|You have no proof an atmosphere of 100% oxygen is not as effective as the current atmosphere in trapping heat24-09-2016 01:18|
|Tai Hai Chen★★★★☆
|As this chart shows, it only depends on pressure to determine temperature. That's why higher elevation is cooler lower elevation is warmer. |
For example, a 34% increase in pressure going from 8000 feet to sea level increases temperature by more than 15 C.
Edited on 24-09-2016 01:29
|Correlation =/= causation, THC.|
|Tai Hai Chen★★★★☆
More pressure is because of more air. More air is more conduction. More conduction is more heat trapping. More pressure causes more temperature.
|1. "more pressure is because of more air"|
Trivial. More pressure implies that all else equal, there are more molecules present per unit volume of gas. So more pressure means more air.
2. "more air is more conduction"
I will agree that denser air conducts heat better, although since it's a very bad conductor this doesn't change much.
3. "more conduction is more heat trapping"
Aaand this statement makes no sense. The conductive properties of a material are completely different from its specific heat - by "heat trapping", do you mean how much energy is required to raise its temperature (equivalent to how much energy is released when it cools)? Except through heat capacity and emissivity, materials cannot "trap" heat, and even then, only in the sense of a reduction in outflow rate. (And technically you mean energy trapping.) So no, the increased pressure at the bottom of the atmosphere does not cause the greater temperature.
And besides, didn't Surface or IB or somebody give you an image like this?
Pressure isn't even correlated with temperature. How can you argue that it causes it?
jwoodward48 wrote:Pressure isn't even correlated with temperature. How can you argue that it causes it?
Yes, temperature and pressure are related by the ideal gas law.
Question: The peak of Mt Whitney and the basin of Death Valley are mere miles apart geographically. The peak is substantially colder than the basin even though the peak is technically about three miles closer to the sun.
Sea level varies from place to place in the world - keepit
Clouds don't trap heat. Clouds block cold. - Spongy Iris
Printing dollars to pay debt doesn't increase the number of dollars. - keepit
If Venus were a black body it would have a much much lower temperature than what we found there.- tmiddles
Ah the "Valid Data" myth of ITN/IBD. - tmiddles
Ceist - I couldn't agree with you more. But when money and religion are involved, and there are people who value them above all else, then the lies begin. - trafn
You are completely misunderstanding their use of the word "accumulation"! - Climate Scientist.
The Stefan-Boltzman equation doesn't come up with the correct temperature if greenhouse gases are not considered - Hank
:*sigh* Not the "raw data" crap. - Leafsdude
IB STILL hasn't explained what Planck's Law means. Just more hand waving that it applies to everything and more asserting that the greenhouse effect 'violates' it.- Ceist
|Well, of course the Ideal Gas Law states that compressing a gas will heat it up, but that's beside the point. The graph of temperatures in the atmosphere shows that there's no correlation IN THE ATMOSPHERE, when looking at the big picture.|
In the troposphere, there is definitely a correlation. Outside the troposphere, there isn't.
|Into the Night★★★★★
You will notice the troposphere and the mesosphere follow the idea of the Ideal gas law. In other words, temperature decreases with pressure.
Why the anomaly for the stratosphere and the thermosphere?
The stratosphere is where our ozone layer resides. This molecule, O3, requires energy from somewhere to make it from the usual oxygen, O2. That energy comes in the form of UV-B energy from the sun. The result is that most UV-B is eliminated from reaching the surface.
The O3 molecule doesn't just sit there. It floats around, including upward. If it gets high enough, the harsher UV-C energy tears it down again and it becomes O2. This absorbs the UV-C energy so it doesn't get even down to mess with formation in the lower part of the stratosphere.
O3 can self decompose into O2 on it's own.
Either way of ozone destruction releases energy in the form of heat. Since the combined effect of self destruction and destruction by UV-C is at the top of the stratosphere, that is warmed considerably.
The atmosphere is warmed by convection and conduction from the surface (as well as a certain amount of direct radiation). This warm air rises, cooling as it goes, due to the ideal gas law. in action. It is losing pressure.
At the same time, the hot area of the stratosphere is conducting heat downward, dispersing energy as it goes. The result is a region of one of the coldest places in our atmosphere. The 'gap', which we call the tropopause. That is where our jets like to fly. Cold air performs best in jet engines, and the low pressure means less drag. This is the area of best fuel efficiency.
Air in the troposphere also descends (to replace that air that rose). This cooler air will warm again as it descends, just like it cooled as it rose. It will not warm as much as it was before, however since it has been losing energy overall by radiation while moving around. The lower it descends, the warmer it gets. This, combined with continue heating by the surface, means that low elevations areas like Death Valley are quite a bit warmer than Las Vegas, which is nearby.
The Parrot Killer
|Thanks! I knew a bit about the atmosphere, but barring the thermosphere, I didn't know what caused the temperature weirdness on the graphs.|
BTW, is THC correct? It doesn't seem that way - if atmospheric composition can't affect temperature, why should atmospheric pressure?
|Into the Night★★★★★
In some ways he is and in some ways he isn't. The temperature profile of the atmosphere you referenced to shows where his statement is most wrong.
