Calculate water density

Calculates the density of water (kg/m^3) from temperature in degrees Celsius and salinity. For freshwater (salinity = 0) the density follows the recommended pure-water (SMOW) equation of Tanaka et al. (2001) from 0°C to 40°C, falling back to Kell (1975) above 40°C (valid to 150°C). For seawater (nonzero salinity) it follows the one-atmosphere international equation of state of Millero and Poisson (1981), valid from 0°C to 40°C and salinity 0.5 to 43. A warning is issued for temperatures or salinities outside the valid range of the equation used.

Usage

calc_water_density(water_temp, salinity = 0)

Arguments

water_temp

Numeric vector. Water temperature in degrees Celsius.

salinity

Numeric vector. Salinity in parts per thousand. Defaults to freshwater (0). Any nonzero value uses the Millero and Poisson (1981) seawater equation.

Value

Numeric vector of water density in kg/m^3.

References

Tanaka, M., Girard, G., Davis, R., Peuto, A., and Bignell, N. (2001). Recommended table for the density of water between 0°C and 40°C based on recent experimental reports. Metrologia, 38(4), 301–309. doi:10.1088/0026-1394/38/4/3

Kell, G. S. (1975). Density, thermal expansivity, and compressibility of liquid water from 0° to 150°C: Correlations and tables for atmospheric pressure and saturation reviewed and expressed on 1968 temperature scale. Journal of Chemical and Engineering Data, 20(1), 97–105. doi:10.1021/je60064a005

Millero, F. J., and Poisson, A. (1981). International one-atmosphere equation of state of seawater. Deep-Sea Research Part A, 28(6), 625–629. doi:10.1016/0198-0149(81)90122-9

Examples

calc_water_density(15)
#> [1] 999.1026
calc_water_density(c(0, 10, 20, 30))
#> [1] 999.8428 999.7027 998.2067 995.6488

# Seawater density at salinity 35
calc_water_density(15, salinity = 35)
#> [1] 1025.973