earthkit.meteo.thermo.lcl_temperature

earthkit.meteo.thermo.lcl_temperature(t: ArrayLike, td: ArrayLike, method: str = 'davies') → ArrayLike
earthkit.meteo.thermo.lcl_temperature(t: xarray.DataArray, td: xarray.DataArray, method: str = 'davies') → xarray.DataArray
earthkit.meteo.thermo.lcl_temperature(t: earthkit.data.FieldList, td: earthkit.data.FieldList, method: str = 'davies') → earthkit.data.FieldList

Compute the Lifting Condensation Level (LCL) temperature from dewpoint.

Parameters:

  • t (number or array-like) – Temperature at the start level (K)

  • td (number or array-like) – Dewpoint at the start level (K)

  • method (str, optional) – The computation method: “davies” or “bolton”.

Returns:

Temperature of the LCL (K)

Return type:

number or array-like

The actual computation is based on the method:

  • “davies”: the formula by [DaviesJones1983] is used (it is also used by the IFS model):

    \[t_{LCL} = td - (0.212 + 1.571\times 10^{-3} (td - t_{0}) - 4.36\times 10^{-4} (t - t_{0})) (t - td)\]

    where \(t_{0}\) is the triple point of water (see earthkit.meteo.constants.T0).

  • “bolton”: the formula by [Bolton1980] is used:

    \[t_{LCL} = 56.0 + \frac{1}{\frac{1}{td - 56} + \frac{log(\frac{t}{td})}{800}}\]

Implementations

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

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