xarray CfRadial2 backend#

In this example, we read CfRadial2 data files using the xarray cfradial2 backend.

import wradlib as wrl
import wradlib_data
import warnings
from IPython.display import display

import matplotlib.pyplot as plt
import numpy as np
import xradar as xd
import xarray as xr

warnings.filterwarnings("ignore")

Load CfRadial2 Volume Data#

fpath = "netcdf/cfrad.20080604_002217_000_SPOL_v36_SUR_cfradial2.nc"
f = wradlib_data.DATASETS.fetch(fpath)
vol = xr.open_datatree(f)
Downloading file 'netcdf/cfrad.20080604_002217_000_SPOL_v36_SUR_cfradial2.nc' from 'https://github.com/wradlib/wradlib-data/raw/main/data/netcdf/cfrad.20080604_002217_000_SPOL_v36_SUR_cfradial2.nc' to '/home/docs/.cache/wradlib-data'.
# fix: remove when available in xradar
for k in vol.groups[1:]:
    vol[k].ds = (
        vol[k]
        .ds.assign(sweep_fixed_angle=vol[k].ds.attrs["fixed_angle"])
        .swap_dims(time="azimuth")
        .sortby("azimuth")
    )

Inspect RadarVolume#

display(vol)
<xarray.DataTree>
Group: /
β”‚   Dimensions:              (sweep: 9)
β”‚   Coordinates:
β”‚       sweep_mode           <U20 80B ...
β”‚       longitude            float64 8B ...
β”‚       altitude             float64 8B ...
β”‚       time                 datetime64[ns] 8B ...
β”‚       latitude             float64 8B ...
β”‚   Dimensions without coordinates: sweep
β”‚   Data variables:
β”‚       volume_number        int64 8B ...
β”‚       platform_type        <U5 20B ...
β”‚       instrument_type      <U5 20B ...
β”‚       primary_axis         <U6 24B ...
β”‚       time_coverage_start  <U20 80B ...
β”‚       time_coverage_end    <U20 80B ...
β”‚       sweep_group_name     (sweep) <U7 252B ...
β”‚       sweep_fixed_angle    (sweep) float64 72B ...
β”‚   Attributes:
β”‚       version:          2.0
β”‚       title:            None
β”‚       institution:      None
β”‚       references:       None
β”‚       source:           None
β”‚       history:          None
β”‚       comment:          im/exported using wradlib
β”‚       instrument_name:  None
β”‚       fixed_angle:      0.5
β”‚       Conventions:      Cf/Radial
β”œβ”€β”€ Group: /sweep_0
β”‚       Dimensions:             (azimuth: 480, range: 996)
β”‚       Coordinates:
β”‚         * azimuth             (azimuth) float32 2kB 0.0 0.75 1.5 ... 357.8 358.5 359.2
β”‚           time                (azimuth) datetime64[ns] 4kB 2008-06-04T00:15:34 ... ...
β”‚           elevation           (azimuth) float32 2kB ...
β”‚         * range               (range) float32 4kB 150.0 300.0 ... 1.492e+05 1.494e+05
β”‚           sweep_mode          <U20 80B ...
β”‚           longitude           float64 8B ...
β”‚           latitude            float64 8B ...
β”‚           altitude            float64 8B ...
β”‚       Data variables: (12/17)
β”‚           sweep_number        int32 4B ...
β”‚           polarization_mode   |S32 32B ...
β”‚           prt_mode            |S32 32B ...
β”‚           follow_mode         |S32 32B ...
β”‚           fixed_angle         float32 4B ...
β”‚           target_scan_rate    float32 4B ...
β”‚           ...                  ...
β”‚           n_samples           (azimuth) int32 2kB ...
β”‚           r_calib_index       (azimuth) int8 480B ...
β”‚           scan_rate           (azimuth) float32 2kB ...
β”‚           DBZ                 (azimuth, range) float32 2MB ...
β”‚           VR                  (azimuth, range) float32 2MB ...
β”‚           sweep_fixed_angle   float64 8B 0.5
β”‚       Attributes:
β”‚           fixed_angle:  0.5
β”œβ”€β”€ Group: /sweep_1
β”‚       Dimensions:             (azimuth: 480, range: 996)
β”‚       Coordinates:
β”‚         * azimuth             (azimuth) float32 2kB 0.0 0.75 1.5 ... 357.8 358.5 359.2
β”‚           time                (azimuth) datetime64[ns] 4kB 2008-06-04T00:16:21 ... ...
β”‚           elevation           (azimuth) float32 2kB ...
β”‚         * range               (range) float32 4kB 150.0 300.0 ... 1.492e+05 1.494e+05
β”‚           sweep_mode          <U20 80B ...
β”‚           longitude           float64 8B ...
β”‚           latitude            float64 8B ...
β”‚           altitude            float64 8B ...
β”‚       Data variables: (12/17)
β”‚           sweep_number        int32 4B ...
β”‚           polarization_mode   |S32 32B ...
β”‚           prt_mode            |S32 32B ...
β”‚           follow_mode         |S32 32B ...
β”‚           fixed_angle         float32 4B ...
β”‚           target_scan_rate    float32 4B ...
β”‚           ...                  ...
β”‚           n_samples           (azimuth) int32 2kB ...
β”‚           r_calib_index       (azimuth) int8 480B ...
β”‚           scan_rate           (azimuth) float32 2kB ...
β”‚           DBZ                 (azimuth, range) float32 2MB ...
β”‚           VR                  (azimuth, range) float32 2MB ...
β”‚           sweep_fixed_angle   float64 8B 1.1
β”‚       Attributes:
