Calculate Humidity Ratio

Function to calculate humidity ratio (g/kg) from temperature (°C) and relative humidity (%).

Humidity ratio is the mass of water vapor present in a given volume of air relative to the mass of dry air. Also known as "moisture content".

Function uses calcMR

Usage

calcHR(Temp, RH, P_atm = 1013.25, B = 621.9907, ...)

Arguments

Temp

Temperature (°Celsius)

RH

Relative Humidity (0-100%)

P_atm

Atmospheric pressure = 1013.25 (hPa)

B

B = 621.9907 g/kg for air

...

Additional arguments to supply to calcPws and calcMR

Value

HR Humidity ratio (g/kg)

Note

This function requires the calcMR function to be available in the environment.

See also

calcMR for calculating mixing ratio

calcAD for calculating air density

calcPw for calculating water vapour pressure

calcPws for calculating water vapour saturation pressure

Examples

# Humidity ratio at 20°C (Temp) and 50% relative humidity (RH)
calcHR(20, 50)
#> [1] 7.260814


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

mydata |> dplyr::mutate(HumidityRatio = calcHR(Temp, RH))
#> # A tibble: 5 × 6
#>   Site   Sensor Date                 Temp    RH HumidityRatio
#>   <chr>  <chr>  <dttm>              <dbl> <dbl>         <dbl>
#> 1 London Room 1 2024-01-01 00:00:00  21.8  36.8          5.96
#> 2 London Room 1 2024-01-01 00:15:00  21.8  36.7          5.94
#> 3 London Room 1 2024-01-01 00:29:59  21.8  36.6          5.92
#> 4 London Room 1 2024-01-01 00:44:59  21.7  36.6          5.89
#> 5 London Room 1 2024-01-01 00:59:59  21.7  36.5          5.87