| VaporPressureDeficit {pvldcurve} | R Documentation |
Vapor Pressure Deficit (VPD)
Description
Calculates mole fraction vapor pressure deficit (mol * mol^-1) of the air.
Usage
VaporPressureDeficit(data, humidity = "humidity",
temperature = "temperature", atmospheric.pressure = 101.325)
Arguments
data |
data frame at least with two numeric columns of equal length containg humidity (%) and temperature (degree Celsius) |
humidity |
optional name of the column in data containing the humidity values; default: "humidity" |
temperature |
optional name of the column in data containing the temperature values; default: "temperature" |
atmospheric.pressure |
optional; default = 101.325 (atmospheric pressure at sea level) |
Details
Mole fraction vapor pressure deficit is calculated as:
(1 - RH / 100) * (VPsat / AP)
whereas RH = relative humidity (%), VPsat = saturation vapor pressure (kPA), AP = atmospheric pressure (kPA), whereas:
VPsat = 0.61121 exp ((18.678 - T 234.5^-1) (T 257.14 + T))
where T = air temperature (degree Celsius)
Value
The original data frame extended by a numeric column with the vapor pressure deficit (mol * mol^-1).
Examples
# get example data
df <- weather_data
# calculate vapor pressure deficit from weather data measured at sea level
df_with_VPD <- VaporPressureDeficit(df)
# calculate vapor pressure deficit from weather data measured at 2000 m altitude
df_with_VPD <- VaporPressureDeficit(df, atmospheric.pressure = 79.495)