85th AMS Annual Meeting

Monday, 10 January 2005
Evaluation of the SZ(8/64) Phase Code Algorithm: Some Operational Considerations
Gregory Meymaris, NCAR, Boulder, CO; and J. Hubbert, S. Ellis, and M. Dixon
Poster PDF (21.8 kB)
The range-velocity ambiguity problem can severely degrade the spatial coverage of the reflectivity, mean radial velocity, and spectrum width estimates from the WSR-88D weather radars. Because the maximum unambiguous range and unambiguous velocity (Nyquist velocity) are inversely proportional, increasing one necessarily decreases the other, causing the choice between range folding and velocity folding. For good radial velocity and spectrum width estimates, velocity folding is deleterious, making short PRT's preferable even though it results in range folding and thus censorship of overlaid echoes. One solution is to phase shift the transmitted pulses using a predetermined pattern called the SZ(8/64) phase code, which allows for the recovery of some weak trip spectral moment estimates (reflectivity, radial velocity, and spectrum width). In this paper, we present a quantitative analysis, comparing legacy WSR-88D spectral moments with those computed using the SZ(8/64) phase code and associated algorithm. The impacts from decreasing the number of pulses per beam, phase noise and phase stability, on the estimators' performance will also be shown.

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