Py-ART

import os
import pyart
import radarx as rx  # noqa
import cmweather  # noqa
import cartopy.crs as ccrs
from datetime import datetime

## You are using the Python ARM Radar Toolkit (Py-ART), an open source
## library for working with weather radar data. Py-ART is partly
## supported by the U.S. Department of Energy as part of the Atmospheric
## Radiation Measurement (ARM) Climate Research Facility, an Office of
## Science user facility.
##
## If you use this software to prepare a publication, please cite:
##
##     JJ Helmus and SM Collis, JORS 2016, doi: 10.5334/jors.119

Grid Setup

x_lims = (-300e3, 250e3)
y_lims = (-250e3, 300e3)
z_lims = (0, 15e3)
h_res = 2000
v_res = 500

Load data

file = "s3://noaa-nexrad-level2/2018/06/12/KSGF/KSGF20180612_083109_V06"
radar = pyart.io.read_nexrad_archive(file)
filename = os.path.basename(file) + ".nc"
if not os.path.exists(filename):
    pyart.io.write_cfradial(filename, radar)
else:
    print("Already present")

tstart = datetime.now()
# Grid using 11 vertical levels, and 101 horizontal grid cells at a resolution on 1 km
grid = pyart.map.grid_from_radars(
    (radar,),
    grid_shape=(31, 276, 276),
    grid_limits=(
        z_lims,
        y_lims,
        x_lims,
    ),
    fields=["reflectivity"],
)

xg = grid.to_xarray()
print("Py-ART gridding took:", datetime.now() - tstart)
display(xg)
del radar

Py-ART gridding took: 0:00:11.455926

<xarray.Dataset> Size: 20MB
Dimensions:                     (time: 1, z: 31, y: 276, x: 276, nradar: 1)
Coordinates: (12/16)
  * time                        (time) object 8B 2018-06-12 08:31:09.972000
  * z                           (z) float64 248B 0.0 500.0 ... 1.45e+04 1.5e+04
    lat                         (y, x) float64 609kB 34.94 34.94 ... 39.9 39.9
    lon                         (y, x) float64 609kB -96.69 -96.67 ... -90.47
  * y                           (y) float64 2kB -2.5e+05 -2.48e+05 ... 3e+05
  * x                           (x) float64 2kB -3e+05 -2.98e+05 ... 2.5e+05
    ...                          ...
    origin_altitude             (time) float64 8B 419.0
    radar_altitude              (nradar) float64 8B 419.0
    radar_latitude              (nradar) float64 8B 37.24
    radar_longitude             (nradar) float64 8B -93.4
    radar_time                  (nradar) float64 8B 0.972
    radar_name                  (nradar) <U4 16B 'KSGF'
Dimensions without coordinates: nradar
Data variables:
    reflectivity                (time, z, y, x) float32 9MB nan nan ... nan nan
    ROI                         (time, z, y, x) float32 9MB 6.816e+03 ... 6.8...
Attributes: (12/13)
    radar_name:          KSGF
    nradar:              1
    Conventions:         CF/Radial instrument_parameters
    version:             1.3
    title:
    institution:
    ...                  ...
    source:
    history:
    comment:
    instrument_name:     KSGF
    original_container:  NEXRAD Level II
    vcp_pattern:         212

xarray.Dataset

• Dimensions:
  • time: 1
  • z: 31
  • y: 276
  • x: 276
  • nradar: 1
• Coordinates: (16)
  • time
    (time)
    object
    2018-06-12 08:31:09.972000

    array([cftime.DatetimeGregorian(2018, 6, 12, 8, 31, 9, 972000, has_year_zero=False)],
          dtype=object)

  • z
    (z)
    float64
    0.0 500.0 ... 1.45e+04 1.5e+04

    array([    0.,   500.,  1000.,  1500.,  2000.,  2500.,  3000.,  3500.,  4000.,
            4500.,  5000.,  5500.,  6000.,  6500.,  7000.,  7500.,  8000.,  8500.,
            9000.,  9500., 10000., 10500., 11000., 11500., 12000., 12500., 13000.,
           13500., 14000., 14500., 15000.])

