Module gdess.operations.convert

Functions

def co2_kgfrac_to_ppm(xr_ds_: xarray.core.dataset.Dataset, co2_var_name: str = 'co2') -> xarray.core.dataset.Dataset

Convert $CO_2$ from units of kg/kg to ppm

Parameters

xr_ds_ : xarray.Dataset

A dataset containing a CO2 variable

co2_var_name : str, default 'co2'

Variable name for CO2 in the dataset

Notes

The $CO_2$ variable of the input dataset is converted from units of kg/kg to ppm by:

$$CO_2\,dry-air\,mass\,fraction \times CO_2\,molar\,mass \times dry-air\,molar\,mass \times ppm$$ $$\frac{kg_{CO_2}}{kg_{air}} \times \frac{1\,kmol_{CO_2}}{44.01\,kg_{CO_2}} \times \frac{28.9647\,kg_{air}}{1\,kmol_{air}} \times \frac{1e6\,parts_{air}}{1\,part_{CO_2}}$$ Returns

---

xarray.Dataset The dataset with CO2 converted to units of ppm

Expand source code

def co2_kgfrac_to_ppm(xr_ds_: xr.Dataset,
                      co2_var_name: str = 'co2',
                      ) -> xr.Dataset:
    """Convert \\(CO_2\\) from units of kg/kg to ppm

    Parameters
    ----------
    xr_ds_ : ``xarray.Dataset``
        A dataset containing a CO2 variable
    co2_var_name : `str`, default 'co2'
        Variable name for CO2 in the dataset

    Notes
    -----
    The \\(CO_2\\) variable of the input dataset is converted from units of kg/kg to ppm by:

    .. math::
        CO_2\\,dry-air\\,mass\\,fraction \\times CO_2\\,molar\\,mass \\times dry-air\\,molar\\,mass \\times ppm

    .. math::
        \\frac{kg_{CO_2}}{kg_{air}} \\times \\frac{1\\,kmol_{CO_2}}{44.01\\,kg_{CO_2}} \\times
            \\frac{28.9647\\,kg_{air}}{1\\,kmol_{air}} \\times \\frac{1e6\\,parts_{air}}{1\\,part_{CO_2}}

    Returns
    -------
    ``xarray.Dataset``
        The dataset with CO2 converted to units of ppm
    """
    mwco2 = 44.01
    mwdry = 28.9647
    mwfac = mwdry / mwco2
    ppmfac = mwfac * 1e6

    temp_long_name = ''
    if 'long_name' in xr_ds_[co2_var_name].attrs:
        temp_long_name = xr_ds_[co2_var_name].long_name

    # do the conversion
    xr_ds_[co2_var_name] = xr_ds_[co2_var_name]*ppmfac

    xr_ds_[co2_var_name].attrs["units"] = 'ppm'
    xr_ds_[co2_var_name].attrs['long_name'] = temp_long_name

    return xr_ds_

def co2_molfrac_to_ppm(xr_ds_: xarray.core.dataset.Dataset, co2_var_name: str = 'co2') -> xarray.core.dataset.Dataset

Convert $CO_2$ from units of mol/mol to ppm

Parameters

xr_ds_ : xarray.Dataset

A dataset containing a CO2 variable

co2_var_name : str, default 'co2'

Variable name for CO2 in the dataset

Notes

The $CO_2$ variable of the input dataset is converted from units of mol/mol to ppm by:

$$ppmfac = \times \frac{1e6\,mol_{air}}{1\,mol_{CO_2}}$$

$$CO_2\,dry\,air\,mole\,fraction\,(i.e. \frac{mol_{CO_2}}{mol_{air}}) \times ppmfac = ppm$$

Returns

xarray.DataSet The dataset with $CO_2$ converted to units of ppm

Expand source code

def co2_molfrac_to_ppm(xr_ds_: xr.Dataset,
                       co2_var_name: str = 'co2',
                       ) -> xr.Dataset:
    """Convert \\(CO_2\\) from units of mol/mol to ppm

    Parameters
    ----------
    xr_ds_ : ``xarray.Dataset``
        A dataset containing a CO2 variable
    co2_var_name : `str`, default 'co2'
        Variable name for CO2 in the dataset

    Notes
    -----
    The \\(CO_2\\) variable of the input dataset is converted from units of mol/mol to ppm by:

    $$ppmfac = \\times \\frac{1e6\\,mol_{air}}{1\\,mol_{CO_2}}$$

    $$CO_2\\,dry\\,air\\,mole\\,fraction\\,(i.e. \\frac{mol_{CO_2}}{mol_{air}}) \\times ppmfac = ppm$$

    Returns
    -------
    ``xarray.DataSet``
        The dataset with \\(CO_2\\) converted to units of ppm
    """
    ppmfac = 1e6

    temp_long_name = xr_ds_[co2_var_name].long_name
    _logger.debug("\toriginal units <%s>", xr_ds_[co2_var_name].attrs['units'])

    # do the conversion
    xr_ds_[co2_var_name] = xr_ds_[co2_var_name]*ppmfac

    xr_ds_[co2_var_name].attrs["units"] = 'ppm'
    xr_ds_[co2_var_name].attrs['long_name'] = temp_long_name

    _logger.debug("\tnew units <%s>", xr_ds_[co2_var_name].attrs['units'])

    return xr_ds_