β”‚           fixed_angle:  1.1
β”œβ”€β”€ Group: /sweep_2
β”‚       Dimensions:             (azimuth: 480, range: 996)
β”‚       Coordinates:
β”‚         * azimuth             (azimuth) float32 2kB 0.0 0.75 1.5 ... 357.8 358.5 359.2
β”‚           time                (azimuth) datetime64[ns] 4kB 2008-06-04T00:17:07 ... ...
β”‚           elevation           (azimuth) float32 2kB ...
β”‚         * range               (range) float32 4kB 150.0 300.0 ... 1.492e+05 1.494e+05
β”‚           sweep_mode          <U20 80B ...
β”‚           longitude           float64 8B ...
β”‚           latitude            float64 8B ...
β”‚           altitude            float64 8B ...
β”‚       Data variables: (12/17)
β”‚           sweep_number        int32 4B ...
β”‚           polarization_mode   |S32 32B ...
β”‚           prt_mode            |S32 32B ...
β”‚           follow_mode         |S32 32B ...
β”‚           fixed_angle         float32 4B ...
β”‚           target_scan_rate    float32 4B ...
β”‚           ...                  ...
β”‚           n_samples           (azimuth) int32 2kB ...
β”‚           r_calib_index       (azimuth) int8 480B ...
β”‚           scan_rate           (azimuth) float32 2kB ...
β”‚           DBZ                 (azimuth, range) float32 2MB ...
β”‚           VR                  (azimuth, range) float32 2MB ...
β”‚           sweep_fixed_angle   float64 8B 1.8
β”‚       Attributes:
β”‚           fixed_angle:  1.8
β”œβ”€β”€ Group: /sweep_3
β”‚       Dimensions:             (azimuth: 480, range: 996)
β”‚       Coordinates:
β”‚         * azimuth             (azimuth) float32 2kB 0.0 0.75 1.5 ... 357.8 358.5 359.2
β”‚           time                (azimuth) datetime64[ns] 4kB 2008-06-04T00:17:54 ... ...
β”‚           elevation           (azimuth) float32 2kB ...
β”‚         * range               (range) float32 4kB 150.0 300.0 ... 1.492e+05 1.494e+05
β”‚           sweep_mode          <U20 80B ...
β”‚           longitude           float64 8B ...
β”‚           latitude            float64 8B ...
β”‚           altitude            float64 8B ...
β”‚       Data variables: (12/17)
β”‚           sweep_number        int32 4B ...
β”‚           polarization_mode   |S32 32B ...
β”‚           prt_mode            |S32 32B ...
β”‚           follow_mode         |S32 32B ...
β”‚           fixed_angle         float32 4B ...
β”‚           target_scan_rate    float32 4B ...
β”‚           ...                  ...
β”‚           n_samples           (azimuth) int32 2kB ...
β”‚           r_calib_index       (azimuth) int8 480B ...
β”‚           scan_rate           (azimuth) float32 2kB ...
β”‚           DBZ                 (azimuth, range) float32 2MB ...
β”‚           VR                  (azimuth, range) float32 2MB ...
β”‚           sweep_fixed_angle   float64 8B 2.6
β”‚       Attributes:
β”‚           fixed_angle:  2.6
β”œβ”€β”€ Group: /sweep_4
β”‚       Dimensions:             (azimuth: 480, range: 996)
β”‚       Coordinates:
β”‚         * azimuth             (azimuth) float32 2kB 0.0 0.75 1.5 ... 357.8 358.5 359.2
β”‚           time                (azimuth) datetime64[ns] 4kB 2008-06-04T00:18:41 ... ...
β”‚           elevation           (azimuth) float32 2kB ...
β”‚         * range               (range) float32 4kB 150.0 300.0 ... 1.492e+05 1.494e+05
β”‚           sweep_mode          <U20 80B ...
β”‚           longitude           float64 8B ...
β”‚           latitude            float64 8B ...
β”‚           altitude            float64 8B ...
β”‚       Data variables: (12/17)
β”‚           sweep_number        int32 4B ...
β”‚           polarization_mode   |S32 32B ...
β”‚           prt_mode            |S32 32B ...
β”‚           follow_mode         |S32 32B ...
β”‚           fixed_angle         float32 4B ...
β”‚           target_scan_rate    float32 4B ...
β”‚           ...                  ...
β”‚           n_samples           (azimuth) int32 2kB ...
β”‚           r_calib_index       (azimuth) int8 480B ...
β”‚           scan_rate           (azimuth) float32 2kB ...
β”‚           DBZ                 (azimuth, range) float32 2MB ...
β”‚           VR                  (azimuth, range) float32 2MB ...
β”‚           sweep_fixed_angle   float64 8B 3.6
β”‚       Attributes:
β”‚           fixed_angle:  3.6
β”œβ”€β”€ Group: /sweep_5
β”‚       Dimensions:             (azimuth: 480, range: 996)
β”‚       Coordinates:
β”‚         * azimuth             (azimuth) float32 2kB 0.0 0.75 1.5 ... 357.8 358.5 359.2
β”‚           time                (azimuth) datetime64[ns] 4kB 2008-06-04T00:19:28 ... ...
β”‚           elevation           (azimuth) float32 2kB ...
β”‚         * range               (range) float32 4kB 150.0 300.0 ... 1.492e+05 1.494e+05
β”‚           sweep_mode          <U20 80B ...
β”‚           longitude           float64 8B ...
β”‚           latitude            float64 8B ...
β”‚           altitude            float64 8B ...
β”‚       Data variables: (12/17)
