The jetstream study we did yesterday has important practical applications for anyone interested in knowing how temperature anomalies are formed. Today I will offer an example, with reference to a major warm anomaly that has appeared in central Russia. The square shape of the border on two sides makes it an unusually convenient one to work with:
We’ll start with a quick look at the map of air pressure configuration in the upper atmosphere because that will tell us exactly where the basic jetstream pathways are now located. We also might get some ideas about where to expect the strongest jet winds to be found and where there may be some that are effective even if they lack much if any visibility on the map.
Here is what we actually get. I am impressed with how strong the jets are along the red zone pathway, apart from the weakness that appears where the pathway becomes so irregular directly to the south of Manchuria. Higher up, we know there should be a low-velocity pathway all along the edge of the green zone where a narrow piece of it has turned and made a dip to the south as far as Kazakhstan. We can see a visible jet going part of the way but then not quite strong enough to show up over the entire distance, yet possibly still effective as a container.
These images provide evidence that the anomaly has literally been walled off on at least two of its sides, and that somehow the event should be connected to the presence of jetstream winds because the winds are positioned so exactly in the places where the walling takes place. A search for that connection inexorably leads us back to a basic idea, often expressed in these letters, that water vapor-must be involved. Because of its powerful greenhouse capability water vapor of sufficient quantity is the only viable source of energy capable of producing such a large temperature increase on such short notice, and large amounts of it are known to exist at high altitudes. In this case there would need to be evidence of true physical connection between the vapors doing the heating and the wind jets apparently in control of the size and shape of the area being heated. Let’s go to the Precipitable Water map and see if that’s the case here:
A massive amount of precipitable water (PWat) is plainly visible over the entire area of the warm anomaly, which is not too surprising. What really makes it interesting is how well-defined the shape of this mass is on two of its sides, both positioned in the very place that was formed when a jetstream wind is seen to have turned a square corner. The connection is simply unmistakable. A couple of things need to be pointed out here. One is that the PWat measures on this map include the weight of every bit of water vapor from the ground up plus all of the products of condensation produced by vapor that remain in the air column. Nearly all of it must have originated in a far-off body of warm water and then carried through the air to the continental interior, until being stopped for whatever reason. A considerable part of the total had to be transported at a high altitude in order to be stopped by jetstream winds, as we have seen. Since no actual figures of the breakdown are available, how large an amount is that likely to be? One can make an estimate simply by observing how large the PWat measurement is on each side of the lines of stoppage. It looks to me as if one is about double the other. This could fully account for the size of the anomaly, which peaks around 10C.
Carl