus to towering cumulus clouds.
When liquid or solid water particles grow large enough in size, they fall toward the earth as precipitation. The type of precipitation that reaches the ground, be it rain, snow, sleet, or freezing rain, depends upon the temperature of the air through which it falls.”
—————————-
To which Willis your reply has been – for how long I wonder – that you have thumbed your nose at reality to publish lies you know very well are just that. Never in your entire life anywhere on this planet were you taught that
“80% of surface losses to the atmosphere are radiant.”
No you did not. And the proofs are able to get very, very long Willis, because every place we visit we aren’t going to see one single mention of your totally mythical bullshoot story about
“4/5ths radiant losses.”
Sorry moderator I meant the second of those two last two posts, I thought I lost one, Thanks
James R
Oldseadog says:
It is high time someone put Willis up for an Hon. PhD.
Agree wholeheartedly.
It won’t happen [good ol’ boy network won’t allow it], but I learn more from Willis than from just about any PhD.
Messrs JRjr & K have written:-
A whole load of Established Science sense in response to the frantic drivel and patent mischief issued by W.E. and his obvious acolytes in defense of the “Warmist” claim that is the hand of GHG`s which are on the Earth Oven thermostat control in order to wrongly elevate the role of Co2 to that of being some kind of inbuilt radiant element that could turn the pie to toast if tweaked above the abysmal level Industrial Man inherited, upon which specious argument AGW has been built, and that its REAL LIFE role in Climatology is to help emit to Space the likely self assisted too surplus IR that has managed to negotiate its way through our maelstrom of an atmosphere below and to slough off some of the Suns N/IR similar to the way Ozone does its UV to give us a habitable surface on which to LIVE.
(AND) “upon which specious……..” tutt tutt!
When you decide to stop beclowning yourself, Mr. James Rollins Jr. You might want to review the KT diagram that Willis mentioned above.
http://citeseerx.ist.psu.edu/viewdoc/download?rep=rep1&type=pdf&doi=10.1.1.210.2513
Here’s another widely known site in outright contradiction of your claim Willis.
Wikipedia:”Convective Heat Transfer: The very first lines in the definition:
“Convective heat transfer, often referred to simply as convection, is the transfer of heat from one place to another by the movement of fluids.”
“Convection is usually the dominant form of heat transfer in liquids and gases.”
Shortened – http://goo.gl/B8fqg
James Rollins Jr says, March 29, 2014 at 7:27 am:
““Convection is usually the dominant form of heat transfer in liquids and gases.””
Which everyone and anyone should darn well know!
The other heat transfer mechanisms would basically get nowhere without convection as a transporter of the energy provided through the fluid (from heating end to cooling end).* If the air directly above the solar-heated surface didn’t buoy up and away instantly and automatically upon absorption of the conductively and radiatively tranferred energy from the surface (and hence warming), to make way for new transferred energy, then the heat would pile up down there, at the surface, in huge amounts. Convection is the process by which the surface heat is brought out into the atmosphere. Convection is the process that maintains the tropospheric temperature profile, that prevents energy from building up near the surface, that gets it up to where it can finally radiate out of and away from the system, through the conductive (‘convective’) insulation layer that is the troposphere.
*Well, evaporation actually helps with the convective lift.
The best way to illustrate this relationship, how conduction and radiation provides the energy going from surface to atmosphere, but as soon as this energy is absorbed into the atmosphere, convection takes over completely, is with the burning candle. The radiation streams out from the hot flame in all directions in equal amounts, up, down and to the sides. But that’s not where the HEAT ends up. Hold your hand just a few inches away from it to the side (or below it) and you can practically no longer feel its warmth. Hold your hand at the same distance only over the flame and you’ll burn right away. Convection does the job. The energy (heat) comes from the candle flame combustion, but it is all almost immediately absorbed by the air, which instantly warms, expands and lifts up. So the flame cannot make its surroundings any warmer outside of the ‘zone of free radiation’. Convection does not allow it. That is, IF we do not find ourselves inside a closed room. THEN the candle (and our presence) will after a while noticeably warm the room. But why? Because convection is suppressed by the walls and ceiling. The heated air in the end has nowhere to escape. Open a window, though, and the warming will soon be erased. Or light your candle outside in the open air (even on a dead calm night). No warming of the general surroundings. You have to move inside the ‘zone of free radiation’.
