2. Configure the VVP product:
Min/Max Range
Select the minimum range to avoid strong ground clutter near the radar, for
example, 2 ... 5 km (1.2 ... 3.1 mi).
Select the maximum range so that the highest elevation angle extends past the
maximum height that you select.
No comma is required to separate the numbers.
Min/Max Height
Configure the minimum and maximum height to cover the span of altitude where
you want wind information.
Height Levels
Specify the number of height intervals. The example in the figure covers the
height span from 0.5 ... 15.0 km (0.3 ... 9.3 mi) in 20 intervals, so one value for
each 500 meters (0.3 mi).
Min Velocity
Specify the minimum velocity to be included in the wind volume fit.
The recommended value is 0.5 m/s (1 ft 8 in / s).
This is a simple way to remove bias toward 0 at low heights due to clutter which
passes the clutter filter.
A value of 0 disables Min Velocity.
Bin Quota
The maximum number of bins that is included in the least squares fit for each
height interval. The maximum allowed is 10,000 bins. Vaisala recommends using
the maximum of 10,000.
If you only select the mean velocity (that is, vertical velocity, divergence and
deformation are not selected), you can reduce the bin quota for faster product
generation.
Unfolding
Unfolding can be turned on or o.
The unfolding technique
2)
, is based on selected prototype wind profiles to
determine which yields the best result in the least squares fit.
During processing, the VVP is run several times, and the best result is selected.
In general, the VVP technique and the unfolding require at least 90° of echo
coverage for reliable results.
Reflectivity, Vertical Wind, Divergence, Deformation
VVP can optionally compute the vertical velocity, deformation, and axis of
dilatation of the wind field and the mean reflectivity profile above the radar.
Select the parameters you want to compute and record.
Note that the vertical velocity is the particle velocity. The eect of fallspeed is
included.
2) Siggia and Holmes, 1991 25th Conference on Radar Meteorology, Paris
IRIS Product and Display User Guide M211319EN-H
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