R/sw_adtgrad.R

In marelac: Tools for Aquatic Sciences

## -----------------------------------------------------------------------------
## Adiabatic Temperature Gradient of Seawater
## -----------------------------------------------------------------------------

sw_adtgrad <- function (S = 35, t = 25, p = P-1.013253, P = 1.013253) {
  if (any (S<0))
    stop ("Salinity should be >= 0")
  P   <- p*10 #hydrostatic pressure, in dbar
  val <-  3.5803e-5 + (8.5258e-6 + (-6.836e-8 + 6.6228e-10*t)*t)*t     +
         (1.8932e-6 - 4.2393e-8*t)*(S-35)                              +
         ((1.8741e-8 + (-6.7795e-10 + (8.733e-12 - 5.4481e-14*t)*t)*t) +
         (-1.1351e-10 + 2.7759e-12*t)*(S-35))*P                        +
         (-4.6206e-13 + (1.8676e-14 - 2.1687e-16*t)*t)*P*P
  return(val*10)        # K/dbar->K/bar
}