POSTSTATISTIC STEERING WIND ESTIMATION IN THE TROPOSPHERE AND LOWER STRATOSPHERE

Poststatistic steering (PSS) techniques are applied for estimating the wind vector. Since spatially separated receivers can be used to synthesize a radar beam in an arbitrary direction, Doppler beam swinging (DBS) techniques can be used in conjunction with PSS to obtain estimates of the wind vector. Data obtained with the middle and upper atmosphere (MU) radar in Japan are used to implement the technique in the troposphere and lower stratosphere at a VHF wavelength. To obtain an accurate estimate of the beam-pointing direction, the synthesized two-way antenna pattern is calculated. Also, the effects of aspect sensitivity on this technique are explored. The mode of operation of the MU radar was alternated between a typical DBS mode and a spatial interferometric (SI) mode, which was used for the PSS technique. Results from the PSS method of obtaining the wind vector are compared to the DBS results, which are assumed to be an accurate representation of the atmospheric wind. This study suggests that aspect sensitivity causes an underestimate of the horizontal wind using PSS. Corrections were made using the aspect sensitivity functions obtained from the DBS experiment and the corrected PSS velocities compare well with the DBS velocities. The vertical velocity estimate using a vertically pointing beam is shown to possess a gravity wave characteristic which is due solely to contamination from the horizontal wind.