This is such a simple everyday truth, but no one seems to connect it at all with the large-scale global surface/atmosphere interaction.
You can’t just put so-called GHGs in the atmosphere and expect the lower part of the atmosphere to warm more than if they weren’t there. Because any excessive energy absorption (heating) would just be negated by convection right away. The tropospheric temperature profile is what it is. Established and maintained by the interaction between solar surface heating and convective response to set it up globally fluctuating around in generally close proximity to the adiabatic lapse rate. You don’t make it less steep by introducing ‘GHGs’ into the atmosphere. If anything, they would work toward steepening it, making heat transport (by convection) through the troposphere MORE efficient. And as we all know, those radiatively active gases are what enables the atmosphere to cool approprately to space. They are however NOT what enables the atmosphere to be heated by the surface.
James: You read but you don’t understand. It’s been repeatedly pointed out that Willis has been talking about GROSS radiative transfers in this post (because that’s what you can measure, and this post has been about radiative measurements and their variation), and you are talking about the NET radiative exchange.
Willis is correct about the general magnitude of the gross radiative losses from the surface. For a high-emissivity (say 0.95) body at 15C (=288K), any textbook will tell you that:
Q = e * sigma * T^4 = 0.95 * 5.67×10^-8 * 288^4 = 370 W/m^2
At 20C, it is 424 W/m^2.
These numbers are right in the range of what Willis was talking about.
Now, in the case of an atmosphere with greenhouse gases, as ours is, the NET radiative losses from the surface (which is what you are talking about) are much lower because of the downwelling radiation from the greenhouse gases. If the atmosphere did not have these gases, the gross from the surface would be the same as the net.
Kristian: In introductory calculus, you learn that when you perform the definite integral of a function, you need a constant of integration. So when you integrate the dT/dz lapse rate to try to obtain T(z), you need a constant of integration. With an atmosphere that is transparent to infrared, that constant is derived from the fact that the surface must be in radiative balance between sun and space.
With greenhouse gases, the constant is derived from the fact that this balance occurs at an elevation range higher up in the atmosphere. Given the lapse rate, this yields a higher surface temperature.
Curt says, March 29, 2014 at 9:56 am:
“It’s been repeatedly pointed out that Willis has been talking about GROSS radiative transfers in this post (because that’s what you can measure, and this post has been about radiative measurements and their variation), and you are talking about the NET radiative exchange.”
It’s also been repeatedly pointed out in this post that there are no GROSS radiative transfers. There is only what you would call a NET transfer. The transfer of energy between two objects at different temperatures is spontaneous and indivisible and goes only from hot to cold. You can’t apply the ‘macroscopic’ concept of splitting a radiation field between two such objects into two separate ‘streams’ of energy (as if they were two opposing highways) and then treat each of them independently from the other, as if they both were individual heat fluxes (they both heat the receiving system in your model!).
It’s not like the surface first heats a bit from the alleged incoming atmospheric flux and then cools a bit (only a bit more) by its resulting outgoing. There is ONLY cooling. The radiative transfer is from surface to atmosphere. And that’s it. Any ‘exchange’ would occur continuously and simultaneously as the radiation field between the two objects constantly adapts to their temperature difference (the potential gradient through the field), changing instantaneously with it. The spontaneous FLOW of energy (the only one that can be detected, meaning, the only ‘real’ one) between the two objects goes only ONE way, from hot to cold. Like an electric current. Like wind. This is the HEAT. It’s all there is. Everything beyond this is purely theoretical speculation and extrapolation.
What you can MEASURE, Curt, is the ‘heat’ (the NET). What you CALCULATE from this and any sensor’s temperature are the assumed individual (‘gross’) fluxes.
Curt says:
March 29, 2014 at 9:56 am
James: you read but you don’t understand.
—————————-
Your grasp of thermodynamics is best described as thinking space suits are insulated because it’s freezing cold in space Curt.
I’ll remind everyone who we’re dealing with in you:
“Curt says:
March 26, 2014 at 11:32 pm
James, you simply do not know what you are talking about. Inside an astronaut’s spacesuit, there are seven layers of aluminized mylar, each one providing a layer of radiative insulation, with the plastic mylar itself keeping the aluminum layers from conducting to each other.
