Estimation of Doppler and polarimetric variables for weather radars.

Abstract

A method for estimation of Doppler spectrum and its moments as well as several polarimetric variables on pulsed weather radars is presented. This scheme operates on oversampled echoes in range, that is samples of in-phase and quadrature phase components are taken at a rate several times larger than the reciprocal of the transmitted pulse length. The aforementioned radar variables are estimated by suitably combining weighted averages of these oversampled signals in range with usual processing of samples (spaced at pulse repetition time) at a fixed range location. The weights in range are derived from a whitening transformation, hence, the oversampled signals become uncorrelated and consequently the variance of estimates decreases significantly. Because estimates' errors are inversely proportional to the volume scanning times, it follows that storms can be surveyed much faster than it is possible with current processing methods, or equivalently, for the current volume scanning time, accuracy of estimates can be greatly improved. This massive improvement is achievable at large signal-to-noise ratios (approximately greater than 15 dB).