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DLOC Principles of Meteorological Doppler Radar:
WSR-88D Fundamentals

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Previous Page: Sampling Techniques

VCP Characteristics

The WSR-88D currently employs 9 different Volume Coverage Patterns (VCPs) that involve different sampling techniques. Tables 6-14 contain the various modes of operation for each elevation angle that comprises each VCP. For example, Table 6 lists characteristics of VCP 11 which scans 14 elevation angles in 5 minutes. The total number of rotations is 16 since the 0.5° and 1.5° angles are sampled twice in Split Cut mode. The VCP tables provide the following:

  • Angle: Antenna angle above horizontal
  • AZ Rate: Antenna rotation rate in degrees per second (o/s)
  • Period: Total time required to complete a 360° rotation
  • WF type: Waveform employed; Will be one of the following:
    • CS (Contiguous Surveillance)
    • CD (Contiguous Doppler)
    • B (Batch)
    • CDX (Contiguous Doppler without range unfolding)
    • SZCS (SZ-2 Contiguous Surveillance)
    • SZCD (SZ-2 Continguous Doppler)
  • PRF #: The Pulse Repetition Frequency (PRF) number (1-8)
  • # Pulses: The number of pulses per radial

VCP Animations

In general, a larger number of pulses per radial are used at the lower elevations, transitioning to fewer pulses per radial as the antenna angle increases. Animations of how each VCP employs these characteristics are available. These animations present the PRF #, waveform, Rmax, and Vmax for each elevation angle and give you a relative perspective of antenna rotations per elevation.

Next Page: Pulse Repetition Intervals