gsw_pot_enthalpy_ice_freezing_first_derivatives function

First Derivatives of Potential Enthalpy

gsw_pot_enthalpy_ice_freezing_first_derivatives(SA, p)

Arguments

• SA: Absolute Salinity [ g/kg ]. The valid range for most gsw functions is 0 to 42 g/kg.
• p: sea pressure [dbar], i.e. absolute pressure [dbar] minus 10.1325 dbar

Returns

A list containing pot_enthalpy_ice_freezing_SA [ (J/kg)/(g/kg) ], the derivative of potential enthalpy with respect to Absolute Salinity, and pot_enthalpy_ice_freezing_p [ unitless ], the derivative of Conservative Temperature with respect to potential temperature. (Note that the second quantity is denoted pot_enthalpy_ice_freezing_P in the documentation for the Matlab function.)

Implementation Note

This R function uses a wrapper to a C function contained within the GSW-C system as updated 2022-10-11 at https://github.com/TEOS-10/GSW-C with git commit 657216dd4f5ea079b5f0e021a4163e2d26893371.

The C function uses data from the library/gsw_data_v3_0.mat

file provided in the GSW-Matlab source code, version 3.06-11. Unfortunately, this version of the mat file is no longer displayed on the TEOS-10.org website. Therefore, in the interests of making GSW-R be self-contained, a copy was downloaded from http://www.teos-10.org/software/gsw_matlab_v3_06_11.zip on 2022-05-25, the .mat file was stored in the developer/create_data directory of https://github.com/TEOS-10/GSW-R, and then the dataset used in GSW-R was created based on that .mat file.

Please consult http://www.teos-10.org to learn more about the various TEOS-10 software systems.

Examples

SA <- c(34.7118, 34.8915, 35.0256, 34.8472, 34.7366, 34.7324)
p <- c(      10,      50,     125,     250,     600,    1000)
r <- gsw_pot_enthalpy_ice_freezing_first_derivatives(SA, p)
stopifnot(all.equal(r$pot_enthalpy_ice_freezing_SA/1e2,
      c(-1.183484968590718, -1.184125268891200, -1.184619267864844,
      -1.184026131143674, -1.183727706650925, -1.183814873741961)))
stopifnot(all.equal(r$pot_enthalpy_ice_freezing_p/1e-3,
      c(-0.202880939983260, -0.203087335312542, -0.203473018454630,
      -0.204112435106666, -0.205889571619502, -0.207895691215823)))

References

http://www.teos-10.org/pubs/gsw/html/gsw_pot_enthalpy_ice_freezing_first_derivatives.html