The reason for this is that the human body produces about 100 watts through its metabolism. But the surface of the body radiates away close to 500 watts. Without the “back radiation” we are used to on the earth’s surface, without excellent radiative insulation, the astronaut would very quickly freeze to death when out of the direct line of the sun.
—————————-
That childish lack of grasp on reality on your part has had to be straightened out but you’re sure you’re all about thermodynamic understanding :
James Rollins says:
March 27, 2014 at 12:26 am
No Curt that isn’t correct actually about the space suits.
“Temperature
To cope with the extremes of temperature, most space suits are heavily insulated with layers of fabric (Neoprene, Gore-Tex, Dacron) and covered with reflective outer layers (Mylar or white fabric)
to reflect sunlight.
The astronaut produces heat from his/her body, especially when doing strenuous activities.
If this heat is not removed, the sweat produced by the astronaut will fog up the helmet and cause the astronaut to become severely dehydrated;
astronaut Eugene Cernan lost several pounds during his spacewalk on Gemini 9.
To remove this excess heat,
space suits have used either fans/heat exchangers to blow cool air,
as in the Mercury and Gemini programs,
or water-cooled garments, which have been used from the Apollo program to the present.”
From N.A.S.A. : How SpaceSuits Work:
Parts of a Spacesuit
NASA spacesuits have many pieces and parts. Learn about the parts and why each piece is important.
Primary Life Support Subsystem
The PLSS is worn like a backpack. It provides astronauts many of the things they need to survive on a spacewalk. Its tanks supply oxygen for the astronauts to breathe. It removes exhaled carbon dioxide. It contains a battery for electrical power.
The PLSS also holds water-cooling equipment,
a fan to circulate oxygen and a two-way radio. A caution and warning system in this backpack lets spacewalkers know if something is wrong with the suit. The unit is covered with protective cloth layers.
Layers
The spacesuit arm has 14 layers of material to protect the spacewalker. The liquid cooling and ventilation garment makes up the first three layers.
—————————-
Whatever you do for a living you don’t have formal thermodynamics handling training or you’d have understood the insulation isn’t on equipment in orbit “because they will freeze to death!”
Your grasp of the entire thing is well summed up by your charging in here trying to preach the above class of amateurish wishing.
It’s not even like you can even say you were wrong through some typo. You vomited out your amateur answers in front of professionals who caught you trying to fake it.
Kristian: You say,
“It’s not like the surface first heats a bit from the alleged incoming atmospheric flux and then cools a bit (only a bit more) by its resulting outgoing.”
That’s exactly what is happening (although simultaneously, not sequentially). Every photon absorbed adds to the surface’s internal energy, every photon emitted reduces its internal energy. This has been well understood for a hundred years now.
You also say, “You can’t apply the ‘macroscopic’ concept of splitting a radiation field between two such objects into two separate ‘streams’ of energy (as if they were two opposing highways) and then treat each of them independently from the other, as if they both were individual heat fluxes (they both heat the receiving system in your model!).”
Sure you can split them, because that is exactly what is happening in the underlying physics. (And I don’t know why you would call this the “macroscopic” concept – you can use the “macroscopic” metaphor of heat flow to talk about it simply; I’m talking about the “microscopic” mechanics.) The opposing “streams” both carry energy, reducing the energy of the body emitting them and adding to the energy of the body absorbing them.
You continue to treat heat flow as something real, rather than a convenient metaphor. This is why it is so easy to mock you as being stuck in the 19th century, when they had no way of knowing better. What is the underlying physical entity transferring your supposed one-way real heat flow — the “heaton”?
Have you ever studied statistical mechanics, radiative physics, or even engineering heat transfer? All of this is treated early in any of those courses.
James: You seriously miss some very important points here. Let’s break them down into baby steps.
First, the human body’s rest metabolism produces about 100 watts. With exertion, you can produce more for intermittent periods.
Just considering an adult’s torso alone, the skin is about at 35C with an emissivity of 0.97. There is about a square meter of surface area on the torso. So the radiative power output from the torso alone is:
P = e * sigma * T^4 * A = 0.97 * 5.67×10^8 * (273+35)^4 * 1.0 = 495 watts
Of course, your limbs will be radiating as well, probably from a slightly lower temperature, but we’ll ignore that for now, and just say that the body is radiating away 500 watts on a continuous basis. So far we are at a 400 watt deficit that has to be made up somehow.
