The Arden Buck equations are a group of empirical correlations that relate the saturation vapor pressure 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 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.
Enhancement factor (EF) °C 1,000 mb 500 mb 250 mb -80 1.004101.00200 -70 1.003601.00180 -601.006401.003201.00160 -501.005801.002901.00140 -401.005201.002601.00130 -301.004701.002401.00120 -201.004401.002201.00120 -101.004101.002201.00120 01.003951.002191.00132 101.003881.00229 201.004001.00251 301.004261.00284 401.004671.00323 501.00519
See also Vapour pressure of water Antoine equation Tetens equation Lee–Kesler method Goff–Gratch equation
Notes
References
External links Web Page listing various vapor pressure equations (for below 0 °C)