On the Spaced Antenna and Imaging Doppler Interferometer Techniques>

B. G. W. Vandepeer and I. M. Reid

Abstract

The theory developed by Briggs, [Radio Science 1994] in a companion paper is extended to explain the measurement of a wind velocity equivalent to the spaced antenna apparent wind by IDI-like interferometric analyses. The point is made that the presence of turbulence, or random change in the diffraction pattern on the ground, is directly responsible for the difference between the true and apparent velocities in the spaced antenna analysis, and also for the over-estimation of the wind velocity by the IDI technique. An experiment is conducted to determine whether the ``effective'' scattering points resolved by IDI-like analyses tend to lie upon the azimuth predicted by theory. This is found to be the case, even for unsmoothed cross-spectra for which the theory was not explicitly derived. An averaging mechanism is proposed which may explain the extent to which the unsmoothed experimental data conform to the behaviour predicted by theory.

Status

This paper has been submitted for publication in Radio Science.


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