85th AMS Annual Meeting

Thursday, 13 January 2005: 1:45 PM
Radar range and velocity ambiguity mitigation: Censoring methods for the SZ-1 and SZ-2 phase coding algorithms
Scott M. Ellis, NCAR, Boulder, CO; and M. Dixon, G. Meymaris, S. Torre, and J. C. Hubbert
Poster PDF (1.7 MB)
The NWS will be implementing range and velocity ambiguity mitigation techniques that utilize phase coded transmit waveforms on the WSR-88D radar network beginning in 2005. The initial implementation uses a split-cut strategy including a long range scan for reflectivity and a short range, phase coded scan to obtain the radial velocity and spectrum width measurements at the two lowest elevation angles (referred to as SZ-2). A stand alone technique using a single short range, phase coded scan has been developed for possible implementation at higher elevation angle scans (referred to as SZ-1). These powerful new methods will allow recovery, rather than censoring, of both the stronger and weaker overlaid echoes, substantially reducing the amount of censored Doppler velocity data (purple haze). These new phase coding algorithms cannot recover 100% of the overlaid echo and thus require new censoring methods in order to be successfully deployed. Once the censoring is accomplished the data quality can be further improved by infilling missing values where possible and applying a de-speckling algorithm. This paper will discuss what causes the SZ-1 and SZ-2 algorithms to fail, propose censoring methods for SZ-1 and SZ-2 and show results using real data from diverse weather situations.

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