earthkit.meteo.thermo.fieldlist.lcl_temperature

earthkit.meteo.thermo.fieldlist.lcl_temperature(t, td, method='davies')

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

Parameters:

  • t (FieldList|Field) – Temperature at the start level (K).

  • td (FieldList|Field) – Dewpoint at the start level (K).

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

Returns:

Temperature of the LCL (K). The result has the same type as the input t and td (FieldList or Field).

Return type:

FieldList|Field

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:

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