W-band radar example¶
During EUREC4A and ATOMIC NOAA deployed W-band (94 GHz) radars on both the P-3 aircraft and the ship Ron Brown. The airborne radar was operated with 220 30-meter range gates with a dwell time of 0.5 seconds. The minimum detectable reflectivity of -36 dBZ at a range of 1 km although accurate estimates of Doppler properties require about -30 dBZ at 1 km.
The data are available through the EUREC4A intake catalog.
import datetime import matplotlib.pyplot as plt import colorcet as cc %matplotlib inline import eurec4a cat = eurec4a.get_intake_catalog()
We’ll select an hour’s worth of observations from a single flight day, and mask out any observations with signal-to-noise ratio less than -10 dB.
time_slice = slice(datetime.datetime(2020, 1, 19, hour=18), datetime.datetime(2020, 1, 19, hour=19)) cloud_params = cat.P3.remote_sensing['P3-0119'].to_dask().sel(time=time_slice) w_band = cat.P3.w_band_radar['P3-0119'].to_dask().sel(time=time_slice, height=slice(0,3)) w_band = w_band.where(w_band.snr > -10)
The three main quantities measured by the radar are the reflectivity, the Doppler velocity, and the spectral width.
fig = plt.figure(figsize = (12,10.2)) axes = fig.subplots(3, 1, sharex=True) w_band.corrected_reflectivity.plot(x="time", y="height", ax = axes, vmin = -45, vmax = 20, cmap = cc.m_bgy) w_band.corrected_doppler_velocity.plot(x="time", y="height", ax = axes, vmin = -3, vmax = 3, cmap = cc.m_coolwarm) w_band.spectral_width.plot(x="time", y="height", ax = axes, vmin = 0, vmax = 2, cmap = cc.m_bmy) for ax in axes[0:2]: ax.tick_params( axis='x', # changes apply to the x-axis which='both', # both major and minor ticks are affected bottom=False, # ticks along the bottom edge are off top=False, # ticks along the top edge are off labelbottom=False) # labels along the bottom edge are off ax.xaxis.set_visible(False) fig.subplots_adjust(bottom = 0)