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definition lifted_condensation_level(number t, number td, number p)

Computes the Lifted Condensation Level of a parcel ascending from a given temperature, dewpoint and pressure, where

• • t: the start temperature in K
  • td: the start dewpoint in K
  • p: the start pressure in Pa

The LCL is the level where the parcel becomes saturated and it computed with an iterative method along the dry adiabat of the ascending parcel.

The result is a definition with two members: t and p, containing the temperature and pressure of the LCL, in K and Pa units, respectively. On error or if the LCL does not exist nil is returned.

netcdf thermo_bufr(...)

Extract vertical profiles from BUFR data in a suitable format suitable for thermodynamic diagrams (defined by Thermo View). This is a Metview icon function, for detailed documentation please see Thermo Data.

netcdf thermo_grib(...)

Extract vertical profiles from GRIB data in a suitable format for thermodynamic diagrams (defined by Thermo View). This is a Metview icon function, for detailed documentation please see Thermo Data.

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definition thermo_parcel_path(vector t, vector td, vector p, definition start_condition)

definition thermo_parcel_path(thermo_netcdf profile profile, definition start_condition)

Computes the path of an ascending thermodynamic parcel with the given start condition for the given vertical profile. It returns a definition suitable for plotting containing all the details of the data to plot parcel path, buoyancy areas and related data into a thermodynamic diagram. The vertical profile is either specified as a set of vectors where:

• • t: the temperature profile (in K or °C)
  • td: the dew point temperature profile (in K or °C)
  • p: the pressure profile (in Pa or hPa)

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• • profile: the result of a vertical profile extraction from GRIB or BUFR with the thermo_grib() or thermo_bufr() functions (see Thermo Data )., respectively.

There are four different modes to specify the a parcel's start_condition  (as a definition):

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The function returns a definition with several members to describe all th the parameters related to the parcel's ascend. These The members of this definition are as follows:

• • path: the path of the parcel. It is itself a definition with two members: t and p, each containing a list of values.
  • area: the positive and negative buoyancy areas between the parcel path and the profile. It is a list of definitions describing the areas.
  • cape: the value of the CAPE (Convective Available Potential Energy)  (J/kg)
  • cin: value the CIN (Convective Inhibition) (J/kg)
  • lcl: the Lifted Condensation Level. It is a definition with two members: t and p. If no LCL exists it is set to nil.
  • lfc: the Level of Free Convention. It is a definition with two members: t and p. If no LFC exists it is set to nil.
  • el: the Equilibrium Level. It is a definition with two members: t and p. If no EL exists it is set to nil.
  • top: the Cloud Top Level. It is defined by the pressure level where the parcel. It is a definition with two members: t and p. If no TOP exists it is set to nil.

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