Vertical Profile of Reflectivity (VPR)#
Precipitation is 3-dimensional in space. The vertical distribution of precipitation (and thus reflectivity) is typically non-uniform. As the height of the radar beam increases with the distance from the radar location (beam elevation, earth curvature), one sweep samples from different heights. The effects of the non-uniform VPR and the different sampling heights need to be accounted for if we are interested in the precipitation near the ground or in defined heights. This module is intended to provide a set of tools to account for these effects.
The first step will normally be to reference the polar volume data in a
3-dimensional Cartesian coordinate system. The three dimensional Cartesian
coordinates of the original polar volume data can be computed using
wradlib.vpr.volcoords_from_polar.
Then, we can create regular 3-D grids in order to analyse the vertical profile
of reflectivity or rainfall intensity. For some applications you might want
to create so-called Constant Altitude Plan Position Indicators (CAPPI)
in order to make radar observations at different distances from the radar more
comparable. Basically, a CAPPI is simply one slice out of a 3-D volume grid.
Analoguous, we will refer to the elements in a three dimensional Cartesian grid
as voxels. In wradlib, you can create
CAPPIS (CAPPI) and Pseudo CAPPIs
(PseudoCAPPI) for different altitudes at once.
Create Cartesian coordinates for regular polar volumes |
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Generate Cartesian coordinates for a regular 3-D grid based on radar specs. |
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Returns the average normalised vertical profile of a volume or any other desired statistics |
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Create 3-D regular volume grid in Cartesian coordinates from polar data with multiple elevation angles |
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Create a Constant Altitude Plan Position Indicator (CAPPI) |
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Create a Pseudo-CAPPI Constant Altitude Plan Position Indicator (CAPPI) |
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Masks the region outside the radar range |
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Masks blind regions of the radar, marked on a 3-D grid |