hesseflux.esat

esat : Saturation vapour pressure of water and ice.

This module was written by Matthias Cuntz while at Department of Computational Hydrosystems, Helmholtz Centre for Environmental Research - UFZ, Leipzig, Germany, and continued while at Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Nancy, France.

Copyright (c) 2012-2020 Matthias Cuntz - mc (at) macu (dot) de Released under the MIT License; see LICENSE file for details.

  • Written Jan 2012 by Matthias Cuntz (mc (at) macu (dot) de)
  • Ported to Python 3, Feb 2013, Matthias Cuntz
  • Changed handling of masked arrays, Oct 2013, Matthias Cuntz
  • Assert T>0, Apr 2014, Matthias Cuntz
  • Using numpy docstring format, May 2020, Matthias Cuntz

The following functions are provided

esat(T[, liquid, formula]) Calculates the saturation vapour pressure of water and/or ice.
esat(T, liquid=False, formula='GoffGratch')[source]

Calculates the saturation vapour pressure of water and/or ice.

For temperatures above (and equal) 0 degree C (273.15 K), the vapour pressure over liquid water is calculated. For temperatures below 0 degree C, the vapour pressure over ice is calculated.

The optional parameter liquid=True changes the calculation to vapour pressure over liquid water over the entire temperature range.

Parameters:
  • T (float or array_like) – Temperature [K]
  • liquid (bool, optional) – If True, use liquid formula for all temperatures.
  • formula (str, optional) –

    Name of reference to use for calculations, case-insensitive (default: GoffGratch).

    Note that several formulations do not provide a vapour pressure formulation over ice and Marti and Mauersberger do not provide a formula over liquid: GoffGratch is used in theses cases.

    GoffGratch: Smithsonian Tables, 1984; after Goff and Gratch, 1946 (default)

    MartiMauersberger: Marti and Mauersberger, 1993

    MagnusTeten: Murray, 1967

    Buck_original: Buck, 1981

    Buck: Buck Research Manual, 1996

    WMO: Goff, 1957; WMO 1988, 2000

    Wexler: Wexler, 1977

    Sonntag: Sonntag, 1994

    Bolton: Bolton, 1980

    Fukuta: Fukuta, N. and C. M. Gramada, 2003

    HylandWexler: Hyland and Wexler, 1983

    IAPWS: Wagner and Pruss, 2002

    MurphyKoop: Murphy and Koop, 2005
Returns:

Saturation water pressure at temperature T in Pascal [Pa].
Return type:

float or array_like

Notes

From Holger Voemel: http://cires.colorado.edu/~voemel/vp.html

Referred literature cited in code.

Examples

>>> print('{:.3f}'.format(esat(293.15)))
2335.847
>>> print('{:.3f}'.format(esat(253.15)))
103.074

>>> print('{:.3f} {:.3f}'.format(*esat([293.15,253.15])))
2335.847 103.074
>>> print('{:.3f} {:.3f}'.format(*esat([293.15,253.15],formula='GoffGratch')))
2335.847 103.074
>>> print('{:.3f} {:.3f}'.format(*esat([293.15,253.15],formula='MartiMauersberger')))
2335.847 103.650
>>> print('{:.3f} {:.3f}'.format(*esat([293.15,253.15],formula='MagnusTeten')))
2335.201 102.771
>>> print('{:.3f} {:.3f}'.format(*esat([293.15,253.15],formula='buck')))
2338.340 103.286
>>> print('{:.3f} {:.3f}'.format(*esat([293.15,253.15],formula='Buck_original')))
2337.282 103.267
>>> print('{:.3f} {:.3f}'.format(*esat([293.15,253.15],formula='wmo')))
2337.080 103.153
>>> print('{:.3f} {:.3f}'.format(*esat([293.15,253.15],formula='WEXLER')))
2323.254 103.074
>>> print('{:.3f} {:.3f}'.format(*esat([293.15,253.15],formula='Sonntag')))
2339.249 103.249
>>> print('{:.3f} {:.3f}'.format(*esat([293.15,253.15],formula='Bolton')))
2336.947 103.074
>>> print('{:.3f} {:.3f}'.format(*esat([293.15,253.15],formula='Fukuta')))
2335.847 103.074
>>> print('{:.3f} {:.3f}'.format(*esat([293.15,253.15],formula='HylandWexler')))
2338.804 103.260
>>> print('{:.3f} {:.3f}'.format(*esat([293.15,253.15],formula='IAPWS')))
2339.194 103.074
>>> print('{:.3f} {:.3f}'.format(*esat([293.15,253.15],formula='MurphyKoop')))
2339.399 103.252

>>> print('{:.3f} {:.3f}'.format(*esat(np.array([293.15,253.15]), liquid=True)))
2335.847 125.292
>>> print('{:.3f} {:.3f}'.format(*esat([293.15,253.15],formula='Fukuta', liquid=True)))
2335.847 125.079

>>> print('{:.3f} {:.3f}'.format(*esat(np.array([293.15,393.15]))))
esat.py: UserWarning: T>373.15 K - something might be wrong with T.
2335.847 198473.378
>>> print('{:.3f} {:.3f}'.format(*esat(np.array([293.15,93.15]))))
esat.py: UserWarning: T<100 - T probably given in Celsius instead of Kelvin.
2335.847 0.000

>>> out = esat(np.ma.array([253.15,-9999.], mask=[False,True]))
>>> print('{:.3f} {:.3f}'.format(*out.filled(-9999.)))
103.074 -9999.000