β”‚           sweep_number        int32 4B ...
β”‚           polarization_mode   |S32 32B ...
β”‚           prt_mode            |S32 32B ...
β”‚           follow_mode         |S32 32B ...
β”‚           fixed_angle         float32 4B ...
β”‚           target_scan_rate    float32 4B ...
β”‚           ...                  ...
β”‚           n_samples           (azimuth) int32 2kB ...
β”‚           r_calib_index       (azimuth) int8 480B ...
β”‚           scan_rate           (azimuth) float32 2kB ...
β”‚           DBZ                 (azimuth, range) float32 2MB ...
β”‚           VR                  (azimuth, range) float32 2MB ...
β”‚           sweep_fixed_angle   float64 8B 4.7
β”‚       Attributes:
β”‚           fixed_angle:  4.7
β”œβ”€β”€ Group: /sweep_6
β”‚       Dimensions:             (azimuth: 480, range: 996)
β”‚       Coordinates:
β”‚         * azimuth             (azimuth) float32 2kB 0.0 0.75 1.5 ... 357.8 358.5 359.2
β”‚           time                (azimuth) datetime64[ns] 4kB 2008-06-04T00:20:15 ... ...
β”‚           elevation           (azimuth) float32 2kB ...
β”‚         * range               (range) float32 4kB 150.0 300.0 ... 1.492e+05 1.494e+05
β”‚           sweep_mode          <U20 80B ...
β”‚           longitude           float64 8B ...
β”‚           latitude            float64 8B ...
β”‚           altitude            float64 8B ...
β”‚       Data variables: (12/17)
β”‚           sweep_number        int32 4B ...
β”‚           polarization_mode   |S32 32B ...
β”‚           prt_mode            |S32 32B ...
β”‚           follow_mode         |S32 32B ...
β”‚           fixed_angle         float32 4B ...
β”‚           target_scan_rate    float32 4B ...
β”‚           ...                  ...
β”‚           n_samples           (azimuth) int32 2kB ...
β”‚           r_calib_index       (azimuth) int8 480B ...
β”‚           scan_rate           (azimuth) float32 2kB ...
β”‚           DBZ                 (azimuth, range) float32 2MB ...
β”‚           VR                  (azimuth, range) float32 2MB ...
β”‚           sweep_fixed_angle   float64 8B 6.5
β”‚       Attributes:
β”‚           fixed_angle:  6.5
β”œβ”€β”€ Group: /sweep_7
β”‚       Dimensions:             (azimuth: 480, range: 996)
β”‚       Coordinates:
β”‚         * azimuth             (azimuth) float32 2kB 0.0 0.75 1.5 ... 357.8 358.5 359.2
β”‚           time                (azimuth) datetime64[ns] 4kB 2008-06-04T00:21:02 ... ...
β”‚           elevation           (azimuth) float32 2kB ...
β”‚         * range               (range) float32 4kB 150.0 300.0 ... 1.492e+05 1.494e+05
β”‚           sweep_mode          <U20 80B ...
β”‚           longitude           float64 8B ...
β”‚           latitude            float64 8B ...
β”‚           altitude            float64 8B ...
β”‚       Data variables: (12/17)
β”‚           sweep_number        int32 4B ...
β”‚           polarization_mode   |S32 32B ...
β”‚           prt_mode            |S32 32B ...
β”‚           follow_mode         |S32 32B ...
β”‚           fixed_angle         float32 4B ...
β”‚           target_scan_rate    float32 4B ...
β”‚           ...                  ...
β”‚           n_samples           (azimuth) int32 2kB ...
β”‚           r_calib_index       (azimuth) int8 480B ...
β”‚           scan_rate           (azimuth) float32 2kB ...
β”‚           DBZ                 (azimuth, range) float32 2MB ...
β”‚           VR                  (azimuth, range) float32 2MB ...
β”‚           sweep_fixed_angle   float64 8B 9.1
β”‚       Attributes:
β”‚           fixed_angle:  9.1
└── Group: /sweep_8
        Dimensions:             (azimuth: 480, range: 996)
        Coordinates:
          * azimuth             (azimuth) float32 2kB 0.0 0.75 1.5 ... 357.8 358.5 359.2
            time                (azimuth) datetime64[ns] 4kB 2008-06-04T00:21:49 ... ...
            elevation           (azimuth) float32 2kB ...
          * range               (range) float32 4kB 150.0 300.0 ... 1.492e+05 1.494e+05
            sweep_mode          <U20 80B ...
            longitude           float64 8B ...
            latitude            float64 8B ...
            altitude            float64 8B ...
        Data variables: (12/17)
            sweep_number        int32 4B ...
            polarization_mode   |S32 32B ...
            prt_mode            |S32 32B ...
            follow_mode         |S32 32B ...
            fixed_angle         float32 4B ...
            target_scan_rate    float32 4B ...
            ...                  ...
            n_samples           (azimuth) int32 2kB ...
            r_calib_index       (azimuth) int8 480B ...
            scan_rate           (azimuth) float32 2kB ...
            DBZ                 (azimuth, range) float32 2MB ...
            VR                  (azimuth, range) float32 2MB ...
            sweep_fixed_angle   float64 8B 12.8
        Attributes:
            fixed_angle:  12.8

