wetbulb.temp {bigleaf} | R Documentation |
calculates the wet bulb temperature, i.e. the temperature that the air would have if it was saturated.
wetbulb.temp(
Tair,
pressure,
VPD,
accuracy = 0.001,
Esat.formula = c("Sonntag_1990", "Alduchov_1996", "Allen_1998"),
constants = bigleaf.constants()
)
Tair |
Air temperature (deg C) |
pressure |
Atmospheric pressure (kPa) |
VPD |
Vapor pressure deficit (kPa) |
accuracy |
Accuracy of the result (deg C) |
Esat.formula |
Optional: formula to be used for the calculation of esat and the slope of esat.
One of |
constants |
cp - specific heat of air for constant pressure (J K-1 kg-1) |
Wet-bulb temperature (Tw) is calculated from the following expression:
e = Esat(Tw) - Le067 * gamma * (Tair - Tw)
The equation is solved for Tw using optimize
.
Actual vapor pressure e (kPa) is calculated from VPD using the function VPD.to.e
.
The psychrometric constant gamma (kPa K-1) is calculated from psychrometric.constant
.
Le067 is the Lewis number for water vapor to the power of 0.67 and represents the ratio of
aerodynamic resistance to water vapor and heat. Le067 * gamma is sometimes referred to as the
'modified psychrometric constant (gamma*).
Tw - |
wet-bulb temperature (degC) |
Monteith J.L., Unsworth M.H., 2013: Principles of Environmental Physics. Plants, Animals, and the Atmosphere. 4th edition. Academic Press.
wetbulb.temp(Tair=c(20,25),pressure=100,VPD=c(1,1.6))