-
Notifications
You must be signed in to change notification settings - Fork 268
Commit
This commit does not belong to any branch on this repository, and may belong to a fork outside of the repository.
DOC: Add dealias example with xradar (#1472)
* ADD: Add dealias example with xradar * Fix misspelling of velocities
- Loading branch information
Showing
1 changed file
with
108 additions
and
0 deletions.
There are no files selected for viewing
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Original file line number | Diff line number | Diff line change |
---|---|---|
@@ -0,0 +1,108 @@ | ||
""" | ||
================================================= | ||
Dealias Radial Velocities Using Xradar and Py-ART | ||
================================================= | ||
An example which uses xradar and Py-ART to dealias radial velocities. | ||
""" | ||
|
||
# Author: Max Grover ([email protected]) | ||
# License: BSD 3 clause | ||
|
||
|
||
import cartopy.crs as ccrs | ||
import matplotlib.pyplot as plt | ||
import xradar as xd | ||
|
||
import pyart | ||
from pyart.testing import get_test_data | ||
|
||
# Locate the test data and read in using xradar | ||
filename = get_test_data("swx_20120520_0641.nc") | ||
tree = xd.io.open_cfradial1_datatree(filename) | ||
|
||
# Give the tree Py-ART radar methods | ||
radar = pyart.xradar.Xradar(tree) | ||
|
||
# Determine the nyquist velocity using the maximum radial velocity from the first sweep | ||
nyq = radar["sweep_0"]["mean_doppler_velocity"].max().values | ||
|
||
# Set the nyquist to what we captured above | ||
# Calculate the velocity texture | ||
vel_texture = pyart.retrieve.calculate_velocity_texture( | ||
radar, vel_field="mean_doppler_velocity", nyq=nyq | ||
) | ||
radar.add_field("velocity_texture", vel_texture, replace_existing=True) | ||
|
||
########################################## | ||
# **Visualize our velocity texture field** | ||
# Let's use the RadarMapDisplay to visualize the texture field | ||
|
||
fig = plt.figure(figsize=[8, 8]) | ||
display = pyart.graph.RadarMapDisplay(radar) | ||
display.plot_ppi_map( | ||
"velocity_texture", | ||
sweep=2, | ||
resolution="50m", | ||
vmin=0, | ||
vmax=10, | ||
projection=ccrs.PlateCarree(), | ||
cmap="pyart_balance", | ||
) | ||
plt.show() | ||
|
||
################################################## | ||
# **Determine a Velocity Texture Threshold Value** | ||
# | ||
# We can use the xradar/xarray plotting functionality here | ||
radar["sweep_0"]["velocity_texture"].plot.hist() | ||
plt.show() | ||
|
||
############################# | ||
# **Apply a Gatefilter Mask** | ||
# | ||
# We now apply this threshold, along with a reflectivity threshold, | ||
# and make use of the region-based dealiasing algorithm | ||
|
||
# Configure the gatefilter | ||
gatefilter = pyart.filters.GateFilter(radar) | ||
gatefilter.exclude_above("velocity_texture", 4) | ||
gatefilter.exclude_below("corrected_reflectivity_horizontal", 0) | ||
|
||
# At this point, we can simply used dealias_region_based to dealias the velocities | ||
# and then add the new field to the radar. | ||
velocity_dealiased = pyart.correct.dealias_region_based( | ||
radar, | ||
vel_field="mean_doppler_velocity", | ||
nyquist_vel=nyq, | ||
centered=True, | ||
gatefilter=gatefilter, | ||
) | ||
radar.add_field("corrected_velocity", velocity_dealiased, replace_existing=True) | ||
|
||
############################################# | ||
# **Visualize the Cleaned Radial Velocities** | ||
# | ||
# We can visualize the uncorrected and corrected radial velocity fields | ||
fig = plt.figure(figsize=(14, 5)) | ||
display = pyart.graph.RadarMapDisplay(radar) | ||
ax1 = plt.subplot(121) | ||
display.plot_ppi( | ||
"mean_doppler_velocity", | ||
cmap="twilight_shifted", | ||
vmin=-40, | ||
vmax=40, | ||
colorbar_label="Uncorrected Radial Velocity (m/s)", | ||
ax=ax1, | ||
) | ||
ax2 = plt.subplot(122) | ||
display.plot_ppi( | ||
"corrected_velocity", | ||
cmap="twilight_shifted", | ||
vmin=-40, | ||
vmax=40, | ||
colorbar_label="Corrected Radial Velocity (m/s)", | ||
ax=ax2, | ||
) | ||
plt.show() |