Abstract
It is shown that, so far as can be judged from present data, there is no appreciable net flow of polar air in the lower troposphere (i. e., between about 1 and 4 km.) towards the subβtropical antiβ cyclone.
This supports the view of Dr. Jeffreys, namely, that the exchange of air between different latitudes, required to maintain the angular momentum of the zone of W. winds against friction, is carried out entirely by currents lying side by side, and not one above the other.
It is shown that if this exchange of air could be treated by the methods developed in the classical theory of turbulence, cyclones and anticyclones being regarded as eddies in the general circulation, then the supply of angular momentum into the westerly zone would be enormously greater than what is required. It is thought that the angular momentum does not diffuse in this way, owing to the large size of cyclones and anticyclones (this is probably to some extent true also of the diffusion of heat and moisture).
The fundamental problem is the relation of the individual cyclone to the general circulation, and this has not yet been solved. Some empirical facts are mentioned which may prove useful to future investigators of the subject.