The Arctic warm anomaly is still there, even warmer than usual in one area that is showing +17C. The actual temperature taken from the Windy website this morning for that spot is 0C to +1. For comparison, the same source is showing a cold temperature of -60C for a spot about the same distance from the south pole, where the seasonal shift is now well on its way toward summer but not making much headway. Today we will look at the underlying reason for so much discrepancy, for why the regional Arctic anomaly is currently +4.6C in the past three decades and the Antarctic minus 3.7. I’ve never seen a spread that great between these two. Oddly, note that the global average for the entire surface is +0.5C, which is on a perfectly normal trend line. Here is a full picture:
As for the underlying reason, one critical marker is revealed by the layout of jetstream winds in the two regions. In the north the stronger wind jets are badly scrambled, spread widely apart and generally disorganized. In the south the jets are much more compact, forming more of a thick and solid wall. They may be stronger overall, but not greatly. The biggest difference lies in how compact they are, which can only mean the major pathways bearing the speediest jets must be straighter and closer together.
There is one good way to show what makes the difference, and that is by opening up the relevant air pressure map. This map establishes the locations of all the pathways that jetstream winds must track, never being allowed leave their lanes. The differencebetween hemispheres is obvious, and also extreme. I have no way to show what the difference was like at this time of year in years past, especially way, way back, but feel confident it was nothing like what we have this year:
We still have two questions to answer. One is about the effects of the jetstream comparison that may explain how the warm and cold polar temperature anomalies were created. The other is about what may be the cause of the large discrepancy we see above in upper-level air pressure patterns. I think the best answer to the second question is found by taking another look at the very first image, representing extraordinary differences in surface air temperatures. Past letters discuss details that are based on the principle that warm air tends to expand while cold air contracts. The effects from different regional temperatures will be realized all the way to the top of the atmosphere. The first question also has an answer that I have explained in many letters, keyed to the movement of a special kind of water vapor activity. The next map clearly shows the current difference in this activity as it affects the two polar regions:
I can see four water vapor streams that are adding significantly to the vapor content of the atmosphere deep within the polar zone of the north, causing air temperatures to increase from the amplified greenhouse energy effect. Some streams will add more than others on any given day, but nothing seems to stop the total flow input. Similar flows approaching the polar zone in the south are having much less luck getting through to where the driest air is. One final observation needs to be made. The warm surface air mass causing the air pressure pattern and jetstream winds directly above to be weakened in the north is, as a consequence, also on the receiving end of the energy inputs that keep it from cooling, constituting a feedback loop. A similar loop is apparent in the south, but completely reversed. On balance, the average temperature of the entire globe has hardly been affected, at least for the time being, but the physical damage being done to the Arctic is a matter of great concern.
Carl