Mechanisms of Clear Air Turbulence

Abstract

Clear air turbulence (CAT) usually possesses a dominant or characteristic length scale: it occurs in layers possessing a thickness and it lasts for a certain time and produces changes in velocity and temperature profiles in the air in which it occurs. Some of that statement is supposition, and some is based on observations from aircraft, but whether they are correct for all CAT it is certain that we are not going to be able to predict these things. Our observations are crude because the gradients measured by radio sondes are only rough on the scale of the turbulence, and the horizontal spacing of our observations is such that we are unlikely to sample air whose o flow is just about to break down into CAT.

Presented by Dr. Frank W. Warren, Imperial College, Lodon.