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).

vol.root
<xarray.DataTree>
Group: /
β”‚   Dimensions:              (sweep: 9)
β”‚   Coordinates:
β”‚       sweep_mode           <U20 80B ...
β”‚       longitude            float64 8B ...
β”‚       altitude             float64 8B ...
β”‚       time                 datetime64[ns] 8B ...
β”‚       latitude             float64 8B ...
β”‚   Dimensions without coordinates: sweep
β”‚   Data variables:
β”‚       volume_number        int64 8B ...
β”‚       platform_type        <U5 20B ...
β”‚       instrument_type      <U5 20B ...
β”‚       primary_axis         <U6 24B ...
β”‚       time_coverage_start  <U20 80B ...
β”‚       time_coverage_end    <U20 80B ...
β”‚       sweep_group_name     (sweep) <U7 252B ...
β”‚       sweep_fixed_angle    (sweep) float64 72B ...
β”‚   Attributes:
β”‚       version:          2.0
β”‚       title:            None
β”‚       institution:      None
β”‚       references:       None
β”‚       source:           None
β”‚       history:          None
β”‚       comment:          im/exported using wradlib
β”‚       instrument_name:  None
β”‚       fixed_angle:      0.5
β”‚       Conventions:      Cf/Radial
β”œβ”€β”€ Group: /sweep_0
β”‚       Dimensions:             (azimuth: 480, range: 996)
β”‚       Coordinates:
β”‚         * azimuth             (azimuth) float32 2kB 0.0 0.75 1.5 ... 357.8 358.5 359.2
β”‚           time                (azimuth) datetime64[ns] 4kB 2008-06-04T00:15:34 ... ...
β”‚           elevation           (azimuth) float32 2kB ...
β”‚         * range               (range) float32 4kB 150.0 300.0 ... 1.492e+05 1.494e+05
β”‚           sweep_mode          <U20 80B ...
β”‚           longitude           float64 8B ...
β”‚           latitude            float64 8B ...
β”‚           altitude            float64 8B ...
β”‚       Data variables: (12/17)
β”‚           sweep_number        int32 4B ...
β”‚           polarization_mode   |S32 32B ...
β”‚           prt_mode            |S32 32B ...
β”‚           follow_mode         |S32 32B ...
β”‚           fixed_angle         float32 4B ...
β”‚           target_scan_rate    float32 4B ...
β”‚           ...                  ...
β”‚           n_samples           (azimuth) int32 2kB ...
β”‚           r_calib_index       (azimuth) int8 480B ...
β”‚           scan_rate           (azimuth) float32 2kB ...
β”‚           DBZ                 (azimuth, range) float32 2MB ...
β”‚           VR                  (azimuth, range) float32 2MB ...
β”‚           sweep_fixed_angle   float64 8B 0.5
β”‚       Attributes:
β”‚           fixed_angle:  0.5
β”œβ”€β”€ Group: /sweep_1
β”‚       Dimensions:             (azimuth: 480, range: 996)
β”‚       Coordinates:
β”‚         * azimuth             (azimuth) float32 2kB 0.0 0.75 1.5 ... 357.8 358.5 359.2
β”‚           time                (azimuth) datetime64[ns] 4kB 2008-06-04T00:16:21 ... ...
β”‚           elevation           (azimuth) float32 2kB ...
β”‚         * range               (range) float32 4kB 150.0 300.0 ... 1.492e+05 1.494e+05
β”‚           sweep_mode          <U20 80B ...
β”‚           longitude           float64 8B ...
β”‚           latitude            float64 8B ...
β”‚           altitude            float64 8B ...
β”‚       Data variables: (12/17)
β”‚           sweep_number        int32 4B ...
β”‚           polarization_mode   |S32 32B ...
β”‚           prt_mode            |S32 32B ...
β”‚           follow_mode         |S32 32B ...
β”‚           fixed_angle         float32 4B ...
β”‚           target_scan_rate    float32 4B ...
β”‚           ...                  ...
β”‚           n_samples           (azimuth) int32 2kB ...
β”‚           r_calib_index       (azimuth) int8 480B ...
β”‚           scan_rate           (azimuth) float32 2kB ...
β”‚           DBZ                 (azimuth, range) float32 2MB ...
β”‚           VR                  (azimuth, range) float32 2MB ...
β”‚           sweep_fixed_angle   float64 8B 1.1
β”‚       Attributes:
β”‚           fixed_angle:  1.1
β”œβ”€β”€ Group: /sweep_2
β”‚       Dimensions:             (azimuth: 480, range: 996)
β”‚       Coordinates:
β”‚         * azimuth             (azimuth) float32 2kB 0.0 0.75 1.5 ... 357.8 358.5 359.2
β”‚           time                (azimuth) datetime64[ns] 4kB 2008-06-04T00:17:07 ... ...
β”‚           elevation           (azimuth) float32 2kB ...
β”‚         * range               (range) float32 4kB 150.0 300.0 ... 1.492e+05 1.494e+05
β”‚           sweep_mode          <U20 80B ...
β”‚           longitude           float64 8B ...
β”‚           latitude            float64 8B ...
