Antarctica usually has a nicely compacted air pressure configuration in its upper troposphere, which keeps jetstream wind velocities strong and a band of streams in place that are tightly wound around the central area shaded in blue. Streams of high-level precipitable water (PW) that are always circling about in areas outside of this band have a hard time breaking through the jets, although some always manage to slip through. The overall arrangement tends to keep the surface beneath the blue zone extremely cold, for lack of greenhouse energy effects, since the surface itself has no liquid water on hand to contribute evaporation. Today, for some reason the usual air pressure pattern has broken down in a couple of places, which should give us an opportunity to see if anything noteworthy happens as a consequence:
Jetstream winds must stay on specific pathways that are marked out for them, and those pathways are constantly being set up in places where isobars keep track of the separation of different pressure levels. One major pathway tracks the outer edge of the blue zone and another the outer fringe of the surrounding narrow green zone, as mapped out for us with great clarity. When these pathways are close together the winds they bear tend to merge and accelerate; otherwise the paths will be split up and their winds will show more weakness. Whenever the isobars get bent completely out of shape, like they are today, the winds must find the way to adjust:
The funny inward twist in the lower left is especially interesting. All jet winds are ordinarily set up to move from west to east. Here the combined stream that is moving along so smoothly at the bottom must suddenly make a sharp bend and reverse direction. Before long there has occurred another reversal, allowing a more regular wind pattern to eventually reform on the other side of the twist. All of these circling jetstream winds carry a certain amount of PW as passengers, which has been picked up along their outer edges. The sharp bends creating this peculiar movement will allow some of that PW to escape into the polar zone interior, like this:
Adding all that PW content to the air above an area that is normally much more exclusive is destined to have an immediate effect on surface air temperatures, simply because there are more photons returning to the surface via the ordinary workings of the greenhouse process. We can see the result that came about in this situation:
The bright red spot in the low part of the anomaly image represents a temperature increase of at least 21C (38F). That’s a true, sensible heat gain, raising temperatures from around -40C to -20. It could not occur without an input of real energy, and there are not many sources available that can supply that much energy, and so quickly. PW does have the strength to qualify, at 10C per double, when quantities are driven sharply higher. The amount of temperature increase we are seeing here, based on the logarithmic principle that applies to all greenhouse effects, means that the normal, or average, PW content of the local atmosphere must have experienced at least a fourfold increase. I would guess that in this case the actual numbers went from about 500 grams, its average for the day, to a full two kilograms. It’s possible! The map shadings give us a few good clues, but having real, hard numbers on hand would be much more convincing. Are they filed away somewhere?
Carl