Calculation of the state of an air parcel subject to an adiabatic downwards evolution, taking into account the initial conditions of the parcel (Pstart, Tstart, wstart, wcstart).
Initial mixing ratio value for the condensates (kg/kg)
Pend
Final pressure value (Pa)
deltaP
Pressure step used for the calculation. It must be a positive value (Pa)
Value
This function returns a list including the following values:
Tend
Temperature at the end (K)
Wend
Mixing ratio of water vapour at the end (kg/kg)
Wcend
Mixing ratio of condensed water at the end (kg/kg)
Details
In this case, we start from a parcel at pressure pstart (Pa), temperature tstart (K) and mixing ratio wstart (kg/kg), with potentially some condensates wcstart (kg/kg). The latent heat (L) used during the evolution depends on the Temperature (T). It is computed as described by latent_heat_H2O. As the parcel goes down it could evaporate the condensates or, if no condensates are available anymore, it will go down according to a dry adiabatic evolution by means of a dry adiabatic process until the level Pend. At this point, it will have a temperature Tend, mixing ratio (vapour) Wend and Wcend (may be still some condensates could be left) using steps of pressure dP (always positive).