β”‚           altitude            float64 8B ...
β”‚       Data variables: (12/17)
β”‚           sweep_number        int32 4B ...
β”‚           polarization_mode   |S32 32B ...
β”‚           prt_mode            |S32 32B ...
β”‚           follow_mode         |S32 32B ...
β”‚           fixed_angle         float32 4B ...
β”‚           target_scan_rate    float32 4B ...
β”‚           ...                  ...
β”‚           n_samples           (azimuth) int32 2kB ...
β”‚           r_calib_index       (azimuth) int8 480B ...
β”‚           scan_rate           (azimuth) float32 2kB ...
β”‚           DBZ                 (azimuth, range) float32 2MB ...
β”‚           VR                  (azimuth, range) float32 2MB ...
β”‚           sweep_fixed_angle   float64 8B 1.8
β”‚       Attributes:
β”‚           fixed_angle:  1.8
β”œβ”€β”€ Group: /sweep_3
β”‚       Dimensions:             (azimuth: 480, range: 996)
β”‚       Coordinates:
β”‚         * azimuth             (azimuth) float32 2kB 0.0 0.75 1.5 ... 357.8 358.5 359.2
β”‚           time                (azimuth) datetime64[ns] 4kB 2008-06-04T00:17:54 ... ...
β”‚           elevation           (azimuth) float32 2kB ...
β”‚         * range               (range) float32 4kB 150.0 300.0 ... 1.492e+05 1.494e+05
β”‚           sweep_mode          <U20 80B ...
β”‚           longitude           float64 8B ...
β”‚           latitude            float64 8B ...
β”‚           altitude            float64 8B ...
β”‚       Data variables: (12/17)
β”‚           sweep_number        int32 4B ...
β”‚           polarization_mode   |S32 32B ...
β”‚           prt_mode            |S32 32B ...
β”‚           follow_mode         |S32 32B ...
β”‚           fixed_angle         float32 4B ...
β”‚           target_scan_rate    float32 4B ...
β”‚           ...                  ...
β”‚           n_samples           (azimuth) int32 2kB ...
β”‚           r_calib_index       (azimuth) int8 480B ...
β”‚           scan_rate           (azimuth) float32 2kB ...
β”‚           DBZ                 (azimuth, range) float32 2MB ...
β”‚           VR                  (azimuth, range) float32 2MB ...
β”‚           sweep_fixed_angle   float64 8B 2.6
β”‚       Attributes:
β”‚           fixed_angle:  2.6
β”œβ”€β”€ Group: /sweep_4
β”‚       Dimensions:             (azimuth: 480, range: 996)
β”‚       Coordinates:
β”‚         * azimuth             (azimuth) float32 2kB 0.0 0.75 1.5 ... 357.8 358.5 359.2
β”‚           time                (azimuth) datetime64[ns] 4kB 2008-06-04T00:18:41 ... ...
β”‚           elevation           (azimuth) float32 2kB ...
β”‚         * range               (range) float32 4kB 150.0 300.0 ... 1.492e+05 1.494e+05
β”‚           sweep_mode          <U20 80B ...
β”‚           longitude           float64 8B ...
β”‚           latitude            float64 8B ...
β”‚           altitude            float64 8B ...
β”‚       Data variables: (12/17)
β”‚           sweep_number        int32 4B ...
β”‚           polarization_mode   |S32 32B ...
β”‚           prt_mode            |S32 32B ...
β”‚           follow_mode         |S32 32B ...
β”‚           fixed_angle         float32 4B ...
β”‚           target_scan_rate    float32 4B ...
β”‚           ...                  ...
β”‚           n_samples           (azimuth) int32 2kB ...
β”‚           r_calib_index       (azimuth) int8 480B ...
β”‚           scan_rate           (azimuth) float32 2kB ...
β”‚           DBZ                 (azimuth, range) float32 2MB ...
β”‚           VR                  (azimuth, range) float32 2MB ...
β”‚           sweep_fixed_angle   float64 8B 3.6
β”‚       Attributes:
β”‚           fixed_angle:  3.6
β”œβ”€β”€ Group: /sweep_5
β”‚       Dimensions:             (azimuth: 480, range: 996)
β”‚       Coordinates:
β”‚         * azimuth             (azimuth) float32 2kB 0.0 0.75 1.5 ... 357.8 358.5 359.2
β”‚           time                (azimuth) datetime64[ns] 4kB 2008-06-04T00:19:28 ... ...
β”‚           elevation           (azimuth) float32 2kB ...
β”‚         * range               (range) float32 4kB 150.0 300.0 ... 1.492e+05 1.494e+05
β”‚           sweep_mode          <U20 80B ...
β”‚           longitude           float64 8B ...
β”‚           latitude            float64 8B ...
β”‚           altitude            float64 8B ...
β”‚       Data variables: (12/17)
β”‚           sweep_number        int32 4B ...
β”‚           polarization_mode   |S32 32B ...
β”‚           prt_mode            |S32 32B ...
β”‚           follow_mode         |S32 32B ...
β”‚           fixed_angle         float32 4B ...
β”‚           target_scan_rate    float32 4B ...
