Source code for pycif.plugins.datastreams.meteos.chimere_meteo.read

import os
import datetime
import numpy as np
import xarray as xr

from .....utils.netcdf import readnc
from .....utils.check.errclass import CifValueError




def read(
        self,
        name,
        varnames,
        dates,
        files,
        interpol_flx=False,
        comp_type=None,
        ddi=None,
        **kwargs
):
    """Read requested variables from CHIMERE METEO.nc files.

    For each ``[period, file]`` pair, reads ``varnames`` (falling back to
    ``name`` if ``varnames`` is empty) and the ``Times`` variable from the
    file, parses ``Times`` to locate the array index matching the
    requested period start (optionally offset from ``ddi`` instead of the
    file's own first time stamp), and extracts that hourly slice.

    Args:
        self: the meteo Plugin (uses ``self.model.periods`` when raising
            the interpolation-misconfiguration error).
        name: name of the component/variable to read, used as a fallback
            when ``varnames`` is empty.
        varnames: name of the NetCDF variable to extract; must not be an
            empty string.
        dates: list of ``[start, end]`` date pairs, aligned with ``files``.
        files: list of CHIMERE METEO.nc files to read from, aligned with
            ``dates``.
        interpol_flx (bool): unused here (kept for interface consistency).
        comp_type: unused here (kept for interface consistency).
        ddi: optional reference date used instead of the file's first
            ``Times`` entry to compute the hourly index to extract.

    Returns:
        xarray.DataArray: extracted data stacked over ``dates``, with dims
        ``(time, lev, lat, lon)``.

    Raises:
        CifValueError: if ``varnames`` is an empty string, which happens
            when the meteo needs interpolating to another domain or
            temporal resolution but the input datavect does not list all
            required variables explicitly.
    """

    # Raise Exception if varname is empty string
    if varnames == '':
        raise CifValueError(
            "Varname is empty string. Can't read raw meteo files.\n"
            "This happens when trying to spatially or temporally interpolate input files "
            "to another domain or temporal resolution.\n"
            "If one want to interpolate a METEO file to another domain, "
            "ALL meteo variables should be included explicitly in the datavect of the YAML file.\n"
            "Please also check that the temporal split (e.g., METEO files per 24h period) "
            "is the same in the input and in the model resolution.\n"
            f"In the present case, the expected sub-period length is: {self.model.periods} "
            f"whereas file Time length is {len(readnc(files[0], ['Times'])) - 1}h"
        )

    var2extract = varnames if varnames != "" else name

    # Reading required meteo files
    trcr_met = []
    for period, ff in zip(dates, files):
        data, times = readnc(ff, [var2extract, "Times"])

        # Force conversion to float64
        data = data.astype(float)

        # Get the correct hour in the file
        times = [
            datetime.datetime.strptime(
                str(b"".join(s), "utf-8"), "%Y-%m-%d_%H:%M:%S"
            )
            for s in times
        ]
        hour = int((period[0] - times[0]).total_seconds() // 3600)
        if ddi is not None:
            hour = int((period[0] - ddi).total_seconds() // 3600)

        trcr_met.append(data[hour, ...])

    # Building a xarray
    xmod = xr.DataArray(
        trcr_met, coords={"time": np.array(dates)[:, 0]},
        dims=("time", "lev", "lat", "lon")
    )

    return xmod