  • lat
    (y, x)
    float64
    34.94 34.94 34.94 ... 39.9 39.9

    long_name :

    latitude of grid cell center

    units :

    degree_N

    standard_name :

    Latitude

    array([[34.94085857, 34.94147055, 34.94207845, ..., 34.9559475 ,
            34.9554418 , 34.95493201],
           [34.95882825, 34.95944046, 34.96004857, ..., 34.97392267,
            34.97341678, 34.97290681],
           [34.97679792, 34.97741035, 34.97801869, ..., 34.99189783,
            34.99139176, 34.9908816 ],
           ...,
           [39.84615661, 39.84683496, 39.84750877, ..., 39.86288211,
            39.86232155, 39.86175645],
           [39.86412302, 39.86480162, 39.8654757 , ..., 39.88085507,
            39.88029429, 39.87972897],
           [39.88208941, 39.88276828, 39.88344262, ..., 39.89882802,
            39.89826702, 39.89770148]], shape=(276, 276))

  • lon
    (y, x)
    float64
    -96.69 -96.67 ... -90.49 -90.47

    long_name :

    longitude of grid cell center

    units :

    degree_E

    standard_name :

    Longitude

    array([[-96.69140131, -96.66947802, -96.6475544 , ..., -90.70147989,
            -90.67954868, -90.65761775],
           [-96.69213704, -96.67020886, -96.64828035, ..., -90.70087622,
            -90.67894012, -90.65700429],
           [-96.6928733 , -96.67094024, -96.64900684, ..., -90.70027211,
            -90.67833111, -90.65639039],
           ...,
           [-96.9141008 , -96.89069885, -96.86729644, ..., -90.51874413,
            -90.4953314 , -90.47191904],
           [-96.91500468, -96.89159673, -96.86818833, ..., -90.51800241,
            -90.49458367, -90.4711653 ],
           [-96.91590927, -96.89249531, -96.8690809 , ..., -90.51726011,
            -90.49383535, -90.47041096]], shape=(276, 276))

  • y
    (y)
    float64
    -2.5e+05 -2.48e+05 ... 3e+05

    array([-250000., -248000., -246000., ...,  296000.,  298000.,  300000.],
          shape=(276,))

  • x
    (x)
    float64
    -3e+05 -2.98e+05 ... 2.5e+05

    array([-300000., -298000., -296000., ...,  246000.,  248000.,  250000.],
          shape=(276,))

  • ProjectionCoordinateSystem
    ()
    int32
    1

    latitude_of_projection_origin :

    37.23523712158203

    longitude_of_projection_origin :

    -93.40042114257812

    _CoordinateTransformType :

    Projection

    _CoordinateAxes :

    x y z time

    _CoordinateAxesTypes :

    GeoX GeoY Height Time

    grid_mapping_name :

    azimuthal_equidistant

    semi_major_axis :

    6370997.0

    inverse_flattening :

    298.25

    longitude_of_prime_meridian :

    0.0

    false_easting :

    0.0

    false_northing :

    0.0

    array(1, dtype=int32)

  • projection
    ()
    int32
    1

    proj :

    pyart_aeqd

    _include_lon_0_lat_0 :

    true

    array(1, dtype=int32)

  • origin_latitude
    (time)
    float64
    37.24

    long_name :

    Latitude at grid origin

    units :

    degrees_north

    standard_name :

    latitude

    valid_min :

    -90.0

    valid_max :

    90.0

    array([37.23523712])

  • origin_longitude
    (time)
    float64
    -93.4

    long_name :

    Longitude at grid origin

    units :

    degrees_east

    standard_name :

    longitude

    valid_min :

    -180.0

    valid_max :

    180.0

    array([-93.40042114])

  • origin_altitude
    (time)
    float64
    419.0

    long_name :

    Altitude at grid origin

    units :

    m

    standard_name :

    altitude

    array([419.])

