pvtend.d_dlambda

pvtend.d_dlambda(field: ndarray, dlambda: float, periodic: bool = True) → ndarray

Zonal derivative in angular coordinates ∂f/∂λ.

Matches LOG20 d_dlambda.m: centred differences in the interior, 3-point one-sided stencils at boundaries (non-periodic), or periodic wrapping.

Parameters:

• field – 2-D (nlat, nlon) or 3-D (nlev, nlat, nlon).

• dlambda – Zonal grid spacing in radians.

• periodic – Wrap zonally (default True for full-globe grids).

Returns:

Same shape, in [field_units / radian].