Now, let’s consider the point of the thermal design of a space suit. It has to make sure that the astronaut neither overheats nor freezes under any of the foreseeable conditions. The astronaut can be in sunlight or shade, can be exerting heavily or at rest.
Let’s consider the similar problem of going outside on a cold winter’s day. You may be in sunlight or shade; still air or wind; and you may be working hard or at rest. Do you take enough insulating clothing (here we are talking primarily about conductive/convective insulation, but radiative can help) to handle the worst-case “cold” conditions (lowest expected temperature, shade, wind, rest), being able to open them up (e.g. unzipping the parka) or remove them in warmer conditions, or do you only bring enough for warmer conditions and count on some separate energy source to help when the conditions get colder?
Obviously, it’s the first case. Many people have died of hypothermia attempting the second strategy.
So it is also with space suit design. The suit must be insulated with the worst-case “cold” conditions in mind – rest metabolism and shade conditions. In this case, there are no conductive/convective losses to ambient in space, so we are concerned primarily with radiative insulation. We must make sure that the body’s losses are only about 100 watts to match the metabolic gain. This is achieved primarily by using multiple layers of reflective radiative insulation, so the inner layer can reflect back about 400 watts.
Now, what happens if things are not worst case – the astronaut is exerting himself and/or in the sunlight?j Well, the radiative insulation does work both ways, so that helps, and there is a reason all spacesuits are white, to reflect as much sunlight as possible. But with just a passive system, the astronaut could overheat.
Now, if you start working hard when you are outside on a winter day on the earth’s surface, can open up your jacket to permit more losses to ambient. In space, of course, it is not possible to do this in the same way.
But you can get the same effect by running coolant over the surface of the body and passing it to the outside of the insulation (through very small gaps in the insulation). Once outside, it is very easy to radiate the energy out to deep space. The only power that is needed is a few watts to drive the pump motor.
So the thermal strategy of spacesuit design is to overinsulate radiatively, then add an active cooling system to regulate the interior temperature. This requires a far smaller energy supply (battery) to be carried along, because a few watts to the pump motor can dissipate hundreds of watts of thermal power. If the suit were underinsulated, the battery would have to supply every watt of added thermal power.
It’s not a good idea to rely on stuff written by NASA PR flacks as being authoritative technical sources. They seldom get the subtleties right, and often miss the basics as well. I have seen some truly awful stuff out of them, far worse than Wikipedia.
Thanks Curt. Keep up the good fight. Love reading your analysis.
Willis,
I am concerned about the impact of one possible oversimplification in your analysis, you assume a simple surface that either gets rid of input energy via upward IR or other losses to the atmosphere. Here are you relevant quotes:
“The parasitic loss is computed as the input to the surface less the radiative loss from the surface.”
“In terms of the greenhouse effect, the efficiency can be thought of as how hot the greenhouse effect can make the surface with respect to the atmosphere.”
“Otherwise, in addition to losing energy via radiation the heat can “leak” from the surface to the atmosphere.”
“The parasitic loss is computed as the input to the surface less the radiative loss from the surface. There is an uncertainty in the measurement due to the import/export of warm water from a gridcell, but that appears to be minor in the context of this particular analysis.”
It seems to me what the analysis is missing is the depth of that gridcell and the heat capacity of the ocean water. Most of the solar SW input will probably be deposited in the top few meters, but as someone who lives in the tropics, you know that some SW radiation penetrates 10s of meters, and there are even kelp forests over 100 meters deep. It appears to me that heat stored in the ocean is a “parasitic loss” in your analysis, not a loss to the atmosphere on the time scales being considered. This might be a figure so small as to be in the noise in your analysis. We heard frequently, especially in response to the “pause”, that 90% of AGW global warming heat is stored in the ocean. This however, is 90% of the net energy imbalance, variously quoted as from 0.6W/m^2 to 0.8 or 0.9W/^2 globally and annually averaged. This gridcell depth may be much less of an issue for LW/IR radiation since it penetrates mere microns into the ocean and it thus closer to the idealized surface or skin effect. Models that couple LW radiation to the whole mixing layer just like SW, would miss the enhanced surface coupling of the LW radiation. I wonder if this enhanced LW coupling to the complex ocean surface (foam, waves, etc) might result in the enhanced feedback you are seeing with increased input.
