calcRH_DP: Calculate Relative Humidity from temperature and dew point

In ConSciR: Tools for Conservation Science

Calculate Relative Humidity from temperature and dew point

Description

Function to calculate relative humidity (%) from temperature (°C) and dew point (°C)

Usage

calcRH_DP(Temp, DewP, method = c("Magnus", "Buck"))

Arguments

Temp	Temperature (°Celsius)
DewP	Td (DP), Dew Point (°Celsius)
method	Calculation method: either "Magnus" or "Buck". Defaults to "Magnus".

Details

This function supports two methods for relative humidity calculation:

• "Magnus" (default): Uses the August-Roche-Magnus approximation, valid for 0°C < Temp < 60°C and 1% < RH < 100%.

• "Buck": Uses the Arden Buck equation with Bögel modification, valid for -30°C < Temp < 60°C and 1% < RH < 100%.

The methods calculate temperature based on vapor pressure and saturation vapour pressure relationships. The Magnus method is chosen as the default because it is more stable when used with the calcDP and calcTemp functions.

Value

Relative Humidity (0-100%)

References

Alduchov, O. A., and R. E. Eskridge, 1996: Improved Magnus' form approximation of saturation vapor pressure. J. Appl. Meteor., 35, 601–609

Buck, A. L., 1981: New Equations for Computing Vapor Pressure and Enhancement Factor. J. Appl. Meteor. Climatol., 20, 1527–1532, https://doi.org/10.1175/1520-0450(1981)020<1527:NEFCVP>2.0.CO;2.

Buck (1996), Buck (1996), Buck Research CR-1A User's Manual, Appendix 1.

https://bmcnoldy.earth.miami.edu/Humidity.html

See Also

calcTemp for calculating temperature

calcDP for calculating dew point

calcRH_AH for calculating relative humidity from absolute humidity

calcRH_DP for calculating relative humidity from dew point

Examples

# Relative humidity (RH) at tempertaure of 20°C (Temp) and dew point of 15°C (DewP)
calcRH_DP(20, 15)
calcRH_DP(20, 15, method = "Buck")

calcRH_DP(20, calcDP(20, 50))

calcRH_DP(20, calcDP(20, 50, method = "Buck"), method = "Buck")

# mydata file
filepath <- data_file_path("mydata.xlsx")
mydata <- readxl::read_excel(filepath, sheet = "mydata", n_max = 5)

mydata |>
  dplyr::mutate(
    DewPoint = calcDP(Temp, RH),
    RH_default = calcRH_DP(Temp, DewPoint),
    RH_Buck = calcRH_DP(Temp, DewPoint, method = "Buck"))

ConSciR documentation built on Nov. 5, 2025, 5:25 p.m.