  • radar_altitude
    (nradar)
    float64
    419.0

    long_name :

    Altitude of radars used to make the grid.

    units :

    m

    array([419.])

  • radar_latitude
    (nradar)
    float64
    37.24

    long_name :

    Latitude of radars used to make the grid.

    units :

    degrees_north

    array([37.23523712])

  • radar_longitude
    (nradar)
    float64
    -93.4

    long_name :

    Longitude of radars used to make the grid.

    units :

    degrees_east

    array([-93.40042114])

  • radar_time
    (nradar)
    float64
    0.972

    long_name :

    Time in seconds of the volume start for each radar

    array([0.972])

  • radar_name
    (nradar)
    <U4
    'KSGF'

    long_name :

    Name of radar used to make the grid

    array(['KSGF'], dtype='<U4')

• Data variables: (2)
  • reflectivity
    (time, z, y, x)
    float32
    nan nan nan nan ... nan nan nan nan

    units :

    dBZ

    standard_name :

    equivalent_reflectivity_factor

    long_name :

    Reflectivity

    valid_max :

    94.5

    valid_min :

    -32.0

    coordinates :

    elevation azimuth range

    _FillValue :

    -9999.0

    array([[[[nan, nan, nan, ..., nan, nan, nan],
             [nan, nan, nan, ..., nan, nan, nan],
             [nan, nan, nan, ..., nan, nan, nan],
             ...,
             [nan, nan, nan, ..., nan, nan, nan],
             [nan, nan, nan, ..., nan, nan, nan],
             [nan, nan, nan, ..., nan, nan, nan]],
    
            [[nan, nan, nan, ..., nan, nan, nan],
             [nan, nan, nan, ..., nan, nan, nan],
             [nan, nan, nan, ..., nan, nan, nan],
             ...,
             [nan, nan, nan, ..., nan, nan, nan],
             [nan, nan, nan, ..., nan, nan, nan],
             [nan, nan, nan, ..., nan, nan, nan]],
    
            [[nan, nan, nan, ..., nan, nan, nan],
             [nan, nan, nan, ..., nan, nan, nan],
             [nan, nan, nan, ..., nan, nan, nan],
             ...,
    ...
             [nan, nan, nan, ..., nan, nan, nan],
             [nan, nan, nan, ..., nan, nan, nan],
             [nan, nan, nan, ..., nan, nan, nan]],
    
            [[nan, nan, nan, ..., nan, nan, nan],
             [nan, nan, nan, ..., nan, nan, nan],
             [nan, nan, nan, ..., nan, nan, nan],
             ...,
             [nan, nan, nan, ..., nan, nan, nan],
             [nan, nan, nan, ..., nan, nan, nan],
             [nan, nan, nan, ..., nan, nan, nan]],
    
            [[nan, nan, nan, ..., nan, nan, nan],
             [nan, nan, nan, ..., nan, nan, nan],
             [nan, nan, nan, ..., nan, nan, nan],
             ...,
             [nan, nan, nan, ..., nan, nan, nan],
             [nan, nan, nan, ..., nan, nan, nan],
             [nan, nan, nan, ..., nan, nan, nan]]]],
          shape=(1, 31, 276, 276), dtype=float32)

  • ROI
    (time, z, y, x)
    float32
    6.816e+03 6.79e+03 ... 6.821e+03

    standard_name :

    radius_of_influence

    long_name :

    Radius of influence for mapping

    units :

    m

    least_significant_digit :

    1

    _FillValue :

    -9999.0

    array([[[[6816.421 , 6789.639 , 6762.931 , ..., 6122.1265, 6146.662 ,
              6171.298 ],
             [6794.125 , 6767.255 , 6740.458 , ..., 6097.292 , 6121.9272,
              6146.662 ],
             [6771.9355, 6744.977 , 6718.092 , ..., 6072.5566, 6097.292 ,
              6122.1265],
             ...,
             [7356.3525, 7331.543 , 7306.8164, ..., 6718.092 , 6740.458 ,
              6762.931 ],
             [7380.913 , 7356.187 , 7331.543 , ..., 6744.977 , 6767.255 ,
              6789.639 ],
             [7405.557 , 7380.913 , 7356.3525, ..., 6771.9355, 6794.125 ,
              6816.421 ]],
    
