gsw_CT_first_derivatives function

First Derivatives of Conservative Temperature

gsw_CT_first_derivatives(SA, pt)

Arguments

• SA: Absolute Salinity [ g/kg ]. The valid range for most gsw functions is 0 to 42 g/kg.
• pt: potential temperature (ITS-90) [ degC ]

Returns

A list containing CT_SA [ K/(g/kg) ], the derivative of Conservative Temperature with respect to Absolute Salinity, and CT_pt [ unitless ], the derivative of Conservative Temperature with respect to potential temperature.

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)
pt <- c(28.7832, 28.4209, 22.7850, 10.2305,  6.8292,  4.3245)
r <- gsw_CT_first_derivatives(SA, pt)
stopifnot(all.equal(r$CT_SA,
    c(-0.041981092877806, -0.041558140199508, -0.034739209004865,
      -0.018711103772892, -0.014075941811725, -0.010571716552295)))
stopifnot(all.equal(r$CT_pt,
    c(1.002814937296636, 1.002554817053239, 1.001645140295163,
      1.000003771100520, 0.999716359504731, 0.999474326580093)))

References

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