Page 1 2 3 4 5 6 7 8 9 10
Go  |
New |
Find |
Notify |
|
Reply |
|
Admin |
New PM! |
|
quote: Originally posted by Steve_M:
egads! Given the same cool weather and the same (positive) boiler output, adding loft insulation will initially cool the loft.
How? Explain. quote: Originally posted by Steve_M:
If the boiler is unconstrained by thermostat, the house will get warmer and reach equilibrium at a warmer temperature. The loft will probably remain cooler, than it was because the warmer house will lose a higher proportion of its heat through walls and windows.
I am surprised that someone like yourself cannot (or is it will not?) understand the fundamental thermodynamic principles. quote: Originally posted by Steve_M:
There is nothing in the fundamental thermodynamic principles that tell you the exact temperature distribution unless you know all the details of the energy inputs (sun or boiler or both), energy outputs (through walls, windows and loft, or out of the top of the atmosphere), and transfer of energy through the system (radiative, convective, conductive, dynamic transportation).
Except one constant applies that heat transfer will apply and that transfer will be from a hot body to a cold body. quote: Originally posted by Steve_M:
Once all this is added to the mix, the models predict a cooler stratosphere caused by an increase in GHG concentrations, and a cooler stratosphere is what is observed which is one of the thousand pieces of evidence that attribute the current warming climate to the increased concentration of GHGs.
Taking this at face value - a cooler stratosphere will cause heat to be transferred from a warmer troposphere leading to a cooler troposphere. Yes there may be multiple facets with regards to heat sources and these sources may alter, and transfer rates will vary according to properties of the matter conducting or convecting the heat but the underlying principle is the same - heat will travel from hot to cold in an attempt to get to an equilibrium, irrespective of the materials involved, and all convoluted theories must work within that framework - unless you can prove the fundamental thermodynamic principles are flawed. |
| |
|
|
quote: Originally posted by APL: quote: Originally posted by Steve_M:
egads! Given the same cool weather and the same (positive) boiler output, adding loft insulation will initially cool the loft.
How? Explain.
You're kidding, right? Do you understand what insulation is? quote: quote: Originally posted by Steve_M:
If the boiler is unconstrained by thermostat, the house will get warmer and reach equilibrium at a warmer temperature. The loft will probably remain cooler, than it was because the warmer house will lose a higher proportion of its heat through walls and windows.
I am surprised that someone like yourself cannot (or is it will not?) understand the fundamental thermodynamic principles.
Touche!. You really haven't a clue have you? quote: quote: Originally posted by Steve_M:
There is nothing in the fundamental thermodynamic principles that tell you the exact temperature distribution unless you know all the details of the energy inputs (sun or boiler or both), energy outputs (through walls, windows and loft, or out of the top of the atmosphere), and transfer of energy through the system (radiative, convective, conductive, dynamic transportation).
Except one constant applies that heat transfer will apply and that transfer will be from a hot body to a cold body. quote: Originally posted by Steve_M:
Once all this is added to the mix, the models predict a cooler stratosphere caused by an increase in GHG concentrations, and a cooler stratosphere is what is observed which is one of the thousand pieces of evidence that attribute the current warming climate to the increased concentration of GHGs.
Taking this at face value - a cooler stratosphere will cause heat to be transferred from a warmer troposphere leading to a cooler troposphere. Yes there may be multiple facets with regards to heat sources and these sources may alter, and transfer rates will vary according to properties of the matter conducting or convecting the heat but the underlying principle is the same - heat will travel from hot to cold in an attempt to get to an equilibrium, irrespective of the materials involved, and all convoluted theories must work within that framework - unless you can prove the fundamental thermodynamic principles are flawed.
[/quote] They are not flawed but your understanding of them is. |
| |
|
|
quote: Originally posted by TrueSceptic:
They are not flawed but your understanding of them is.
Then please educate me. |
| |
|
|
Oh, look how sweet. Climate Report are out there picking cherries in June. Send them my regards, I do hope they enjoy themselves.  |
| |
|
|
quote: Originally posted by CobblyWorlds: Oh, look how sweet. Climate Report are out there picking cherries in June. Send them my regards, I do hope they enjoy themselves.
