gsw_specvol_second_derivatives_wrt_enthalpy function

Second Derivatives of Specific Volume wrt Enthalpy

gsw_specvol_second_derivatives_wrt_enthalpy(SA, CT, p)

Arguments

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

Returns

A list containing specvol_SA_SA [ (m^3/kg)/(g/kg)^2 ], the second derivative of specific volume with respect to Absolute Salinity, specvol_SA_h [ (m^3/kg)/(g/kg)/(J/kg) ], the derivative of specific volume with respect to Absolute Salinity and enthalpy, and specvol_h_h [ (m^3/kg)/(J/kg)^2 ], the second derivative of specific volume with respect to enthalpy.

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)
CT <- c(28.8099, 28.4392, 22.7862, 10.2262,  6.8272,  4.3236)
p <- c(      10,      50,     125,     250,     600,    1000)

r <- gsw_specvol_second_derivatives_wrt_enthalpy(SA, CT, p)

stopifnot(all.equal(r$specvol_SA_SA/1e-8, c(0.080898741086877,
            0.080931595349498, 0.084648485333225, 0.096952812049233,
            0.099684475381589, 0.101288447077547)))
stopifnot(all.equal(r$specvol_SA_h/1e-12, c(0.325437133570796,
            0.327060462851431, 0.375273569184178, 0.545188833073084,
            0.589424881889351, 0.616101548209175)))
stopifnot(all.equal(r$specvol_h_h/1e-15, c(0.447949998681476, 0.449121446914278,
            0.485998151346315, 0.598480711660961, 0.628708349875318,
            0.647433212216398)))

References

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