            [[6816.4263, 6789.6445, 6762.9365, ..., 6122.1323, 6146.6685,
              6171.3037],
             [6794.131 , 6767.2607, 6740.4644, ..., 6097.2983, 6121.9336,
              6146.6685],
             [6771.9414, 6744.983 , 6718.097 , ..., 6072.563 , 6097.2983,
              6122.1323],
    ...
             [7360.7046, 7335.91  , 7311.198 , ..., 6722.8574, 6745.2085,
              6767.6655],
             [7385.2515, 7360.5396, 7335.91  , ..., 6749.724 , 6771.9863,
              6794.355 ],
             [7409.881 , 7385.2515, 7360.7046, ..., 6776.6636, 6798.838 ,
              6821.118 ]],
    
            [[6821.4478, 6794.6855, 6767.9976, ..., 6127.7227, 6152.236 ,
              6176.849 ],
             [6799.168 , 6772.318 , 6745.5415, ..., 6102.911 , 6127.524 ,
              6152.236 ],
             [6776.995 , 6750.0566, 6723.1914, ..., 6078.1987, 6102.911 ,
              6127.7227],
             ...,
             [7361.0103, 7336.217 , 7311.506 , ..., 6723.1914, 6745.5415,
              6767.9976],
             [7385.5557, 7360.8447, 7336.217 , ..., 6750.0566, 6772.318 ,
              6794.6855],
             [7410.184 , 7385.5557, 7361.0103, ..., 6776.995 , 6799.168 ,
              6821.4478]]]], shape=(1, 31, 276, 276), dtype=float32)

• Indexes: (4)
  • time
    PandasIndex

    PandasIndex(CFTimeIndex([2018-06-12 08:31:09.972000],
                dtype='object', length=1, calendar='standard', freq=None))

  • z
    PandasIndex

    PandasIndex(Index([    0.0,   500.0,  1000.0,  1500.0,  2000.0,  2500.0,  3000.0,  3500.0,
            4000.0,  4500.0,  5000.0,  5500.0,  6000.0,  6500.0,  7000.0,  7500.0,
            8000.0,  8500.0,  9000.0,  9500.0, 10000.0, 10500.0, 11000.0, 11500.0,
           12000.0, 12500.0, 13000.0, 13500.0, 14000.0, 14500.0, 15000.0],
          dtype='float64', name='z'))

  • y
    PandasIndex

    PandasIndex(Index([-250000.0, -248000.0, -246000.0, -244000.0, -242000.0, -240000.0,
           -238000.0, -236000.0, -234000.0, -232000.0,
           ...
            282000.0,  284000.0,  286000.0,  288000.0,  290000.0,  292000.0,
            294000.0,  296000.0,  298000.0,  300000.0],
          dtype='float64', name='y', length=276))

  • x
    PandasIndex

    PandasIndex(Index([-300000.0, -298000.0, -296000.0, -294000.0, -292000.0, -290000.0,
           -288000.0, -286000.0, -284000.0, -282000.0,
           ...
            232000.0,  234000.0,  236000.0,  238000.0,  240000.0,  242000.0,
            244000.0,  246000.0,  248000.0,  250000.0],
          dtype='float64', name='x', length=276))

• Attributes: (13)

  radar_name :

  KSGF

  nradar :

  1

  Conventions :

  CF/Radial instrument_parameters

  version :

  1.3

  title :

  institution :

  references :

  source :

  history :

  comment :

  instrument_name :

  KSGF

  original_container :

  NEXRAD Level II

  vcp_pattern :

  212

Plot

Py-ART

xg.squeeze().radarx.plot_max_cappi(
    data_var="reflectivity",
    vmin=-10,
    vmax=70,
    range_rings=True,
    add_map=True,
    projection=ccrs.PlateCarree(),
)