Vaisala IRIS - Table 7 Algorithms for Rain Alg

Data type Description
ZV, ZE Vertical (HV Enhanced) Reflectivity
Total reflectivity from the vertical polarization channel (ZV) and combination
of the horizontal and vertical channel (ZE). Corrected for ground clutter.
ZC
Corrected Reflectivity
Same as Z, but corrected for attenuation and beam blockage eects.
ZDR
Dierential Reflectivity
The ratio of SNR in the horizontal channel to the SNR in the vertical channel.
Positive values indicate more prominent horizontal echoes and negative
values more prominent vertical echoes. Larger hydrometeor sizes are usually
identified by high positive ZDR values.
ZDRC
Corrected Dierential Reflectivity
Same as ZDR, but corrected for attenuation and beam blockage eects.
Product Maximum Range
If you select a custom Map Projection Name (other than <NONE>), you cannot configure
this field in the product output menu. This is because the maximum range is determined
by the projection configuration.
See Configuring Map Projections (page 19).
This is the maximum range configured for the product, which must be less than or equal to
the data range. The maximum range is the range in the E-W / N-S direction centered on the
radar. This means that the range to the corners of the resulting display is greater.
Rain Alg
You can choose the algorithm for rainfall estimation from a selection that varies from
traditional Z-R relation R(Z) to advanced algorithms for rainfall estimation that use dual-
polarization algorithms: R(KDP), R(KDP,ZDR) , R(Z,ZDR), NSSL2005.
The parameters are set in the qpe.con file located at /usr/sigmet/config/ directory.
Table 7 Algorithms for
Rain Alg
Algorithm Description
Z-R relation R(Z) This algorithm defines R-Z using the traditional
definition: Z= AR**B.
R(KDP)
R(KDP,ZDR)
R(Z,ZDR)
These algorithms compute R using the various dual-
polarization parameters.
IRIS Product and Display User Guide M211319EN-H
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