This notebook is part of the \(\omega radlib\) documentation: https://docs.wradlib.org.

Copyright (c) \(\omega radlib\) developers. Distributed under the MIT License. See LICENSE.txt for more info.

Simple fuzzy echo classification from dual-pol moments

import wradlib
from wradlib.util import get_wradlib_data_file
import os
import numpy as np
import matplotlib.pyplot as plt
import warnings
warnings.filterwarnings('ignore')
try:
    get_ipython().magic("matplotlib inline")
except:
    plt.ion()

Setting the file paths

rhofile = get_wradlib_data_file('netcdf/TAG-20120801-140046-02-R.nc')
phifile = get_wradlib_data_file('netcdf/TAG-20120801-140046-02-P.nc')
reffile = get_wradlib_data_file('netcdf/TAG-20120801-140046-02-Z.nc')
dopfile = get_wradlib_data_file('netcdf/TAG-20120801-140046-02-V.nc')
zdrfile = get_wradlib_data_file('netcdf/TAG-20120801-140046-02-D.nc')
mapfile = get_wradlib_data_file('hdf5/TAG_cmap_sweeps_0204050607.hdf5')

Read the data (radar moments and static clutter map)

# We need to organize our data as a dictionary
dat = {}
dat["rho"], attrs_rho = wradlib.io.read_edge_netcdf(rhofile)
dat["phi"], attrs_phi = wradlib.io.read_edge_netcdf(phifile)
dat["ref"], attrs_ref = wradlib.io.read_edge_netcdf(reffile)
dat["dop"], attrs_dop = wradlib.io.read_edge_netcdf(dopfile)
dat["zdr"], attrs_zdr = wradlib.io.read_edge_netcdf(zdrfile)
dat["map"]            = wradlib.io.from_hdf5(mapfile)[0][0]

Identify non-meteorological echoes using fuzzy echo classification

See Crisologo et al. (2015) and Vulpiani et al. (2012) for details.

weights = {"zdr": 0.4,
           "rho": 0.4,
           "rho2": 0.4,
           "phi": 0.1,
           "dop": 0.1,
           "map": 0.5}
cmap, nanmask = wradlib.clutter.classify_echo_fuzzy(dat,
                                                    weights=weights,
                                                    thresh=0.5)

View classfication results

fig = plt.figure(figsize=(18,16))

#   Horizontal reflectivity
ax = plt.subplot(121, aspect="equal")
ax, pm = wradlib.vis.plot_ppi(np.ma.masked_invalid(dat["ref"]), ax=ax)
ax = wradlib.vis.plot_ppi_crosshair(site=(0,0,0),
                                    ranges=[80,160,240])
plt.xlim(-240,240)
plt.ylim(-240,240)
plt.xlabel("# bins from radar")
plt.ylabel("# bins from radar")
cbar = plt.colorbar(pm, shrink=0.3)
cbar.set_label("dBZ", fontsize = "large")

#   Echo classification
ax = plt.subplot(122, aspect="equal")
ax, pm = wradlib.vis.plot_ppi(np.ma.masked_array(cmap.astype(np.uint8),
                                                 np.isnan(dat["ref"])),
                              ax=ax, cmap="bwr")
ax = wradlib.vis.plot_ppi_crosshair(site=(0,0,0),
                                    ranges=[80,160,240])
plt.xlim(-240,240)
plt.ylim(-240,240)
plt.xlabel("# bins from radar")
plt.ylabel("# bins from radar")
cbar = plt.colorbar(pm, shrink=0.3)
cbar.set_label("meterol. echo=0 - non-meteorol. echo=1",
               fontsize = "large")