Function to calculate 100% saturated dissolved oxygen in water in mg/L as a function of temperature in degrees Celcius

Calc_DOsat100.R

# Function to calculate 100% saturated dissolved oxygen in water in mg/L as a function of temperature in degrees Celcius

Calc_DOsat100 = function(temp){
  
  # temp = temperature in degrees C
  # relationship between temperature and dissolved oxygen as defined by the APHA
  # American Public Health Association (1992)
  # Standard methods for the examination of water and wastewater. 18th ed. Washington DC.
  
  # Required constants
  
  C1 = 139.34411
  C2 = 1.575701e+5
  C3 = 6.642308e+7
  C4 = 1.243800e+10
  C5 = 8.621949e+11
  
  Ta =temp + 273.15
  
  exp(-C1 +  C2/Ta - C3/(Ta^2) + C4/(Ta^3) - C5/(Ta^4))
  
}