The interior is. And one of the reasons for that is that outer areas may not have any condensation nuclei, it DOES get cold enough quite easily (especially if you go up a few hundred feet) to get spontaneous formation.

Another reason for the dryness is that the air circulates around the antartic. But as the temperature differential gets bigger, you will get more air breaking the barrier at the pole.

Both of which show how antartic land ice can expand when it warms…

Mark // July 13, 2009 at 4:33 pm — Antarctica is by far the driest continent. For whatever reason.

Yes.

Have you read about the many different known biogeochemical cycles? ….. History of Global Warming (Spencer Weart) · IPCC (Intergovernmental Panel on …
tamino.wordpress.com/2008/08/08/yet-more-co2/

However, an air temp of less than -30C ensures that there will be spontaneous droplet formation.

If I remember my physical geography course correctly…

Why these two phenomenon? Water absorbs CO[sub]2[/sub] and the colder the water, the greater the absorption. Also, the purity of the water has a bearing. The greater the water purity, the greater the absorption of CO[sub]2[/sub] and CO[sub]2[/sub] just happens to be the first atmospheric gas to diffuse into pure water.

Rain precipitate is fairly pure water and absorbs a lot of CO[sub]2[/sub]. Thus, a large part of the CO[sub]2[/sub] in the atmosphere is returned to the Earth’s surface water by rain and stored in the subterranean water-table and ocean by systems within the hydrological cycle (where other processes also take place).

This enables us to look at this as a catalytic reaction scenario that grasps for the catalyst (CO[sub]2[/sub]) when other attractors do the same (that is, grasp for CO[sub]2[/sub] to use within their own system of catalysis, and an obvious example of another system would be the photosynthesis system employed by flora).

So, when average global temps are low there is more competition for CO[sub]2[/sub] between attractors because the hydrological cycle’s sink is greater, and I would expect this to cause a reduction in atmospheric PPM of CO[sub]2[/sub].

We have presently just passed the warm maximum of a Milankovich cycle, but don’t confuse this with our current sunspot minimum. This also doesn’t take fossil fuel combustion into account.

Best regards, suricat.

[Response: Bear in mind that Milankovitch forcing is achingly slow compared to most climate forcings operating now. The *fastest* Milankovitch cycle is about 20,000 years.]

Dimly remembering my cloud physics lectures 34 years ago, cloud condensation nuclei are common enough everywhere to limit the relative humidity that develops in a cloud before condensation starts to no more than a percent (or less, a small number anyway). However the CCN concentration does have an effect on the number of droplets that develops, and therefore on the size to which they ultimately grow, and therefore on the radiative properties of the clouds. But it remains true that, regardless of CCN levels, condensation will occur when the relative humidity of a parcel of air exceeds (slightly more than) 100%.

Hank Roberts says:
“Tamino, I hope you get an answer and more from Dr. Held; have you tried email in case he doesn’t see the inline response you made?”

I think Dr. Held answered here by saying that we have a good seasonal and long-term picture of upper water vapor, but “we shouldn’t expect the agreement between model and observations in the upper troposphere to be as beautiful as near the surface” (I guess, that short-term variability is more difficult in the upper troposphere).