An Adaptive Dealiasing Method Based on Variational Analysis for Radar Radial Velocities Scanned with Small Nyquist Velocities

Abstract

revious velocity?azimuth display (VAD)-based methods of dealiasing folded radial velocities have relied heavily on the VAD uniform-wind assumption and, thus, can fail when the uniform-wind assumption becomes poor around azimuthal circles in a vertical layer and the Nyquist velocity is small (≤12 m s?1). By using the two-step, alias-robust variational (AR-Var) analysis in place of the alias-robust VAD (AR-VAD) analysis for the reference check, the previous AR-VAD-based dealiasing method is improved to an AR-Var-based dealiasing method adaptively for radar radial velocities scanned with small Nyquist velocities. The method has been tested with severely aliased velocity data scanned by the Oklahoma KTLX radar. The robustness and satisfactory performance of the AR-Var-based dealiasing are exemplified by the results obtained for a severe winter ice storm scanned with the Nyquist velocity reduced to 11.51 m s?1.