sigma_to_pressure#

metpy.calc.sigma_to_pressure(sigma, pressure_sfc, pressure_top)[source]#

Calculate pressure from sigma values.

Parameters:

sigma (numpy.ndarray) – Sigma levels to be converted to pressure levels
pressure_sfc (pint.Quantity) – Surface pressure value
pressure_top (pint.Quantity) – Pressure value at the top of the model domain

Returns:

pint.Quantity – Pressure values at the given sigma levels

Examples

>>> import numpy as np
>>> from metpy.calc import sigma_to_pressure
>>> from metpy.units import units
>>> sigma_levs = np.linspace(0, 1, 10)
>>> sigma_to_pressure(sigma_levs, 1000 * units.hPa, 10 * units.hPa)
<Quantity([  10.  120.  230.  340.  450.  560.  670.  780.  890. 1000.], 'hectopascal')>

Notes

Sigma definition adapted from [Philips1957]:

\[p = \sigma * (p_{sfc} - p_{top}) + p_{top}\]

\(p\) is pressure at a given sigma level
\(\sigma\) is non-dimensional, scaled pressure
\(p_{sfc}\) is pressure at the surface or model floor
\(p_{top}\) is pressure at the top of the model domain

Changed in version 1.0: Renamed psfc, ptop parameters to pressure_sfc, pressure_top