R/fun_gas_transfer_velocity.R

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

#' Gas transfer velocity calculation
#'
#' @details
#'
#' Adapted from Matlab to R by Jill Arriola, 2021-03-16
#'
#' THIS FUNCTION CALCULATES THE GAS TRANSFER VELOCITY ACROSS THE AIR-SEA
#' INTERFACE FOR OXYGEN BASED ON THE WANNINKHOF (2014) EQUATION
#'
#' Reference:
#' WANNINKHOF, R., LIMNOLOGY AND OCEANOGRAPHY METHODS, 12(6), 351-362, 2014.
#'
#' INPUTS ARE
#' sc = Schmidt number (unitless)
#' wspd2 = Windspeed squared (m^2/s^2)
#' **Inputs come from fwoxy.R as vectors**
#'
#' OUTPUT IS kw (m/s)
#'
#' @param sc numeric for Schmidt number
#' @param wspd2 numeric for windspeed
#' @param agas_param numeric for the a coefficient
#' @param gas_inv numeric for the inverse exponent function
#'
#' @return kw (m/s)
#' @export
#'
fun_gas_transfer_velocity <- function(sc, wspd2, agas_param = 0.251, gas_inv = -0.5){

  kw <- agas_param * wspd2 * ((sc / 660) ^(gas_inv)) # cm/hr
  kw  <- kw/(100*60*60) # convert from cm/hr to m/s

  return(kw)

}