Extract a radar column above a point#

Given a radar and a point, extract the column of radar data values above a point

# Author: Maxwell Grover (mgrover@anl.gov)
# License: BSD 3 clause

import cartopy.crs as ccrs
import matplotlib.pyplot as plt
import numpy as np

import pyart
from pyart.testing import get_test_data

# Read in some test data
filename = get_test_data("swx_20120520_0641.nc")
radar = pyart.io.read(filename)

Plot the first sweep and our desired point

Let’s visualize our radar data from a single sweep, and plot the location of our desired point on a map. This will provide some context as to where we are extracting our column of values.

site_lon = -97.73  # longitude in degrees
site_lat = 36.41  # latitdue in degrees

# Setup the RadarMapDisplay and add our projection
display = pyart.graph.RadarMapDisplay(radar)
ax = plt.subplot(111, projection=ccrs.PlateCarree())

# Visualize the reflectivity field, using the lowest sweep with
# latitude and longitude lines
display.plot_ppi_map(
    "reflectivity_horizontal",
    0,
    ax=ax,
    vmin=-32,
    vmax=64.0,
    lon_lines=np.arange(-98, -97, 0.2),
    lat_lines=np.arange(36, 37, 0.2),
)

# Plot our site location on top of the radar image
ax.scatter(site_lon, site_lat, color="black")

Now that we have our point defined, and our radar object, we can use the following utility function in Py-ART to subset a column

ds = pyart.util.columnsect.get_field_location(radar, site_lat, site_lon)

This function returns an xarray dataset, with all of our data fields!

print(ds)

Visualize the Reflectivity Values in the Column

Let’s visualize the reflectivity values in the column above our point, which is stored in our new dataset

ds.corrected_reflectivity_horizontal.plot(y="height")

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