PRF
Pulse Repetition Frequency measured in Hz (pulses per second). When measuring
PRF, a pulse contains transmit, receive, and dead time phases. PRF aects range
folding and velocity folding detection. Normal PRF values for Doppler radars are up to
1000 Hz. Vaisala radars generally operate around 400-700 Hz. In Vaisala IRIS
products, PRF limits the area displayed in radar images and the maximum measurable
wind speed.
PRT
Pulse Repetition Time
PhiDP
Dierential Propagational Phase Shift. The phase dierence between the HH and VV
(co-polarized) channels of a polarization radar. It is calculated by taking the argument
of the covariance of these two channels. The dierential phase increases with range
more rapidly in regions of heavy rain.
PhiH or PHIV
The average phase dierence between the co- and cross-polar channels for a dual
channel polarization radar operating in fixed or switching mode. The H and V notation
indicates the transmit polarization.
Products
Calculated from ingest files that are collected during the execution of a TASK.
Products may be pictures, data or text. For example, PPI and RHI.
Protected areas
Regions around the radar (such as runway locations) for which special alerts are
required based on detected radar data.
Pulse
A short burst transmission signal sent by the radar, used to measure the weather
activity in atmosphere. The reflection measurements from a pulse are sorted into bins.
See also Bin (page 103).
RAW product
Spherical coordinate data product obtained directly from the raw ingest data. The
data are stored in compressed format so they can be recorded on tape or sent to a
workstation for further processing.
RHI product
Range Height Indicator. This is a classic radar scan geometry used in IRIS where the
azimuth is held constant and the antenna is scanned in elevation. The resulting picture
is a two-dimensional vertical slice through the atmosphere.
RVP900
Digital IF Receiver and Signal Processor. A floating-point programmable signal
processor which directly samples the IF signal from a radar.
Rainfall Rate (R)
Rate of accumulation of precipitation in units of mm/hour. For snow, this is usually
refers to the liquid equivalent.
Range folding
Radar signal echoes from outside the radar maximum range that are incorrectly
displayed within the radar measurement area. Also called range aliasing.
Glossary
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