β”‚           ...                  ...
β”‚           n_samples           (azimuth) int32 2kB ...
β”‚           r_calib_index       (azimuth) int8 480B ...
β”‚           scan_rate           (azimuth) float32 2kB ...
β”‚           DBZ                 (azimuth, range) float32 2MB ...
β”‚           VR                  (azimuth, range) float32 2MB ...
β”‚           sweep_fixed_angle   float64 8B 4.7
β”‚       Attributes:
β”‚           fixed_angle:  4.7
β”œβ”€β”€ Group: /sweep_6
β”‚       Dimensions:             (azimuth: 480, range: 996)
β”‚       Coordinates:
β”‚         * azimuth             (azimuth) float32 2kB 0.0 0.75 1.5 ... 357.8 358.5 359.2
β”‚           time                (azimuth) datetime64[ns] 4kB 2008-06-04T00:20:15 ... ...
β”‚           elevation           (azimuth) float32 2kB ...
β”‚         * range               (range) float32 4kB 150.0 300.0 ... 1.492e+05 1.494e+05
β”‚           sweep_mode          <U20 80B ...
β”‚           longitude           float64 8B ...
β”‚           latitude            float64 8B ...
β”‚           altitude            float64 8B ...
β”‚       Data variables: (12/17)
β”‚           sweep_number        int32 4B ...
β”‚           polarization_mode   |S32 32B ...
β”‚           prt_mode            |S32 32B ...
β”‚           follow_mode         |S32 32B ...
β”‚           fixed_angle         float32 4B ...
β”‚           target_scan_rate    float32 4B ...
β”‚           ...                  ...
β”‚           n_samples           (azimuth) int32 2kB ...
β”‚           r_calib_index       (azimuth) int8 480B ...
β”‚           scan_rate           (azimuth) float32 2kB ...
β”‚           DBZ                 (azimuth, range) float32 2MB ...
β”‚           VR                  (azimuth, range) float32 2MB ...
β”‚           sweep_fixed_angle   float64 8B 6.5
β”‚       Attributes:
β”‚           fixed_angle:  6.5
β”œβ”€β”€ Group: /sweep_7
β”‚       Dimensions:             (azimuth: 480, range: 996)
β”‚       Coordinates:
β”‚         * azimuth             (azimuth) float32 2kB 0.0 0.75 1.5 ... 357.8 358.5 359.2
β”‚           time                (azimuth) datetime64[ns] 4kB 2008-06-04T00:21:02 ... ...
β”‚           elevation           (azimuth) float32 2kB ...
β”‚         * range               (range) float32 4kB 150.0 300.0 ... 1.492e+05 1.494e+05
β”‚           sweep_mode          <U20 80B ...
β”‚           longitude           float64 8B ...
β”‚           latitude            float64 8B ...
β”‚           altitude            float64 8B ...
β”‚       Data variables: (12/17)
β”‚           sweep_number        int32 4B ...
β”‚           polarization_mode   |S32 32B ...
β”‚           prt_mode            |S32 32B ...
β”‚           follow_mode         |S32 32B ...
β”‚           fixed_angle         float32 4B ...
β”‚           target_scan_rate    float32 4B ...
β”‚           ...                  ...
β”‚           n_samples           (azimuth) int32 2kB ...
β”‚           r_calib_index       (azimuth) int8 480B ...
β”‚           scan_rate           (azimuth) float32 2kB ...
β”‚           DBZ                 (azimuth, range) float32 2MB ...
β”‚           VR                  (azimuth, range) float32 2MB ...
β”‚           sweep_fixed_angle   float64 8B 9.1
β”‚       Attributes:
β”‚           fixed_angle:  9.1
└── Group: /sweep_8
        Dimensions:             (azimuth: 480, range: 996)
        Coordinates:
          * azimuth             (azimuth) float32 2kB 0.0 0.75 1.5 ... 357.8 358.5 359.2
            time                (azimuth) datetime64[ns] 4kB 2008-06-04T00:21:49 ... ...
            elevation           (azimuth) float32 2kB ...
          * range               (range) float32 4kB 150.0 300.0 ... 1.492e+05 1.494e+05
            sweep_mode          <U20 80B ...
            longitude           float64 8B ...
            latitude            float64 8B ...
            altitude            float64 8B ...
        Data variables: (12/17)
            sweep_number        int32 4B ...
            polarization_mode   |S32 32B ...
            prt_mode            |S32 32B ...
            follow_mode         |S32 32B ...
            fixed_angle         float32 4B ...
            target_scan_rate    float32 4B ...
            ...                  ...
            n_samples           (azimuth) int32 2kB ...
            r_calib_index       (azimuth) int8 480B ...
            scan_rate           (azimuth) float32 2kB ...
            DBZ                 (azimuth, range) float32 2MB ...
            VR                  (azimuth, range) float32 2MB ...
            sweep_fixed_angle   float64 8B 12.8
        Attributes:
            fixed_angle:  12.8

