Real climate science revision. From elsewhere:
See you aren’t going to get it because all you do is get your smartass comebacks from Coby Beck and Realclimate.
Because you are used to averaging everything you don’t get the context. When these guys go for the radiative heat balance they average out all the real information.
Water vapour is actually proof of refrigeration. And its not water vapour alone that does the job. Its the dual act of water vapour and microscopic liquid airborne water. Remember that phrase. If you use the phrase “droplets” you will never click.
Supposing we are talking mid lattitude ocean. Summer. A hot day. A parcel of water vapour saturated air comes off the ocean since the wind is whipping along. This has a massive refrigeration effect. The water vapour is blocking huge amounts of incoming and outgoing at the same time. Its a net cooler in this context. I know its a warmer in other contexts so don’t jump ahead. There is no doubt its a net cooler in the situation described. Both for its refrigerant effect on the ocean. And its buoyancy. Since the surrounding air is dry it takes all that energy straight up to mid-troposphere. Thats a cooler if ever there was one.
Contrast this to the ocean at the equator. Much the same story. Only this time there is not much buoyancy. Now the water vapour may go up some. But we get a situation where much of the water vapour hangs out low down. Continually phase changing. Releasing that refrigerant energy via the phase change back to water. But only microscopic airborne liquid water. Not droplets. There is no buoyancy in your otherworldly model.
Now consider the microscopic airborne liquid water. It is like no gas for warming. It is 100-1000 times the weight of the molecules surrounding it. It can be grabbing energy from above and below. It can be sinking when its warmer than the surrounding molecules. There is really not much in the way of greenhouse effect. Its really all about water phase-change in mid-air.
Thats the secret of the globe heating up. Essentially it is the expansion of the tropical zone pushing the other zones north and south and up the mountains. The tropical zone is the zone where water-vapour saturated parcels of air lack special buoyancy.
FURTHER NOTE: ABSORPTION OR SCATTERING.
If the above is true why doesn’t the water vapour keep heating up and continue to get more and more buoyant as it gets higher? How is it that the water vapour ever manages to cool enough to turn into droplets so as to form clouds. There are quite a few reasons going into this story and so I’ll concentrate on the neglected one. You see what we are told are greenhouse absorption spectrum, when looking at an individual molecule, are really greenhouse scattering spectrum. Yes its true that in the totality of the interactions most of that spectrum of light will eventually be absorbed and turned into thermal energy. The molecules scatter most of this, and absorb some of this. In the final analysis the totality of the atmosphere will absorb these wavelengths its true.
But there is a trick to this. The higher is the air pressure the more effectively the air can absorb rather than simply scatter the wavelength regions. So when the parcel of water vapour saturated air first comes off the ocean it is scattering IR light from above and below. But it can absorb quite a bit of it as well as just scatter it. As it gets higher and higher, though its absorbed awesome amounts of energy, the parcel of air has expanded (((((( expansion leads itself to cooling)))) and because that parcel of air has less air pressure it is now almost only scattering the light and no longer absorbing hardly any of it and turning it into thermal energy. Otherwise it would go on rising to the top of the stratosphere. Its important to understand the role of the air pressure in determining how effective the air is able to absorb and convert this light, rather than merely scatter it.
Now why would that be??? Well I won’t go right into it. But I’ll just give you a working model based on somebody else’s quote. It will do fine for now:
“Photons HAVE wavelengths.
The CO2 (and all the other greenhouse gases) re-emits everything it has absorbed if it hasn’t lost/spread the energy through collisions with surrounding molecules first. And this re-emission happens incredibly fast. See my post above about Downwelling Longwave Radiation. So it doesn’t have time to move much of anywhere before the energy re-balances.”
What Glen is describing is the following model of things. The photon hits the molecule. This causes an electron to jump up to a higher “orbital” But then the electron jumps back down and emits another photon but in a random direction. There is a time delay. Its not straight scattering. But the wavelength is unchanged. But what if we have the following sequence of events.
1. Photon hits molecule. 2. Molecule absorbs photon and this causes electron to jump up to a higher orbital 3. Molecule hits other molecule prior to the electron releasing an identical photon.
Bear in mind I’m not buying this model except as a working model. And it works for this purpose. The point is that the molecules will scatter light in their scattering-absorption region unless interrupted by another molecule in the middle of this process. And what makes it MORE LIKELY that any molecule will be so interrupted? Air pressure of course. It is air pressure that makes the gases more effective at absorbing and converting the light into thermal energy. Understanding the effects of air pressure is a massive part of understanding climate.