Unsurprisingly, the Swiss keep careful records of their glaciers, and they have a really nice website: http://glaciology.ethz.ch/messnetz/,It has: -maps, - summary lists that can be sorted different ways, - a picture of each glacier, - graphs of the advance/retreat since 1893, showing both yearly changes and accumulated change -the raw data. They also summarize, for a selected year, advanced & retreats for the glaciers they measured that year: 2006: 84 retreats, 1 advance |
| |
|
|
Thanks for that John M,
I couldn't even be bothered countering such a point.
|
| |
|
|
quote: Originally posted by APL: quote: Originally posted by TrueSceptic:
They are not flawed but your understanding of them is.
Then please educate me.
Can we start with http://en.wikipedia.org/wiki/Laws_of_thermodynamics (or another list you prefer)? Once we agree on the laws we can look at what happens in houses and lofts when we alter insulation between them (or indeed any other 2 adjacent volumes). |
| |
|
|
APL.
Quote.
Then please educate me.
EOQ.
________________________________________________
Before I deal with this quote addressed to TrueSceptic please allow me to offer my sincere apology for my first posting on Wiki reference. It is apparent that this post has confused your thread by introducing a second subject close to the original subject of your thread (compounded by my reply to Steve_M on my post clarification). This confusion was unintentional!
________________________________________________
To deal with this quote.
First of all, I'm quite sure that you need no further education. I believe that the original 'terms of reference' have been lost due to the confusion of the two subjects (I stand guilty here).
I only ask that you give thought to the reason why 'radiation' is included with 'thermodynamic principles'. Please remember that 'thermodynamics' is a macroscopic study of 'molecular' behaviour with 'vector kinetics' and needs to explain any great 'radiative' losses, or inclusions, from its mathematical modelling.
|
| |
|
|
quote: Originally posted by TrueSceptic:
Once we agree on the laws we can look at what happens in houses and lofts when we alter insulation between them (or indeed any other 2 adjacent volumes).
Just to be clear So which laws disprove my point? And which laws prove the view that a temperature drop will occur through applying loft insulation? Then there is the all important process of making sure that small changes don't get exaggerated out of proportion as often happens with AGW micro-analysis. |
| |
|
|
quote: Originally posted by suricat:
I only ask that you give thought to the reason why 'radiation' is included with 'thermodynamic principles'. Please remember that 'thermodynamics' is a macroscopic study of 'molecular' behaviour with 'vector kinetics' and needs to explain any great 'radiative' losses, or inclusions, from its mathematical modelling.
What ever that molecular behaviour is in the microscopic study it will still need to comply with the behaviour in the macroscopic. In other words no matter how molecules behave in raising or lowering temperature at the microscopic level the results must comply with expected results in the macroscopic. You cannot delve into the microscopic take some behaviour and then use that to derive an incorrect explanation such that a warmer troposphere leads to a cooler stratosphere ignoring the fact that fundamental thermodynamics still applies at the macroscopic level such that a cooler stratosphere will lead to a cooling of the troposphere regardless. And to complicate matters further all heat sources and types of molecules their effects, interactions and contribution to temperature changes need to be understood. So it's no good using loft insulation to explain CO2 effects on temperature. |
| |
|
|
quote: Just to be clear
So which laws disprove my point?
And which laws prove the view that a temperature drop will occur through applying loft insulation?
This is a reversal of logic. You are claiming that a cooling stratosphere must result in a cooling atmosphere. I am using the example of a loft to show that the laws of thermodynamics do not demand this, and that neighbouring objects can have opposing temperature profiles if other boundary conditions change. (Just to repeat, the loft example is not an analogy for the stratosphere. As I understand it, the increase in concentration of CO2 makes the stratosphere a more effective radiator of energy.) |
| |
|
|
APL, quote: Taking this at face value - a cooler stratosphere will cause heat to be transferred from a warmer troposphere leading to a cooler troposphere.
