SPACED ANTENNA ANALYSIS OF ATMOSPHERIC RADAR BACKSCATTER MODEL DATA

A simple computer model of atmospheric radar backscatter is used to investigate and compare various spaced antenna (SA) techniques, including the full correlation analysis (FCA) and a number of imaging interferometry techniques. The results illustrate that the FCA true velocity proves to be an excellent estimate of the model input velocity for all magnitudes of model turbulent motions. On the other hand, the interferometric velocities increase as the magnitude of the turbulent motions are increased, providing a poor estimate of the model input velocity for large turbulent motion magnitudes. Maps illustrating the interferometry-estimated scattering positions superimposed upon the actual model scatterer positions reveal the estimated positions to be inaccurate. The estimated positions are shown to approach the zenith as the magnitude of the turbulent motions increases confirming the volume scatter derived suggestions of Briggs (1995). Furthermore, the estimated positions have a preferred azimuth angle agreeing with volume scatter derived suggestions. The effects of receiver noise upon the interferometric techniques are investigated, revealing an effect analogous to the FCA triangle size effect whereby the estimated velocity decreases with increasing noise level. The effects of the thresholds used to preclude individual Doppler frequencies from the analyses are illustrated. The results are in excellent agreement with the experimental results obtained in a number of different studies.