xarray CfRadial1 backend#

In this example, we read CfRadial1 data files using the xradar cfradial1 backend.

Data is also exported to ODIM_H5 and CfRadial2.

[1]:
import wradlib as wrl
import warnings

warnings.filterwarnings("ignore")
import matplotlib.pyplot as pl
import numpy as np
import xradar as xd
import datatree as xt
import xarray as xr

try:
    get_ipython().run_line_magic("matplotlib inline")
except:
    pl.ion()

Load CfRadial1 Volume Data#

We use the functionality provided now by xradar to read the CfRadial1 data into a DataTree.

[2]:
fpath = "netcdf/cfrad.20080604_002217_000_SPOL_v36_SUR.nc"
f = wrl.util.get_wradlib_data_file(fpath)
vol = xd.io.open_cfradial1_datatree(f)
Downloading file 'netcdf/cfrad.20080604_002217_000_SPOL_v36_SUR.nc' from 'https://github.com/wradlib/wradlib-data/raw/pooch/data/netcdf/cfrad.20080604_002217_000_SPOL_v36_SUR.nc' to '/home/runner/work/wradlib/wradlib/wradlib-data'.

Inspect RadarVolume#

[3]:
display(vol)
<xarray.DatasetView>
Dimensions:              (sweep: 9)
Dimensions without coordinates: sweep
Data variables:
    volume_number        int32 ...
    platform_type        |S32 ...
    primary_axis         |S32 ...
    status_str           |S1 ...
    instrument_type      |S32 ...
    time_coverage_start  |S32 ...
    time_coverage_end    |S32 ...
    latitude             float64 ...
    longitude            float64 ...
    altitude             float64 ...
    sweep_group_name     (sweep) <U7 'sweep_0' 'sweep_1' ... 'sweep_7' 'sweep_8'
    sweep_fixed_angle    (sweep) float32 ...
Attributes: (12/13)
    Conventions:         CF/Radial instrument_parameters radar_parameters rad...
    version:             1.2
    title:               TIMREX
    institution:
    references:
    source:
    ...                  ...
    comment:
    instrument_name:     SPOLRVP8
    site_name:
    scan_name:
    scan_id:             0
    platform_is_mobile:  false

Inspect root group#

The sweep dimension contains the number of scans in this radar volume. Further the dataset consists of variables (location coordinates, time_coverage) and attributes (Conventions, metadata).

[4]:
vol.root
[4]:
<xarray.DatasetView>
Dimensions:              (sweep: 9)
Dimensions without coordinates: sweep
Data variables:
    volume_number        int32 ...
    platform_type        |S32 ...
    primary_axis         |S32 ...
    status_str           |S1 ...
    instrument_type      |S32 ...
    time_coverage_start  |S32 ...
    time_coverage_end    |S32 ...
    latitude             float64 ...
    longitude            float64 ...
    altitude             float64 ...
    sweep_group_name     (sweep) <U7 'sweep_0' 'sweep_1' ... 'sweep_7' 'sweep_8'
    sweep_fixed_angle    (sweep) float32 ...
Attributes: (12/13)
    Conventions:         CF/Radial instrument_parameters radar_parameters rad...
    version:             1.2
    title:               TIMREX
    institution:
    references:
    source:
    ...                  ...
    comment:
    instrument_name:     SPOLRVP8
    site_name:
    scan_name:
    scan_id:             0
    platform_is_mobile:  false

Inspect sweep group(s)#

The sweep-groups can be accessed via their respective keys. The dimensions consist of range and time with added coordinates azimuth, elevation, range and time. There will be variables like radar moments (DBZH etc.) and sweep-dependend metadata (like fixed_angle, sweep_mode etc.).

[5]:
display(vol["sweep_0"])
<xarray.DatasetView>
Dimensions:                    (azimuth: 483, range: 996)
Coordinates:
    time                       (azimuth) datetime64[ns] 2008-06-04T00:15:34 ....
  * range                      (range) float32 150.0 300.0 ... 1.494e+05
  * azimuth                    (azimuth) float32 0.0 0.75 1.5 ... 358.5 359.2
    elevation                  (azimuth) float32 ...
    latitude                   float64 ...
    longitude                  float64 ...
    altitude                   float64 ...
Data variables: (12/18)
    sweep_number               int32 ...
    sweep_mode                 |S32 ...
    prt_mode                   |S32 ...
    follow_mode                |S32 ...
    sweep_fixed_angle          float32 ...
    pulse_width                (azimuth) timedelta64[ns] ...
    ...                         ...
    r_calib_index              (azimuth) int8 ...
    measured_transmit_power_h  (azimuth) float32 ...
    measured_transmit_power_v  (azimuth) float32 ...
    scan_rate                  (azimuth) float32 ...
    DBZ                        (azimuth, range) float32 ...
    VR                         (azimuth, range) float32 ...