Efficient dealiasing of Doppler velocities using local environment constraints.

Abstract

A Doppler velocity dealiasing algorithm is described that processes one radial at a time by comparing that radial with a previous radial. This technique has worked reliably on numerous Doppler radar datasets for clear air, thunderstorm, and severe thunderstorm situations. It was also tested on four volume scans from severe weather environments with difficult aliasing problems to determine statistically how well the algorithm performs in a worst case environment. Of some 1.2 million velocities in these severe storms, 0.2% were improperly dealiased, and 93% of those were above 13 km height in the storm-top divergent region where shears were extreme. Every tornado, mesocyclone, gust front, microburst, and storm-top divergent signature was preserved, and could be readily discerned by human analysts. No adverse impact was observed on the signatures, and automated signature detection algorithms would therefore be freed from contamination by velocity aliasing. The velocity dealiasing algorithms would therefore be freed from contamination by velocity aliasing. (A)