Comparison of various spaced antenna methods

Spaced Antenna (SA) technique has been used with different VHF and UHF ST/MST radars. Different methods used for horizontal wind measurements and turbulence parameters estimations have been implemented for these different radar systems. They are related to time and frequency domains and result from two kinds of analysis: classical diffraction pattern analysis, [e.g., Spaced Antenna Drift (SAD) and Full Correlation Analysis (FCA), Briggs (1984)] and more recently from a volume scattering model introduced by Doviak, Holloway et al. (1997). The MUTSI (for MU radar Temperature Sheets and Interferometry) experiment data collected on four spaced antennas offer a wide range of atmospheric situations. Actually, the preliminary MUTSI campaign data showed highly stratified and stable layers, whereas the nominal MUTSI data are a more representative sample of turbulent activity. Note that MUTSI data have been collected both in vertical and oblique incidences, for which the algorithms are implemented. The results for these two sets are presented and discussed. Applications on a mini VHF and UHF radars are also presently being studied. In the first paragraph, we give some basic definitions of the various algorithms and present a comparison of the horizontal wind profiles given by these algorithms. We obtain two classical estimates of the wind velocity called "apparent" and "true" velocities. Theoretically, the "true" velocity is corrected from turbulence, perpendicular wind and anisotropy, while "apparent" velocity does not take these effects into account. Validation of the different results with the in-situ measurements is presented in part 2. It is found that the "true" velocity is not always a better estimate than the "apparent" velocity. We will discuss this result.