Source code for pycif.plugins.transforms.complex.diagmet.utils.uv_rotation
import numpy as np
[docs]
def uv_rotation(transf, inout_datastore, ddi, mapper):
"""Rotate u/v wind components from the meteorological (lat/lon) grid to the model grid.
The local grid-cell orientation :math:`(\\cos\\theta, \\sin\\theta)` is derived
from the geographic coordinates of the grid-cell corners, and winds are
rotated as :math:`u' = \\cos\\theta\\, u - \\sin\\theta\\, v`,
:math:`v' = \\sin\\theta\\, u + \\cos\\theta\\, v`. See
:doc:`/documentation/doc-models/chimere/diagmet` (section 3) for the full
derivation.
Args:
transf (Plugin): diagmet transform instance.
inout_datastore (dict): mutable datastore.
ddi (datetime): current sub-simulation date.
mapper (dict): transform mapper.
"""
# First compute sin/cos and grid centers
domain = mapper["inputs"][("meteo", "winz")]["domain"]
zlon = domain.zlon
zlat = domain.zlat
zlonc = domain.zlonc
zlatc = domain.zlatc
dx = np.degrees(np.unwrap(np.diff(np.radians(
0.5 * (zlonc[1:] + zlonc[:-1])), axis=1))) * np.cos(np.radians(zlat))
# dy = np.diff(0.5 * (zlatc[:, 1:] + zlatc[:, :-1]), axis=0)
# dx = np.degrees(np.unwrap(np.diff(np.radians(
# 0.5 * (zlonc[:, 1:] + zlonc[:, -1])), axis=0))) * np.cos(np.radians(zlat))
dy = np.diff(0.5 * (zlatc[1:] + zlatc[:-1]), axis=1)
coso = dx / np.sqrt(dx ** 2 + dy ** 2)
sino = dy / np.sqrt(dx ** 2 + dy ** 2)
# Now rotate winds
winx = inout_datastore["inputs"][("meteo", "winz")][ddi]["spec"]
winy = inout_datastore["inputs"][("meteo", "winm")][ddi]["spec"]
inout_datastore["outputs"][("meteo", "winz")][ddi]["spec"] = coso * winx - sino * winy
inout_datastore["outputs"][("meteo", "winm")][ddi]["spec"] = sino * winx + coso * winy
# WARNING!!!!!!!!!!!!!!!!!!!!!!!! TEMPORARY TO FIX ROTATION MANUALLY!!!!!!!!!
# inout_datastore["outputs"][("meteo", "winz")][ddi]["spec"] = -sino * winx - coso * winy
# inout_datastore["outputs"][("meteo", "winm")][ddi]["spec"] = coso * winx - sino * winy
