Here is my “map of the day,” representing a global measure of the altitude of a single amount of air pressure, 500 hPa (or mb). This measure is roughly half as strong as the average amount of pressure for all locations as measured or determined at sea level alone, thus its high altitude. The numbers are read in “dam,” or meters times ten. The 500 level is generally lowest in both of the polar areas, highest at around 20 degrees of latitude and a little lower than that along the equator. What we see on this map is a great divergence between the two hemispheres with respect to the upper latitudes, a divergence that has been growing rapidly in just the last few weeks and days. I am not sure what this map looked like one year ago, or in any year at mid-May, but I do know there is a lot of unusual activity taking place in the north that is resulting in substantial warming anomalies.
One conclusion you can draw from this map is that practically the entire 500 level in the north is rising to a higher level of altitude, by an average of 400 meters or so. Close to the north pole the rise is even greater, around 600 meters, giving that area a bulge effect over its surroundings. We see all this happening at a gross altitude of less than four miles, which is probably lower than the level or levels where jetstreams are in play. I will assume that air pressure patterns associated with 400 or 300hPa will exist at higher altitudes than 500, and will look pretty much the same, and that somewhere within that space we would most likely find the presence of jetstream winds. Moreover, as indicated in many ways on other weather maps, we can feel pretty sure that massive streams of precipitable water are cruising around at the same altitude as the jetstream winds, and are having their courses altered by the strength of the latter.
Another thing we know from the weather maps, as pointed out in previous letters, is that jet-producing wind currents have pathways that are well-defined by their location within the overall pattern set up by high-altitude air pressure. We also know that there are separate pathways followed by three major currents of these jet-producing winds, normally spaced out in a concentric type of relationship but otherwise being somewhat irregular. (See CL#1657, April 15.) With all of the above information in hand, we see good reasons for asking some questions. One is simply, how thick, vertically, in meters, are most jetstream winds? If they are moving higher (or lower) by 400 meters or more, how might that amount of change affect their relationship with the water streams that arrive independently and are in play in the same general space?
Looking again at the map above, there are more questions, especially with respect to how substantial changes in the configuration of jetstream wind pathways, as now is seen to be happening, might affect the courses taken by airborne water streams as they keep pushing their way toward the poles. Or, what happens when two of the three main jetstream pathways are broken into numerous separated pieces instead of being singular entities? Doesn’t that give the water streams yet more room to maneuver? And what about wind speeds? Have they weakened any? In this next chart we see how water streams are in fact penetrating deep into the heart of the polar Arctic zone right now, as opposed to the more stable situation in the south:
Next, the current temperature anomaly result. One thing to keep in mind is that high-flying streams of water, mostly made of vapor, are not carrying any heat with them as they fly. Nothing is being deposited from above that would cause these massive anomalies: All of the added heat is created as a result of the greenhouse effect produced by the presence of so much water vapor, hovering over a region that produces so little of its own at the surface. (The Arctic region, by the way, is still mostly covered with ice.) Once more, the primary rule: Whenever the water vapor column over a specific region has doubled in weight, and there are no offsetting factors, the air temperature at the surface below will have increased by 10 degrees C. And so it will be for the next double, and the next, and so on. Such gains appear very quickly, and they will disappear just as quickly once the vapor has declined, which means constant replenishment is a standard requirement for any heating to be sustained.
Carl