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Erl Happs comment

Quote:The cloud data may be unreliable. But cooling on the margins of Antarctica and the increase in Antarctic sea ice is well documented.

I am going to focus on the cause as I see it and describe it at
Over the last 70 years there has been a falling away in surface pressure in high southern latitudes as polar cyclones have increased in intensity.

Polar cyclones originate in the contrast in air density between the 300hPa and 50hPa pressure level due to the difference in the absorption of long wave infrared between ozone rich air on the outside of the chain of polar cyclones (vortex if you prefer) and the inside (the polar cap side where mesosphere air, congenitally deficient in ozone descends and cools the atmosphere in winter under a regime of very high surface pressure. It is here that the ozone hole manifests in spring heightening the difference in density across the vortex and pushing surface pressure at 60-70° south, where these polar cyclones form, to its seasonal minimum in October.)

The loss of atmospheric mass (reduced surface pressure) in high southern latitudes results in an increase in atmospheric mass (increased surface pressure) across the rest of the globe but nowhere more than in the region of the high pressure cells that circulate west to east centered on about 30° south.

The upshot is an increase in the velocity of the surface winds that blow from 30° south to 60° south latitude. These winds include streams of warm wet air moving from the tropics towards high latitudes. Over the last 70 years the surface pressure differential between these latitudes has doubled.

Cloud forms in abundance where the warm moist air meets cold dense air in high latitudes.
The enhanced strength of the north to south flow has driven the cloud zone southwards. Result is reduced cloud north of about 45° south and increased cloud density south of that latitude. Hence warming north of this latitude and cooling south of that same latitude. The actual latitude will vary according to longitude and the configuration of the continents so don’t be picky.
The decline in surface pressure at 60-70° south is reversible.It will occur as the southern stratosphere continues to cool. Temperature of the southern stratosphere peaked in the late 1970’s and cooling cut in on a month by month basis over the interval since that time. Until recently, there has been no decline in the month of October.

In the last few years we have seen a fall in both the AO, index and the AAO index indicating rising surface pressure in high latitudes in both hemispheres. This is the result of of a falling away in the intensity of Polar Cyclones as the partial pressure of ozone on the equatorial side of the ‘polar vortex’ falls away.

Partial pressure of ozone depends on the rate of intake of mesospheric air into the stratosphere over the pole. Rate of intake corresponds with the speed of the ‘zonal wind’ that flows west to east in the winter stratosphere. It is known that the zonal wind fluctuates in its intensity with geomagnetic activity due to the solar wind. It is in this way that the sun modifies the strength and the direction of the planetary winds and more particularly the synoptic situation as meteorologists and TV weather commentators observe it on a day to day basis.

Climatology is very weak in its understanding of processes in high latitudes. To help you understand the process imagine a set of gigantic motorized egg beaters or paint stirrers lifting the air between an elevation of 300 hPa and 50 hPa at 60-70° south. This is the source of the chain of polar cyclones that surround the Antarctic continent. These cyclones are energised by long wave radiation from the Earth itself. That radiation is available at all elevations. Ozone increases in concentration in winter on one side of these mixing zones and falls away on the other side. In the polar night there is no sunlight to account for the temperature differences.No heating effect from short wave radiation. All the heating effect is from long wave at 9-10um and its superabundant.

The polar vortex is not a wall. It’s a mixing zone. There is no mixing zone so vigorous anywhere on the Earth. Central pressure in a polar cyclone falls to 950hPa equivalent to core pressure in a cat 4 tropical cyclone. There is no release of latent heat to drive the polar cyclone. Try as it might the mixing process never runs to completion.

No, this cooling in high latitudes has nothing to do with Hadley cell dynamics. That’s the tail. The dog is elsewhere.
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