TITLE

Measure of temperature profiles by radio-acoustic remote sensing technics : theoretical and experimental study. Thèse de l'Université Blaise Pascal; spécialité : Physique de l'Atmosphère, Clermont-Ferrand, mai 1994, 178 p. (in french).

SUMMARY

The aim of this work is a theoretical study of the RASS (Radio Acoustic Sounding System) technics which allows the measurement the speed of propagation of waves sound emitted by an appropriated sound transmitter in order to deduce a temperature profile. This aim also includes the feasibility of this technics using the LaMP/OPGC wind profiler radar

The first part is devoted to recalls of Atmospheric Acoustics, to the description of the RASS method, of its history, of its performances and of its limitations.

The second part treats the physics of the measurement by a RAS System. A numerical model is developed in order to study the influences of temperature, wind and turbulence fields on the performances of the RASS system. The model shows that the performances of RASS method (height) are essentially limited by the entrainment of the sound waves by the wind. In this part, the equation of RASS is established which gives the power of the backscattered radar signal depending on different radioacoustic parameters.

The third part of this study concerns the instrumental and the experimental aspects. After describing the acoustic set up, the modifications which have been made on the LaMP/OPGC wind profiler radar, in order to adapt it to the RASS methodology, are presented. Finally, the obtained experimental results are analysed. From an observation case of RASS echoes, the temperature and the RASS echo power profiles are determined. These results allow the establishment of RASS feasibility.

Key words

Active remote sensing, RASS, wind profiler radar, remote measurement of temperature, sound propagation in the air, radioacoustic sounding, atmospheric acoustics.

Y.Pointin

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