Hmmmmn.
Gonna have to disagree with you here, Willis, on a couple of points.
Granted, you are working with averages from CERES – and THAT may be the fundamental problem! – but, for example, the earth receives just a little under 1000 watts/m^2 between the tropics of Cancer and Capricorn all year, (at noon) and each square Mkm^2 gets that radiation only around noon each day.
The initial graphs, stopping at 600 watts/m^2, would be misleading then, right?
So, should we not begin instead with the plots for the parasitic losses over 24 hours for each latitude; then attempt to improve on that approximation by incorporating the percent of land/snow/ice/water being hit by the that calculated radiation for each 5 degree latitude band from pole to pole?
Instantaneous losses from
Radiation.
Convection.
Conduction.
Evaporation.
vs the (somewhat simple to calculate) instantaneous heat input for that minute from the sun.
All parasitic heat losses are instantaneous: Most vary directly by delta T (from surface to local air temperature or from the surface to the ultimate radiation absorber in the stratosphere) and a constant that varies instantaneously with pressure, contact conditions (conduction), geometry of the two surface (convection changes with wind velocity, humidity, heat surface locations, fluid conditions (Prandlt number, Nusault number, Raleigh number, relative turbulence, length of constant area, etc.), humidity or surface condition (emissivity of both surfaces for example, percent of pressure between surfaces, type of roughness of surfaces, etc).
All heat losses occur ONLY due the immediate local conditions, and cannot be “recalled” or changed once losses occur. No one should make global assumptions from global averages over the year, because that is NOT how heat transfer occurs. Heat transfer – fro a hot surface to ta cold surface depends immediately and ONLY on the immediate conditions of those two environments at that particular second in time.
So, the net impact can ONLY be judged looking at EACH particular instantaneous situation at EACH particular latitude and assumed weather condition (temperature of surface, wind speed at 2 meters, air temperature, sky condition, pressure, relative humidity, T wet bulb, T dry bulb.) What IS important at the equator at noon is irrelevant at the Antarctic in the winter, but the “delta T” difference between each of the two surfaces, might even be the same. Or be very different! Radiation losses, for example, in the arctic will change because the surface (ice or open water) are very different temperatures in degrees K.
But, air temperature could be the same all day, but 3 hours of evaporation losses alone will be larger than the entire days’ heat gain from the sun. Parasitic heat losses from an open water at 2 degrees C into an air temperature of “only” -15 C will vastly different from a ice-covered surface also -15 degrees C into that same arctic air at -15.
When the Arctic is getting well under 200 watts/m^2, but parasitic losses are 50 or 100 or 150 watts per m^2, then much more precise definitions and calculations of those exact parasitic losses are critical to the problem.
For example, if air temperature is 35 C, surface water temperature = 15 C with 2 m/sec wind at 2 meters and relative humidity = .85%, what are the evaporation and convection losses and radiation losses into a sky covered with clouds in the the stratosphere at -30C?
Input SW radiation at noon = 1030 watts/m^2. Do small parasitic losses matter?
Input solar (SW) radiation at midnight = 0, input long wave (LW, proportional to Tsky^4) radiation at midnight = ???? watts/meter^2.) Do parasitic heat losses matter now? 8<)
Now, change that problem to the Arctic or Antarctic: If air = -15 C, water = 2 C, wind = 4 M/sec, and the the relative humidity is 45% (for -15 C !!!) what are the parasitic losses?
Yes I did see it, and so did everyone else. You’re another amateur faking it online.
Curt says:
March 29, 2014 at 4:08 pm
You didn’t see me show up claiming outer space is freezing cold removing heat faster than convection or conduction. You didn’t see that.
You also didn’t see me try to crawfish out of it through desperately talking in circles, then claim that N.A.S.A. and other educational organizations don’t know as much as me.
Please say you didn’t see that and you can forget I revealed how little I actually understand.
Come on James, this is trivial introductory undergraduate stuff. Do the numbers for yourself!
