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ICON Cell-centered quiver plots

This example draws ICON cell-centered wind vectors with easyclimate.plot.icon.plot_cell_quiver.

The helper thins irregular ICON cell vectors into longitude-latitude bins before passing them to Matplotlib’s quiver machinery.

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_quiver

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 • 19.1     • 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 thinned vectors over a regional window on plain Matplotlib axes.

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

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

    nx_bins=30,
    ny_bins=20,
    thin_method="nearest_center",
    scale=900,
    width = 0.004,
    headaxislength = 5,
)

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

Draw the same vectors on a shifted PlateCarree map. The transform keyword identifies the input wind locations as geographic coordinates. sphinx_gallery_thumbnail_number = -1

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

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

    nx_bins=30,
    ny_bins=20,
    thin_method="nearest_center",
    scale=900,
    width = 0.004,
    headaxislength = 5,
    transform=ccrs.PlateCarree(),
)

ax.set_title("JW Wave Wind Field\n(height = 19, plot_cell_quiver)")
ax.coastlines(resolution="110m", linewidth=0.6, color="b")
ax.gridlines(draw_labels=True, alpha=0)
JW Wave Wind Field (height = 19, plot_cell_quiver)
<cartopy.mpl.gridliner.Gridliner object at 0x7a8799db7d10>

Total running time of the script: (0 minutes 2.790 seconds)