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equivalent_potential_temperature#

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

Calculate equivalent potential temperature.

This calculation must be given an air parcel’s pressure, temperature, and dewpoint. The implementation uses the formula outlined in [Bolton1980]:

First, the LCL temperature is calculated:

\[T_{L}=\frac{1}{\frac{1}{T_{D}-56}+\frac{ln(T_{K}/T_{D})}{800}}+56\]

Which is then used to calculate the potential temperature at the LCL:

\[\theta_{DL}=T_{K}\left(\frac{1000}{p-e}\right)^k \left(\frac{T_{K}}{T_{L}}\right)^{.28r}\]

Both of these are used to calculate the final equivalent potential temperature:

\[\theta_{E}=\theta_{DL}\exp\left[\left(\frac{3036.}{T_{L}} -1.78\right)*r(1+.448r)\right]\]
Parameters:
Returns:

pint.Quantity – Equivalent potential temperature of the parcel

Examples

>>> from metpy.calc import equivalent_potential_temperature
>>> from metpy.units import units
>>> equivalent_potential_temperature(850*units.hPa, 20*units.degC, 18*units.degC)
<Quantity(353.937994, 'kelvin')>

Notes

[Bolton1980] formula for Theta-e is used, since according to [DaviesJones2009] it is the most accurate non-iterative formulation available.

Examples using metpy.calc.equivalent_potential_temperature#

Equivalent Potential Temperature

Equivalent Potential Temperature
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