psychrometric.constant {bigleaf}

Psychrometric Constant

Description

Calculates the psychrometric 'constant'.

Usage

psychrometric.constant(Tair, pressure, constants = bigleaf.constants())

Arguments

Tair

Air temperature (deg C)

pressure

Atmospheric pressure (kPa)

constants

cp - specific heat of air for constant pressure (J K-1 kg-1)
eps - ratio of the molecular weight of water vapor to dry air (-)

Details

The psychrometric constant (\gamma) is given as:

\gamma = cp * pressure / (eps * \lambda)

where \lambda is the latent heat of vaporization (J kg-1), as calculated from latent.heat.vaporization.

Value

\gamma - the psychrometric constant (kPa K-1)

References

Monteith J.L., Unsworth M.H., 2008: Principles of Environmental Physics. 3rd Edition. Academic Press, London.

Examples

psychrometric.constant(seq(5,45,5),100)