An experimental determination of the spectrum of permittivity and air velocity fluctuations along a vertical direction in the troposphere using radio propagation methods

Abstract

An experimental study comprising the measurement of the permittivity spectrum as well as the air velocity spectrum along the vertical direction in the troposphere is presented. It is shown that the scattering-angle dependence of the received power in some 70 per cent of the total number of cases can be approximated by P R ~ ( 1 θ ) exp (− kθ 2). The curve based on the median value of all the sets of observations is of the form P R ~ θ −6.4. The speed of fading increases linearly with the scattering angle which suggests that the fading is caused by multipath transmission via many moving scattering elements. The median ratio of the mean wind velocity normal to the path and the vertical fluctuating velocity is found to be 7.5. The experiment was repeated forty-five times using a 165 km path and fourteen times using a 340 km path. Frequency of radio wave was 6000 Mc/s.