Where there is vertical air movement (mostly the troposphere, since the thermosphere is barely there at all), you will have pressure changes in air.
Next time you see a big piling up cumulonimbus, take a good look at it. Fortunately, these storms often suck up moisture from around them and often stand alone.
The entire storm is a great visible example of hot air rising quickly.
Under the storm, air is hot. It has been warmed by the surface. At the same time the air above it is colder than usual. This produces what the meteorologists call 'unstable' air. The temperature profile of the air is dropping faster than normal (what the meteorologist calls the adiabatic rate). This air contains water vapor.
Once something starts the air moving upward (a hot spot on the surface, a mountain catching the wind and blowing it upward, anything), that hot air wants to keep moving upward, faster and faster, like a hot air balloon that's too hot.
As the air rises, it cools. That's the pressure drop in action.
At the point the air is cooled enough, it can't hold that much water vapor anymore and the water vapor condenses out and becomes visible. It becomes a cloud. That will happen at a fairly constant altitude.
Looking at the cloud, you will notice the bottom of it is flat. That's the condensation point. That's where humidity reaches 100% and the dropping temperature reaches the dew point of the air.
That air continues to rise, taking water (not water vapor) with it. It will rise right out of the top of the cloud, leaving the last of the moisture behind it. The top of the cloud is lumpy. If you stand and watch it, you can actually see the moisture moving up and out. The billowing effect at the top.
If it rises high enough, that water will turn to ice. Then something truly magic happens.
The top of the cloud starts to look fluffy, with indistinct edges. It begins to blow in the direction the storm is moving. Since ice is lighter and more easily blown than water, you get the appearance of an anvil at the top. Notice how the anvil is somewhat indistinct at it's edges. That means it's ice.
That ice develops a downward current (a downdraft) right in the front edge of the storm.
Now you have strong updrafts and strong downdrafts right next to each other. Like rubbing a balloon on glass, that conflicting air starts stripping electrons off. They tend to move downward, while the updraft tends to be devoid of electrons. Positive ions move up, while electrons move down.
Eventually the difference in charge overcomes the electrical resistance of the air (which is a pretty good insulator) and punches through. The result is a spark. A really, really big spark. We call it lightning. It may go for another cloud, within itself, or strike the ground which is positive compared to all those electrons piled up in the bottom of the cloud.
These conflicting updrafts and downdrafts also disturb the fine droplets of water in the cloud. They start to clump together. They get heavy enough to fall...rain (or hail if the top of the cloud is cold enough and the downdraft violent enough).
Eventually the cloud beats itself up and it dissipates away. This usually takes about 20 minutes to an hour.
The best way to see convection for what it is, and a great way to get rid of surface heat.
The Parrot Killer
|Into the Night★★★★★
|Remember how I described ozone (O3)? All you have to do to make the stuff is to take oxygen (O2) and shove energy into it. It really doesn't matter how. It can be heat, light, electricity, anything.|
In that storm I just described, ozone is created. It is the result of all that electron stripping activity I described, producing ions. Some of those ions are oxygen and they reform info ozone.
When that ozone hits the downdraft in front of the storm, it will be taken downward toward the surface. At the surface, the downdraft spreads out in all directions (it has nowhere else to go!), but will tend to get blown forward, like the anvil at the top.
The result is that fresh rain smell of an approaching storm. That odor is ozone. Like any ozone, it won't hang around, but self destruct back into oxygen on its own after awhile.
|RE: You have no proof an atmosphere of 100% oxygen is not as effective as the current atmosphere in trapping25-09-2016 04:17|
|THC: But pressure itself doesn't create extra energy. Compressing gives a one-time bit of energy. The mere existence of pressure does nothing.
Edited on 25-09-2016 04:17
|RE: You have no proof an atmosphere of 100% oxygen is not as effective as the current atmosphere in trapping25-09-2016 09:46|
|Into the Night★★★★★
It actually doesn't even do that.
It takes energy to compress air. Compressed air is heated. You get energy right back out again, but less than it took to compress the air in the first place (no compressor is perfect).
Releasing pressure is like releasing pressure on a spring. You get some of it back. To get back as much as you put in compressing it, you have to suck the heat back out too.
This is how a refrigerator works.
A pump puts energy into compressing a gas until it's a liquid. That makes it nice and hot.
Put the moving liquid through a radiator and let it cool off to room temperature (the coils in the back of your refrigerator). Once cooled off, stuff it through a tiny orifice. The pressure drops on the other side. You just took it from room temperature to freezing cold.
Run the cold gas (now at low pressure) through a radiator, but instead of cooling off, it's now taking heat from inside your box.
Gather it up again and pump it up again. Lather, Rinse, Repeat.
Whether the energy is in the form of heat (kinetic energy), or in the form of pressure (potential energy). It's still the same energy just moving back and forth between kinetic and potential energy.
The Parrot Killer
Edited on 25-09-2016 09:48
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