ghcn_cams.py

"""ESMValTool CMORizer for GHCN-CAMS data.

Tier
    Tier 2: other freely-available dataset.

Source
    https://www.esrl.noaa.gov/psd/data/gridded/data.ghcncams.html
    ftp://ftp.cdc.noaa.gov/Datasets/ghcncams/air.mon.mean.nc

Last access
    20200304
"""

import logging
import os

import iris
from iris import NameConstraint

from esmvaltool.cmorizers.data import utilities as utils

logger = logging.getLogger(__name__)


def _extract_variable(short_name, var, cfg, filepath, out_dir):
    """Extract variable."""
    raw_var = var.get('raw', short_name)
    cube = iris.load_cube(filepath, NameConstraint(var_name=raw_var))

    # Fix units
    if 'raw_units' in var:
        cube.units = var['raw_units']
    cmor_info = cfg['cmor_table'].get_variable(var['mip'], short_name)
    cube.convert_units(cmor_info.units)
    utils.convert_timeunits(cube, 1950)

    # Fix coordinates
    cube = utils.fix_coords(cube)
    if 'height2m' in cmor_info.dimensions:
        utils.add_height2m(cube)

    # Fix metadata
    attrs = cfg['attributes']
    attrs['mip'] = var['mip']
    utils.fix_var_metadata(cube, cmor_info)
    utils.set_global_atts(cube, attrs)

    # Save variable
    utils.save_variable(cube,
                        short_name,
                        out_dir,
                        attrs,
                        unlimited_dimensions=['time'])


def cmorization(in_dir, out_dir, cfg, cfg_user, start_date, end_date):
    """Cmorization func call."""
    filepath = os.path.join(in_dir, cfg['filename'])

    # Run the cmorization
    for (short_name, var) in cfg['variables'].items():
        logger.info("CMORizing variable '%s'", short_name)
        _extract_variable(short_name, var, cfg, filepath, out_dir)