Repeating from above, the skin of the human torso is about 1 m^2 at 35C with 0.97 emissivity. This gives a radiative power output of:
P = e * sigma * T^4 * A = 0.97 * 5.67×10^8 * (273+35)^4 * 1.0 = 495 watts
Conservatively, I’ll add the outer surface of the limbs at another 0.5 m^2 at 30C, again with 0.97 emissivity, for additional radiative power output of:
P2 = e * sigma * T^4 * A = 0.97 * 5.67×10^-8 * (273+30)^4 * 0.5 = 232 watts
So that’s a total of about 725 watts, far higher than the body’s rest metabolism of 100 watts generated internally.
Now in normal earth surface conditions, you are surrounded by surfaces that are not much colder. If you are inside, you are surrounded by high-emissivity walls at about 23C. These radiate at a power density of
Q = e * sigma * T^4 = 0.97 * 5.67×10^-8 * (273+23)^4 = 422 W/m^2
So your 1.5m^2 of body surface is receiving 422 * 1.5 = 633 watts of radiant power, for a net outward radiative power flow of about 90 watts. You would also lose similar power by conduction/convection, which is why you would want some clothes on you at rest at an ambient of 23C.
Now, in space and out of the sun, you would have no conductive/convective losses, but virtually no ambient radiation toward you (the cosmic microwave background radiation is less than a microwatt per square meter). So without radiative insulation, you would have a power imbalance of over 600 watts. That could not be maintained for long.
When astronauts expel urine from the space ship, it immediately evaporates from the lack of pressure, but then almost immediately freezes into crystals. It is not losing heat from conduction or convection – it is from a huge radiation imbalance.
Curt there’s a way a man talks when he’s a professional whose work is always right.
We don’t swear we can do all the calculations – then spray the crowd like a pimple, with the insanity that comes out of the self taught amateur:
“That’s why they have insulation on those space suits – cause it’s so cold out there!”
The kind of unforgivable thermodynamic errors you’ve made don’t vanish because you gin up and try to Manic-Magpie yourself into some respectability.
Posers – such as yourself all swear you can do all the calculations,
and yet are notorious for doing what you and Willis have both done: make statements the entire educated world knows are the height of folly.
For those wondering if you, Curt actually know what you’re saying, when you claims you “calculates” your, and Willis’ folliy – a purely radiative surface –
here’s the difference between a professional thermodynamicist and some amateurs who washed up on the internet insulting the professionals, willing to give away their analyses free.
That’s because no one will pay money for it.
For those of you who aren’t trained math heads,
I’m gonna explain to you the kind of “work”
being done by Willis
and by Curt.
Being a professional who’s had to explain the ins and outs of thermodynamic flows to clients and various people I don’t need a long time to do it.
I’ll just do it the same way I would, If I had showed up and someone said “I had some guys over here and they claimed they did all the calculations and everything but they can’t come up with a right answer to save their lives: can you help? If you can, my company’s contract is effectively yours, because something’s obviously wrong with what these guys are doing.”
So the client takes the “work” done by Willis
the amateur
and the client takes the “check” of his work by Curt
the amatuer,
and we see they both insist none of the rest of us – the actual professionals – know what we’re talking about because
“They Did The Calculations” and “They Checked Each Other.”
If you are a reader trying to see who, is checking on whose work, finding it in error, watch –
– this is gonna take about 15 seconds for you, the non math-trained reader,
to understand why trained, experienced, knowledgeable certified thermodynamics professionals,
stay in business.
And you’re going to see why amateurs, are always getting caught: busted: outright: so wrong it’s literally something you take back to the office and show the other
certified professionals, what’s trying to pass itself off as “analysis.”
Ya know how Curt and Willis have gone on, and on, with their “I calculated,” – ?
Let’s do a real quick flyby on these two and see how “calculated”
their so-called “calculations”
really are.
—————————-
Willis Eschenbach says:
March 28, 2014 at 12:50 pm
“Here is the whole equation:
Radiation (w/m2) = S-B constant * emissivity * Temperature ^4”
—————————-
Ok.
Now here we have Curt: the other amateur: proudly claiming he’s checked, and he sees it just that way, too:
“Curt says:
March 29, 2014 at 9:56 am
“Willis is correct about the general magnitude of the gross radiative losses from the surface. For a high-emissivity (say 0.95) body at 15C (=288K), any textbook will tell you that:
Q = e * sigma * T^4 = 0.95 * 5.67×10^-8 * 288^4 = 370 W/m^2
At 20C, it is 424 W/m^2.”
