The Arden Buck equations are a group of empirical correlations that relate the
saturation vapor pressure
Vapor pressure or equilibrium vapor pressure is the pressure exerted by a vapor in thermodynamic equilibrium with its condensed phases (solid or liquid) at a given temperature in a closed system. The equilibrium vapor pressure is an indicat ...
to temperature for
moist air. The curve fits have been optimized for more accuracy than the
Goff–Gratch equation in the range .
[Buck 1981]
A set of several equations were developed, each of which is applicable in a different situation.
Formula
The equations suggested by (which are modifications of the equations in ) are:
:
, over liquid water, > 0 °C
:
, over ice, < 0 °C
where:
* is the saturation vapor pressure in
hPa
The pascal (symbol: Pa) is the unit of pressure in the International System of Units (SI). It is also used to quantify internal pressure, stress, Young's modulus, and ultimate tensile strength. The unit, named after Blaise Pascal, is an S ...
* is the
exponential function
* is the air temperature in degrees Celsius
Buck (1981) also lists enhancement factors for a temperature range of −80 to 50 °C (−112 to 122 °F) at pressures of 1,000 mb, 500 mb, and 250 mb. These coefficients are listed in the table below.
See also
*
Vapour pressure of water
The vapor pressure of water is the pressure exerted by molecules of water vapor in gaseous form (whether pure or in a mixture with other gases such as air). The saturation vapor pressure is the pressure at which water vapor is in thermodynamic eq ...
*
Antoine equation
*
Tetens equation Tetens may refer to:
People
* Alfred Tetens (1835-1903), German explorer
* Axel Tetens (1892–1961), Danish Olympic wrestler
* Johannes Nikolaus Tetens (1736–1807), German-Danish philosopher and scientist
* Otto Tetens (1865–1945), German ...
*
Lee–Kesler method
*
Goff–Gratch equation
Notes
References
*
*{{Citation
, last= Buck
, title= Buck (1996), Buck Research CR-1A User's Manual, Appendix 1..
, year= 1996
, url= http://www.hygrometers.com/wp-content/uploads/CR-1A-users-manual-2009-12.pdf
External links
Web Page listing various vapor pressure equations(for below 0 °C)
Atmospheric thermodynamics
Psychrometrics