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-dependent metadata (like fixed_angle, sweep_mode etc.).

display(vol["sweep_0"])
<xarray.DataTree 'sweep_0'>
Group: /sweep_0
    Dimensions:             (sweep: 9, azimuth: 480, range: 996)
    Coordinates:
      * azimuth             (azimuth) float32 2kB 0.0 0.75 1.5 ... 357.8 358.5 359.2
        time                (azimuth) datetime64[ns] 4kB 2008-06-04T00:15:34 ... ...
        elevation           (azimuth) float32 2kB ...
      * range               (range) float32 4kB 150.0 300.0 ... 1.492e+05 1.494e+05
        sweep_mode          <U20 80B ...
        longitude           float64 8B ...
        latitude            float64 8B ...
        altitude            float64 8B ...
    Dimensions without coordinates: sweep
    Data variables: (12/17)
        sweep_number        int32 4B ...
        polarization_mode   |S32 32B ...
        prt_mode            |S32 32B ...
        follow_mode         |S32 32B ...
        fixed_angle         float32 4B ...
        target_scan_rate    float32 4B ...
        ...                  ...
        n_samples           (azimuth) int32 2kB ...
        r_calib_index       (azimuth) int8 480B ...
        scan_rate           (azimuth) float32 2kB ...
        DBZ                 (azimuth, range) float32 2MB ...
        VR                  (azimuth, range) float32 2MB ...
        sweep_fixed_angle   float64 8B 0.5
    Attributes:
        fixed_angle:  0.5