Unless I have totally misread you I think I can explain. The key is that over all the atmospheric energy fluxes there are flows inward and out depending on the constituent gasses of the different layers. Some gasses absorb incoming Visible or Ultraviolet (UV) from the sun, some the infra-red from the surface. The stratosphere gets warmer as you go up, the point is it is now cooler than at the start of the satellite record. But the heat flow "by conduction" will still be up from the troposphere into the stratosphere. the point is conduction is not the only, or indeed major flux of energy from the surface upwards. In the stratosphere the higher you go the warmer it gets- the dominating energy source here is the Sun. And Greenhouse gasses have negligible effect because they don't interact strongly (at all?) with visible. However in the troposphere the importance of conduction falls as pressure drops off. As pressure drops off so radiative energy transfer takes over as the major impact on temperature. Because the Sun radiates in visible light (Incoming shortwave radiation) and the atmosphere allows much of this through, the ground absorbs solar radiation and warms - that drives the whole atmospheric system. The Sun emits at an "effective radiating temperature" of about 6000 kelvin - most of the light is in the visible and ultraviolet spactrum. Whereas the Earth - having been warmed by the Sun emits at an "effective radiating temperature" of about 255 kelvin which means the radiation from the earth into space is in the infra-red. The ground warming drives turbulence in the boundary layer(BL), the lowest 3km of the atmosphere. This is why the BL is termed well-mixed. In the BL the main means of heat transfer is convection- hence it's turbulence. In the troposphere Infra-Red(IR) radiates up through the atmospheric column, but the pressure gets less and less, so gradually more and more IR is able to be emitted to space. (High density of greenhouse gas molecules so "spectral saturation" - like hitting the maximum volume on an amplifier - when you hold your hand up to the Sun you don't feel warmth from IR - you feel it from the visible and UV the Sun emits - the heat from a hot black pavement is IR) If you increase the amount of IR trapping molecules in the atmosphere, this has the biggest effect in the troposphere. They trap more IR and so reduce the amount of IR going upwards. Now that is a reduction in the flux of IR going through the stratosphere out into space. So it's a reduction of the energy available in the Stratosphere. Thus the Stratosphere cools. The Stratosphere still contains greenhouse gasses, although much less than the mid troposphere and below. In the case of an increase in solar radiation you get more absorption of UV in the Stratosphere so it warms. Likewise a Plinean volcanic eruption will spout ejecta that can reach the stratosphere (e.g. Vesuvious( Pliny the younger and his description of the destruction of Pompei) Mt Pinatubo, El Chichon, Mt Agung), that too traps sunlight and causes warming (may trap IR as well) - that cools the planet though. I'm pretty sure I got that right. And I'm hoping if you (APL) get this, then you'll see that thermodymics are satisfied. |
| |
|
|
APL.
Thank you for your response.
I agree to a point that, "it's no good using loft insulation to explain CO2 effects on temperature". Especially within the stratosphere, though this is a safer atmospheric region for radiative calculations! However, I didn't propose that it was! Perhaps you may wish to ask Steve_M, or CobblyWorlds about this proposition!
I would like to see a constructive level of discourse here. I've not once mentioned CO2 (apart from an aside in my 'Wiki' post), but as you've mentioned it to me I don't know how a 'radiative model' of CO2 can be used as a 'radiative' model for the whole Earth atmosphere with any accuracy because:
1. The troposphere contains a compound in 'tri-phase' (H2O) which 'vectors' thermal energy to unknown local regions (both 'radiatively' and as 'latent heat') outside of any 'radiative' mathematical model's parameters (it produces a 'mathematical black hole', or 'clerical error').
2. I'm sure you realise that the only 'radiative shell' of any consequence in this 'math mod' is the 'escape shell' and its 'depth'/'whole atmosphere depth' that permits heat (as this is the heat energy in focus as IR) to exit the system. In many places, this 'exit' is open, extends to ground level in some of those places and is to a great extent, still 'unsaturated'. This gives a 'patchwork' of 'some bits compute and some bits don't' in the 'math mod'.
I really don't want to continue with this CO2 stuff because my subject (taken up from the Wiki reference) was O3, or the lack of it. I'll stay quiet until this CO2 thing is resolved, but I do want to comment on just one thing.
quote:
Originally posted by suricat:
However, I do understand the thermodynamics involved and they do not apply in this case. Unless cloud, other aerosols, or particulates diffuse the 'line of sight' UV insolation, the UV strikes ground zero. It does, sunburn levels are a coarse measure of this and it has increased. I'll say no more without your acceptance.
Thermodynamics always applies. Fundamental thermodynamics are simply that a hot body will always transfer heat to a cold body until equilibrium is reached and cannot be stopped although it can be slowed. In your example the hot body is the sun the cold body the earth thermodynamics applies.
So if the stratosphere is cooler than the troposphere fundamental thermodynamics will dictate that the stratosphere will cool the troposphere regardless of what's in the way to slow the transfer.
