arlmet.Grid.rotate_winds#

Grid.rotate_winds(u, v, lon, lat)[source]#

Rotate grid-relative wind components to earth-relative ones.

Winds in ARL files on projected grids are stored relative to the grid axes, which is what HYSPLIT expects. This rotates them by the meridian convergence at each point so that u points east and v north. Lat/lon grids are returned unchanged.

Parameters:

u (NDArray[Any] | float) – Grid-relative wind components.
v (NDArray[Any] | float) – Grid-relative wind components.
lon (NDArray[Any] | float) – Geographic coordinates of each wind, in degrees.
lat (NDArray[Any] | float) – Geographic coordinates of each wind, in degrees.

Returns:

Earth-relative (u, v) with the broadcast shape of the inputs.

Return type:

tuple[NDArray[Any], NDArray[Any]]