Georeferencing#

swp = vol["sweep_0"].ds.copy()
swp = swp.assign_coords(sweep_mode=swp.sweep_mode)
swp = swp.wrl.georef.georeference()

Inspect radar moments#

The DataArrays can be accessed by key or by attribute. Each DataArray has dimensions and coordinates of its parent dataset. There are attributes connected which are defined by Cf/Radial standard.

display(swp.DBZ)
<xarray.DataArray 'DBZ' (azimuth: 480, range: 996)> Size: 2MB
[478080 values with dtype=float32]
Coordinates: (12/15)
  * azimuth     (azimuth) float32 2kB 0.0 0.75 1.5 2.25 ... 357.8 358.5 359.2
    time        (azimuth) datetime64[ns] 4kB 2008-06-04T00:15:34 ... 2008-06-...
    elevation   (azimuth) float32 2kB 0.5164 0.5219 0.5164 ... 0.5219 0.5219
  * range       (range) float32 4kB 150.0 300.0 450.0 ... 1.492e+05 1.494e+05
    x           (azimuth, range) float64 4MB -6.556e-06 ... -1.955e+03
    y           (azimuth, range) float64 4MB 150.0 300.0 ... 1.492e+05 1.493e+05
    ...          ...
    bins        (azimuth, range) float32 2MB 150.0 300.0 ... 1.492e+05 1.494e+05
    sweep_mode  <U20 80B 'azimuth_surveillance'
    longitude   float64 8B 120.4
    latitude    float64 8B 22.53
    altitude    float64 8B 45.0
    crs_wkt     int64 8B 0
Attributes:
    long_name:             Computed Horizontal Co-polar Reflectivit
    standard_name:         equivalent_reflectivity_factor
    units:                 dBZ
    threshold_field_name:  
    threshold_value:       -9999.0
    sampling_ratio:        1.0
    grid_mapping:          grid_mapping

Create simple plot#

Using xarray features a simple plot can be created like this. Note the sortby('time') method, which sorts the radials by time.

For more details on plotting radar data see under Visualization.

swp.DBZ.sortby("time").plot(x="range", y="time", add_labels=False)
<matplotlib.collections.QuadMesh at 0x7321c3d4a120>
../../../_images/5fdbf52c21b3122416c07550c9281f628804326df940e60162e7d8107551d26d.png
fig = plt.figure(figsize=(5, 5))
pm = swp.DBZ.wrl.vis.plot(crs={"latmin": 3e3}, fig=fig)
../../../_images/5dce0ac4c95aa5f1791944df49fb4f9822fb779f57a50d46ae58f1c56b730986.png