Note

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ICON Cell-centered wind barb plots

This example draws ICON cell-centered wind vectors as meteorological barbs with easyclimate.plot.icon.plot_cell_barbs.

As with the quiver helper, ICON cell vectors are thinned into regular longitude-latitude bins before plotting.

import xarray as xr
import numpy as np
import cartopy.crs as ccrs
import matplotlib.pyplot as plt
import easyclimate as ecl

from easyclimate.plot.icon import plot_cell_barbs

Open a sample ICON model-level file and select the horizontal wind components stored on cell centers.

data = ecl.open_tutorial_dataset("icon_native_ml_20080909T000000Z")
u = data.u
v = data.v
u

icon_native_ml_20080909T000000Z.nc ━━━━━━━ 100.0% • 1.8/1.8 • 19.6     • 0:00:00
                                                    MB        MB/s

<xarray.DataArray 'u' (ncells: 81920)> Size: 328kB
[81920 values with dtype=float32]
Coordinates:
    clon     (ncells) float64 655kB ...
    clat     (ncells) float64 655kB ...
    time     float64 8B ...
    height   float64 8B ...
Dimensions without coordinates: ncells
Attributes:
    standard_name:                eastward_wind
    long_name:                    Zonal wind
    units:                        m s-1
    param:                        2.2.0
    CDI_grid_type:                unstructured
    number_of_grid_in_reference:  1


Draw wind barbs over a regional window on plain Matplotlib axes.

fig, ax = plt.subplots()
q = plot_cell_barbs(
    data, u, v,
    ax=ax,

    lon_min=140,
    lon_max=220,
    lat_min=25,
    lat_max=70,

    nx_bins=20,
    ny_bins=15,
    thin_method="nearest_center",
)

ax.set_title("JW Wave Wind Field\n(height = 19, plot_cell_barbs)")
JW Wave Wind Field (height = 19, plot_cell_barbs)
Text(0.5, 1.0, 'JW Wave Wind Field\n(height = 19, plot_cell_barbs)')

The same barb field can be drawn on a Cartopy projection by passing a GeoAxes and the geographic input transform. sphinx_gallery_thumbnail_number = -1

fig, ax = plt.subplots(
    subplot_kw={"projection": ccrs.PlateCarree(180)}
)
q = plot_cell_barbs(
    data, u, v,
    ax=ax,

    lon_min=140,
    lon_max=220,
    lat_min=25,
    lat_max=70,

    nx_bins=20,
    ny_bins=15,
    thin_method="nearest_center",
    transform=ccrs.PlateCarree(),
)

ax.set_title("JW Wave Wind Field\n(height = 19, plot_cell_barbs)")
ax.coastlines(resolution="110m", linewidth=0.6, color="b")
ax.gridlines(draw_labels=True, alpha=0)
JW Wave Wind Field (height = 19, plot_cell_barbs)
<cartopy.mpl.gridliner.Gridliner object at 0x74c41a3c0230>

Total running time of the script: (0 minutes 2.805 seconds)