Simultaneous Measurements of Temperature and Velocity Fluctuations Within Clear Air Turbulence Layers. Analysis of the Estimate of Dissipation Rate by Remote Sensing Techniques

Abstract

Estimates of dissipation rate from remote-sensing techniques measuring the structure parameter C_n² of density turbulent fluctuations assume a relationship between C_n² and the dissipation rate ϵ. In order to obtain a precise test of this relation, in situ observations are of major importance. We present in this paper the first simultaneous in situ measurements of these parameters. The analysis of data shows that the models of turbulence used in the radar literature are not always fully justified and that the estimate of dissipation rate may be underestimated. However, we emphasize that UHF-VHF radars with high vertical resolution offer promising facilities for the observation of clear air turbulence.