It’s mid-summer in Antarctica, a place I have not said much about lately. That goes for the whole hemisphere as well, where climate indicators are completely unlike the current state in the north. Most notably, for many weeks now the daily average temperature anomaly for the SH has been stuck at around the level where you see it today, slightly negative compared to 30 years ago, as recorded below the next image. The same is true in the north except at the other extreme, leaving the globe’s average about where it “belongs,” in some respects.
Southern Australia is getting plenty of relief from the horrors of a year ago, which can be attributed to a major decline in precipitable water (PW) in its atmosphere. The 10-12kg value you can see on the next image is less than half of what we are seeing in the northern half of the continent, where the current anomaly is a few degrees on the warm side v. -8-10C in the south. The whole PW map will have some other interesting things to tell us, regarding the same sequence of cause-and-effect phenomena that was discussed in yesterday’s letter.
Now focus on the general size and shape of the entire area, including gray parts, contained within the rim of light-brown shading. This zone represents everything of low-value PW in the SH today, surrounded by higher values for almost all territory farther north. Notice how well the overall size and shape of this zone corresponds with the zone of cool-type anomalies in the top image. Could the coincidence be accidental? If not, what might be the nature of the connection? Is one a cause of the other? We can’t stop here, but will instead move on over to the jetstream map to see if there are any other size-and-shape coincidences to ponder about.
Given this view, does it seem possible that the way jetstream winds are set up may in fact be having considerable control over potential quantities of PW that otherwise might be entering the area of enclosure? That thought immediately raises questions about the nature and disposition of the PW presence. Where does it come from, why should it even be getting involved with jetstreams in the first place, and why should we think there are quantities that may have a kind of intent to visit Antarctica more closely if only the jetstreams were not there to stop them? Which reminds me, why are the jetstreams there? That calls for another map:
The shape could remind one of a fleur-de-lis, suggesting a cosmic connection, but let’s drop that idea. Let’s also drop any idea that the jetstream winds are causing the air pressure pattern be set up the way we see it. Instead, one must always expect that air pressure isobars will govern the placement of winds up high as well as they do at the surface. Finally, are there any more maps that might give us a clue as to how the shape and size of the air pressure configuration has itself been determined? When I started writing today I was not expecting to add a mention of anything of the sort, but there has been a surprise. In general, my best guess would be only that the pattern would probably not have such a nice compact shape, unlike related images we are now seeing in the north, unless it were centered over an entire surface below that was relatively cold and also revealed relatively uniform borders surrounding the coldest parts. So I went ahead and made a quick check of today’s real temperature map. Here is what I found:
Carl