limnotools: Help Tools of TU Dresden's Limnology Workgroup

`O2sat` <-
function(Tc=T-273.15, T=Tc+273.15, NN=0, S=0, method=c("APHA", "Weiss", "Paul")) {
   log10 <- function(x) log(x)/log(10)
   method <- match.arg(method)
   switch(method,
     # American Public Health Association
     APHA  = exp(-139.34411+(157570.1/T)-(66423080/T^2)+(12438000000/T^3)-
             (862194900000/T^4)),   
     # Weiss, R. (1970). "The solubility of nitrogen, oxygen, and argon 
     # in water and seawater". Deep-Sea Res. 17: 721-35.
     Weiss = 1.426 * exp(-173.4292 + 249.6339 * 100 / T + 143.3483 * log(T / 100) - 
             21.8492 * T / 100 +
             S * (-0.033096 + 0.014259 * T / 100 + - 0.001700 * (T / 100)^2)),
     # Paul, L. approximation that respects heigth above see level
     Paul = (1012-0.12 * NN)/1013*(14.674-13.644*log10(1+Tc/12.8))
   )
}