—————————-
What these two amateurs are trying to do, is calculate the amount of energy, leaving the surface of the earth.
What they’ve done, is calculate it
using the wrong calculation.
Look for yourself. Here’s the page of something called “The Engineers’ Tool Box.”
Here is the page, at the Engineer’s Tool Box, that describes the calculations for radiative loss.
Just look at the page and specifically, look for something called “Hc” or the
“hc= convective heat transfer coefficient of the process”.
Now what the Hc or convective heat transfer coeeficient does, is include the amount of heat removed by the air.
Do you see the proper accounting for the convective removal by the atmosphere itself, these amateurs are advising you all, about?
No you don’t. The two amateurs who have been telling the professionals we need to learn to count,
forgot the air when they calculated losses from the earth’s surface.
http://www.engineeringtoolbox.com/radiation-heat-transfer-d_431.html
Right there above is the page with the radiation transfer calculation.
Notice it is identical to the one the two amateurs are using to calculate losses from earth’s surface.
Notice there’s nothing there even acknowledging the air removes anything at all?
That’s because the two amateurs don’t even have the correct calculations for removal of energy from the surface of the earth.
The Atmosphere removes part of the heat from the surface of the earth: the amount that is taken off by convection is a function of the difference between the temperature, in the solid and the fluid washing it which is in this case, atmospheric air.
http://www.engineeringtoolbox.com/convective-heat-transfer-d_430.ht
Notice the real calculations for determining the surface of the earth, take into account the temperature and thermal transfer of air – just like you’d expect.
Instead, these two amateurs have spent a week in here, arguing with us, insulting the people correcting their horrifically mauled assertions of a physical world that simply can not be:
You’ve seen now yourself: we all know that regardless of what some wannabes on the internet say, the air takes a lot of energy directly from the surface of the earth through non radiative means.
These two have taken the calculations for an object without any atmosphere at all, and tried to claim they’re the calculations for a surface for an atmosphere –
yet I just showed you the calculations for a surface with an atmosphere touching it: a gaseous ‘fluid’ environment that removes heat conductively, and convectively.
You can see that even a casual pass by these peoples’ backward, error riddled fantasies, shows they don’t even grasp, they’ve tried to calculate the temperature of the surface of the earth,
having forgotten the atmosphere even is there. Thats what the “Hc” portion is, in the “Convective Heat Transfer: page: the effect of the atmosphere.
Look above at Curt – smart mouthing me, smart mouthing others – in here telling us all that the reason space ships have insulation is because it would be so cold in space without it.
Then when he’s shown to be utterly, utterly reversed, he goes on the long, amateur hour, Manic-Magpie “You didn’t catch me because I’m still typing” expedition.
From there he’s on to “I calculated the temperature of the surface of the earth. I forgot to include the atmosphere like real mathematics requires.”
And he’s still fervently typing to try to save something he perceives as a reputation.
Curt doesn’t have a reputation to damage. Neither does Willis. They’re amateurs, arguing with professional thermodynamicists who have
while you watched –
simply let they themselves express to you, their grasp of atmospheric energy and thermodynamic fundamentals.
They both forgot to include the atmosphere at all.
Look for the atmosphere in their calculations. It’s not there, is it.
No it is not.
That’s why these people despise the real, thermodynamically trained professionals, coming around checking their bullshoot stories.
Because everything they do and say is so easily debunked and not only is it easy, there’s no place for them to hide, because their own words
are what they’re defending here. It’s not like they’re defending someone else’s words, they came here and volunteered that
when calculating the amount of energy radiantly leaving the surface, you don’t even need to acknowledge the atmosphere is there in your calculations. Just calculate it like there’s no atmosphere.
That’s who is in here trying to act snide to their betters. The amateurs caught by the professionals not even knowing they have to include the atmosphere in their calculations for earth.
With regards to your Figure 1 the North African and Arabian deserts are glaring at me. It’s a big area and it would seem that there should be a large loss in upwelling IR to space if the deserts were to be considered to have a dry atmosphere. That doesn’t seem to be the case there. Could there be a stratification in the upper atmosphere containing high level water vapor near 100% RH effectively creating a GHG effect even though the low altitude is very dry?
I have returned to this post numerous times. It is interesting. I think the plots may offer more than what has been discussed here. A future post expanding on the data presented here would be most welcome.