Visualizing the wind retrieval

PyDDA’s pydda.vis module provides routines for plotting horizontal and vertical cross-sections of retrieved wind fields overlaid on a gridded radar background field (e.g., reflectivity). Three wind-vector styles are supported:

• Quivers — arrow length proportional to wind speed.

• Barbs — meteorological wind barbs.

• Streamlines — continuous flow lines.

Each style has three geometry variants:

Function	Cross-section
pydda.vis.plot_horiz_xsection_quiver()	Horizontal (constant altitude)
pydda.vis.plot_xz_xsection_quiver()	Vertical, east–west (constant y)
pydda.vis.plot_yz_xsection_quiver()	Vertical, north–south (constant x)
pydda.vis.plot_horiz_xsection_barbs()	Horizontal (constant altitude)
pydda.vis.plot_xz_xsection_barbs()	Vertical, east–west (constant y)
pydda.vis.plot_yz_xsection_barbs()	Vertical, north–south (constant x)
pydda.vis.plot_horiz_xsection_streamline()	Horizontal (constant altitude)

Horizontal cross-section (quiver)

The most common visualization is a horizontal cross-section of horizontal winds overlaid on reflectivity. The example below plots the wind field at vertical level 15, with updraft contours at 1, 2, 5, and 10 m/s and quivers spaced 25 km apart.

pydda.vis.plot_horiz_xsection_quiver(
    grids_out,
    level=15,
    cmap="ChaseSpectral",
    vmin=-10,
    vmax=80,
    quiverkey_len=10.0,
    background_field="DBZ",
    bg_grid_no=1,
    w_vel_contours=[1, 2, 5, 10],
    quiver_spacing_x_km=25.0,
    quiver_spacing_y_km=25.0,
    quiverkey_loc="bottom_right",
)

(Source code, png, hires.png, pdf)

Key parameters

level

The index of the vertical level (z dimension) to plot for horizontal cross-sections.

background_field

The name of the gridded variable to show as the color-filled background (e.g., "DBZ" for reflectivity).

bg_grid_no

Which grid in the input list to use for the background field. Defaults to 0.

w_vel_contours

List of vertical velocity values (m/s) at which to draw contours. Set to None to suppress vertical velocity contours.

quiver_spacing_x_km / quiver_spacing_y_km

Horizontal spacing between quiver arrows in kilometers. Larger values produce a less cluttered plot.

quiverkey_len

The reference wind speed (m/s) represented by the quiver key arrow.

For full parameter descriptions see the Developer Reference Manual reference guide.