Source code for pycif.plugins.datastreams.fields.noaa_glob_avg.get_domain

import datetime
import glob
import os

import numpy as np
import xarray as xr

from .....utils.classes.setup import Setup
from .....utils.classes.domains import Domain
from .....utils.check.errclass import CifError
from .....utils.hdf5 import _hdf5_lock




def get_domain(ref_dir, ref_file, input_interval, target_dir, tracer=None):
    """Build a global cyclic Domain from a NOAA reference file.

    Looks for a reference NetCDF file in ``ref_dir``, either an exact
    match for ``ref_file`` or the first file whose name matches
    ``ref_file`` used as a date-format pattern, then builds a global
    cyclic lon-lat grid from its ``longitude``/``latitude`` variables and
    vertical mid-levels from its ``pressure`` variable (with ``sigma_b``
    set to zero, i.e. a purely pressure-based vertical coordinate).

    Args:
        ref_dir: directory to search for a reference file.
        ref_file: exact file name, or a date-format pattern used to
            match one of the files in ``ref_dir``.
        input_interval: unused, accepted for interface compatibility.
        target_dir: unused, accepted for interface compatibility.
        tracer: unused, accepted for interface compatibility.

    Returns:
        Domain: the NOAA grid domain.

    Raises:
        CifError: if no reference file can be found in ``ref_dir``.
    """

    # Looking for a reference file to read lon/lat in
    list_file = glob.glob(f"{ref_dir}/*nc")

    # Either a file is specified in the Yaml
    domain_file = None
    if ref_file in list_file:
        domain_file = f"{ref_dir}/{ref_file}"

    # Or loop over available file regarding file pattern
    else:
        for flx_file in list_file:
            try:
                date = datetime.datetime.strptime(
                    os.path.basename(flx_file), ref_file
                )
                domain_file = flx_file
                break
            except ValueError:
                continue

    if domain_file is None:
        raise CifError(
            "EDGARv5 domain could not be initialized as no file was found"
        )

    # Read lon/lat in
    with _hdf5_lock:
        nc = xr.open_dataset(domain_file, decode_times=False)
        lonc = np.concatenate([nc["longitude"].values, [180]])
        latc = np.concatenate([nc["latitude"].values, [90]])
        zlonc, zlatc = np.meshgrid(lonc, latc)

        lon = 0.5 * (lonc[1:] + lonc[:-1])
        lat = 0.5 * (latc[1:] + latc[:-1])
        zlon, zlat = np.meshgrid(lon, lat)

        nlon = lon.size
        nlat = lat.size

        # Initializes vertical resolution
        pres = nc["pressure"]
        nlev = len(pres)
        sigma_a_mid = pres.values
        sigma_b_mid = 0. * pres.values

    # Initializes domain
    domain = Domain(
        nlon=nlon, nlat=nlat, zlon=zlon, zlat=zlat,
        zlonc=zlonc, zlatc=zlatc,
        pressure_unit="Pa", lon_cyclic=True, nlev=nlev,
        sigma_a_mid=sigma_a_mid, sigma_b_mid=sigma_b_mid,
    )

    return domain