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
dewpt
parameter todewpoint