pvtend.sh_ops.parity_mirror

pvtend.sh_ops.parity_mirror(field: ndarray, lat: ndarray, kind: str) → Tuple[ndarray, ndarray][source]

Mirror an NH-only field onto the full globe with the correct parity.

Constructs the full-globe field by reflecting the NH portion across the equator. Parity rules (per Phase 2 plan):

  • "scalar" / "u": field is even across the equator, F(-φ, λ) =  F(φ, λ).

  • "v" / "odd": field is odd, F(-φ, λ) = -F(φ, λ); the equator row is set to zero.

Parameters:

  • field – Array with latitude on axis -2 and longitude on axis -1. Latitudes must run from the equator (≈0) to the north pole (90).

  • lat – Latitudes in degrees, ascending, lat[0] ≈ 0, lat[-1] ≈ 90.

  • kind – Parity tag; one of "scalar", "u", "v", "odd".

Returns:

Tuple (field_global, lat_global) where field_global has latitude axis length 2 * nlat_nh - 1 and lat_global runs from −lat[-1] to +lat[-1].