The Arden Buck equations are a group of empirical correlations that relate the saturation vapor pressure to temperature for moist air

Vapour pressure of water

The vapour pressure of water is the pressure at which steam is saturated. At higher pressures water would condense. Vapour pressure is a function of temperature...

. The curve fits have been optimized for more accuracy than the Goff–Gratch equation in the range −80 to 50°C.

A set of several equations were developed, each of which is applicable in a different situation.

Formula

The equation suggested by (which is a modification of the equation in ) is:

where:

• p_w is the saturation vapor pressure in hPa
  Pascal (unit)
  The pascal is the SI derived unit of pressure, internal pressure, stress, Young's modulus and tensile strength, named after the French mathematician, physicist, inventor, writer, and philosopher Blaise Pascal. It is a measure of force per unit area, defined as one newton per square metre...
  
  
• exp is the natural (i.e. base e) exponential function
  Exponential function
  In mathematics, the exponential function is the function ex, where e is the number such that the function ex is its own derivative. The exponential function is used to model a relationship in which a constant change in the independent variable gives the same proportional change In mathematics,...
  
  
• t is the air temperature in degrees Celsius

External links

• Web Page listing various vapor pressure equations

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