lcl#
- metpy.calc.lcl(pressure, temperature, dewpoint, max_iters=None, eps=None)[source]#
Calculate the lifted condensation level (LCL) from the starting point.
The starting state for the parcel is defined by temperature,
dewpoint, and pressure. If these are arrays, this function will return a LCL for every index. This function does work with surface grids as a result.- Parameters:
pressure (
pint.Quantity) – Starting atmospheric pressuretemperature (
pint.Quantity) – Starting temperaturedewpoint (
pint.Quantity) – Starting dewpoint
- Returns:
pint.Quantity– LCL pressurepint.Quantity– LCL temperature
Examples
>>> from metpy.calc import lcl >>> from metpy.units import units >>> lcl(943 * units.hPa, 33 * units.degC, 28 * units.degC) (<Quantity(877.033549, 'hectopascal')>, <Quantity(26.7591908, 'degree_Celsius')>)
See also
Notes
From [Romps2017], this directly solves for the temperature at the LCL, Eq 22a,
\[T_{LCL} = c [W_{-1}(RH_l^{1/a} c \exp{c})]^{-1} T\]and the pressure at the LCL, Eq 22b,
\[p_{LCL} = p \left( \frac{T_{LCL}}{T} \right)^{c_{pm} / R_m}\]where \(a\) (Eq 22d), \(b\) (Eq 22e), and \(c\) (Eq 22f) are derived constants, and \(W_{-1}\) is the \(k=-1\) branch of the Lambert \(W\) function.
Changed in version 1.0: Renamed
dewptparameter todewpoint
