R/fun_schmidt_oxygen.R

In jmarriola/fwoxy: Forward model of estuary dissolved oxygen time series

#' Schmidt number calculation
#'
#' @details
#'
#' Adapted from Matlab to R by Jill Arriola, 2021-03-16
#'
#' THIS FUNCTION IS USED TO CALCULATE THE SCHMIDT NUMBER FOR THE AIR-SEA GAS
#' TRANSFER VELOCITY COMPONENT OF fwoxy.R
#'
#' @param temp numeric for temperature
#' @param salt numeric for salinity
#'
#' @return sc (unitless)
#' @export
#'
fun_schmidt_oxygen <- function(temp, salt){

  salt0 <- 0 #S=0
  param0 <- c(1745.1, -124.34, 4.8055, -0.10115, 0.00086842) # polynomial coeff at S=0
  salt35 <-  35 #S=35
  param35 <- c(1920.4, -135.6, 5.2122, -0.10939, 0.00093777) # polynomial coeff at S=35

  # calculate Sc at Salt=0"
  param <- param0
  sc0 <- (param[1]) + (param[2] * temp) + (param[3] * temp^2) + (param[4] * temp^3) + (param[5] * temp^4)

  # calculate Sc at Salt=35
  param <- param35
  sc35 <- param[1] + (param[2] * temp) + (param[3] * temp^2) + (param[4] * temp^3) + (param[5] * temp^4)

  # linearly interpolate to call Sc at given Salinity
  sc <- sc0 + (salt * ((sc35 - sc0)/(salt35 - salt0)))

return(sc)

}