parcel_profile#
- metpy.calc.parcel_profile(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.- Parameters:
pressure (
pint.Quantity
) – Atmospheric pressure level(s) of interest. This array must be from high to low pressure.temperature (
pint.Quantity
) – Starting temperaturedewpoint (
pint.Quantity
) – Starting dewpoint
- Returns:
pint.Quantity
– The parcel’s temperatures at the specified pressure levels
Examples
>>> from metpy.calc import dewpoint_from_relative_humidity, parcel_profile >>> 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) >>> # computer parcel temperature >>> parcel_profile(p, T[0], Td[0]).to('degC') <Quantity([ 29.3 28.61221952 25.17408111 23.41044641 21.53049669 19.51679547 17.34763012 14.99552875 12.4250297 9.58933992 6.4250951 2.84385238 -1.28217807 -6.14487817 -12.0437512 -19.45887455 -29.14459155 -42.13147376 -50.19971377 -59.49169312 -70.19973455 -82.69068969 -94.44583924 -101.13413664 -108.54542355 -116.90037584 -126.55118719 -138.11894611 -144.97290122 -152.88981956], 'degree_Celsius')>
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 todewpoint