earthkit.meteo.thermo.mixing_ratio_from_dewpoint

earthkit.meteo.thermo.mixing_ratio_from_dewpoint(td: ArrayLike, p: ArrayLike) → ArrayLike

earthkit.meteo.thermo.mixing_ratio_from_dewpoint(td: xarray.DataArray, p: xarray.DataArray) → xarray.DataArray

earthkit.meteo.thermo.mixing_ratio_from_dewpoint(td: earthkit.data.FieldList, p: earthkit.data.FieldList) → earthkit.data.FieldList

Compute the mixing ratio from dewpoint.

Parameters:

• td (array-like) – Dewpoint (K)

• p (array-like) – Pressure (Pa)

Returns:

Specific humidity (kg/kg)

Return type:

array-like

The computation starts with determining the vapour pressure:

\[e(w, p) = e_{wsat}(td)\]

where:

• \(e\) is the vapour pressure (see vapour_pressure_from_mixing_ratio())

• \(e_{wsat}\) is the saturation_vapour_pressure() over water

• \(w\) is the mixing ratio

Then w is computed from \(e\) using mixing_ratio_from_vapour_pressure().

Implementations

mixing_ratio_from_dewpoint() calls one of the following implementations depending on the type of the input arguments:

• earthkit.meteo.thermo.array.mixing_ratio_from_dewpoint() for array-like

• earthkit.meteo.thermo.xarray.mixing_ratio_from_dewpoint() for xarray.DataArray

• earthkit.meteo.thermo.fieldlist.mixing_ratio_from_dewpoint() for FieldList

The function returns an object of the same type as the input arguments.