Also if the atmosphere consisted of super-insulators, as is often attributed wrongly to CO2, then there would be a lag in the time it takes to dissipate the heat such that we would not experience the rapid changes in temperature that we do on a daily basis, because the heat transfer would be slowed (but not stopped) between the sun and the earth, and the earth and space. This is an simplistic view I know but never-the-less thermodynamics still applies.
EOQ.
What 'you' state here is true. However, it does not relate to my posting.
'Near' UV levels at ground level have increased. Even the recent UV level addendum to our local UK weather forecast reinforces this. When solar UV reaches ground level it has effected 'no atmospheric interactions' that have changed its wavelength, although it may have been 'diffused' within the atmosphere. Therefore it arrives as a 'radiative insolation component' to 'albedo' that contains no thermal dynamic other than an 'incoming radiation' containing NO 'heat' component, 'yet'. Thermodynamics can not apply until an 'interaction' occurs ('absorption' and 'emission at another wavelength') that leaves some 'heat' at the point of interaction!
Apology if the format is bad, but my time is short at the moment.
Respectfully,
suricat.
|
| |
|
|
Suricat quote: 'Near' UV levels at ground level have increased.
Do you or anyone else know by how much the average level of UV energy reaching the ground has increased in Watts/M^2 averaged over the whole earth over 24 hours since 1970 or earlier? |
| |
|
|
quote: Originally posted by CobblyWorlds:
If you increase the amount of IR trapping molecules in the atmosphere, this has the biggest effect in the troposphere. They trap more IR and so reduce the amount of IR going upwards.
Now that is a reduction in the flux of IR going through the stratosphere out into space. So it's a reduction of the energy available in the Stratosphere. Thus the Stratosphere cools.
But these 'IR trapping' capabilities of molecules applies in all directions so not only do you have less IR being released into the stratosphere you have less IR being released into the troposphere also (where the conditions applies). Nevertheless the cooler stratosphere will lead to a cooler troposphere. |
| |
|
|
quote: Originally posted by suricat:However, I didn't propose that it was! Perhaps you may wish to ask Steve_M, or CobblyWorlds about this proposition!
I was being too general in my response and intermixing answers (my time is short too). I realised from earlier posts that your point was to do with ozone and not CO2 - and you made an interesting point with regards to depleted ozone. In fact on giving it some thought, depending on the proportions of the filtering effect of ozone (or lack of) and the additional UV being radiated onto the earth's surface could explain global warming much better than increased CO2 - but this would need to be viewed proportionally and not sexed up as CO2 is. But as I said earlier you cannot discount the troposphere either as the UV would have to pass through it on it's way to the surface. I do not know to what extent the ozone depletion has occurred and the magnitude of the effect on temperature - do you have any links about this? |
| |
|
|
APL,
Yes, the troposphere as a whole will warm, but the upper layers will cool.
Theoretically speaking anything below the "effective radiating layer" will warm, what is above will cool. That layer is in the mid troposphere, the effect is rather like a pivoting, so it's only on the upper reaches that it'll be significant.
The further down into the tropo you go the more the increase of GHGs will dominate over the downward strato flux.
|
| |
|
|
quote: Originally posted by CobblyWorlds:
APL,
Yes, the troposphere as a whole will warm, but the upper layers will cool.
Theoretically speaking anything below the "effective radiating layer" will warm, what is above will cool. That layer is in the mid troposphere, the effect is rather like a pivoting, so it's only on the upper reaches that it'll be significant.
The further down into the tropo you go the more the increase of GHGs will dominate over the downward strato flux.
According to your previous post you state correctly as I understand it that the sun heats up the stratosphere as the MAIN source of heating for the stratosphere. Now you you state that the troposphere holding back the IR is the MAIN reason for the cooling in the stratosphere - do you not see the contradiction in this? In case you genuinely do not see it. What you are stating is that the IR being held back in the troposphere is having a greater cooling effect than that of the sun's heating of the stratosphere. The effects of CO2 are 'observably' not that powerful. |
| |
|
|
APL, you have not got your brain in gear.
"A is cooler than B" is not the same as "A's temperature has reduced whereas B's has increased."
I am not saying that the Stratosphere is cooler than the troposphere, nor am I saying the effect of GHGs overwhelms the solar effect.
Say 2 factors add to create the temperature of an object (or region).
T = Fm + Fn
with numbers...
100 = 90 + 10.
if Fn goes down...
99 = 90 + 9.
So even though Fm has stayed the same when you reduce Fn you reduce T.
|
| |
|
|
APL.
All quiet on the CO2 front, | |
