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parcel_profile_with_lcl#

metpy.calc.parcel_profile_with_lcl(pressure, temperature, dewpoint)[source]#

Calculate the profile a parcel takes through the atmosphere.

The parcel starts at temperature, and dewpoint, lifted up dry adiabatically to the LCL, and then moist adiabatically from there. pressure specifies the pressure levels for the profile. This function returns a profile that includes the LCL.

Parameters:

  • pressure (pint.Quantity) – Atmospheric pressure level(s) of interest. This array must be from high to low pressure.

  • temperature (pint.Quantity) – Atmospheric temperature at the levels in pressure. The first entry should be at the same level as the first pressure data point.

  • dewpoint (pint.Quantity) – Atmospheric dewpoint at the levels in pressure. The first entry should be at the same level as the first pressure data point.

Returns:

  • pressure (pint.Quantity) – The parcel profile pressures, which includes the specified levels and the LCL

  • ambient_temperature (pint.Quantity) – Atmospheric temperature values, including the value interpolated to the LCL level

  • ambient_dew_point (pint.Quantity) – Atmospheric dewpoint values, including the value interpolated to the LCL level

  • profile_temperature (pint.Quantity) – The parcel profile temperatures at all of the levels in the returned pressures array, including the LCL

Examples

>>> from metpy.calc import dewpoint_from_relative_humidity, parcel_profile_with_lcl
>>> from metpy.units import units
>>> # pressure
>>> p = [1008., 1000., 950., 900., 850., 800., 750., 700., 650., 600.,
...      550., 500., 450., 400., 350., 300., 250., 200.,
...      175., 150., 125., 100., 80., 70., 60., 50.,
...      40., 30., 25., 20.] * units.hPa
>>> # temperature
>>> T = [29.3, 28.1, 23.5, 20.9, 18.4, 15.9, 13.1, 10.1, 6.7, 3.1,
...      -0.5, -4.5, -9.0, -14.8, -21.5, -29.7, -40.0, -52.4,
...      -59.2, -66.5, -74.1, -78.5, -76.0, -71.6, -66.7, -61.3,
...      -56.3, -51.7, -50.7, -47.5] * units.degC
>>> # relative humidity
>>> rh = [.85, .65, .36, .39, .82, .72, .75, .86, .65, .22, .52,
...       .66, .64, .20, .05, .75, .76, .45, .25, .48, .76, .88,
...       .56, .88, .39, .67, .15, .04, .94, .35] * units.dimensionless
>>> # calculate dewpoint
>>> Td = dewpoint_from_relative_humidity(T, rh)
>>> # compute parcel temperature
>>> Td = dewpoint_from_relative_humidity(T, rh)
>>> p_wLCL, T_wLCL, Td_wLCL, prof_wLCL = parcel_profile_with_lcl(p, T, Td)

See also

lcl, moist_lapse, dry_lapse, parcel_profile, parcel_profile_with_lcl_as_dataset

Notes

Only functions on 1D profiles (not higher-dimension vertical cross sections or grids). Duplicate pressure levels return duplicate parcel temperatures. Consider preprocessing low-precision, high frequency profiles with tools like scipy.medfilt, pandas.drop_duplicates, or numpy.unique.

Will only return Pint Quantities, even when given xarray DataArray profiles. To obtain a xarray Dataset instead, use parcel_profile_with_lcl_as_dataset instead.

Changed in version 1.0: Renamed dewpt parameter to dewpoint

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