Second Derivatives of Potential Temperature
gsw_pt_second_derivatives(SA, CT)Absolute Salinity [ g/kg ]
Conservative Temperature [ degC ]
A list containing pt_SA_SA [ K/(g/kg)^2 ], the second derivative of
potential temperature with respect to Absolute Salinity at constant
potential temperature, and pt_SA_pt [ 1/(g/kg) ], the derivative of
potential temperature with respect to Conservative Temperature and
Absolute Salinity, and pt_pt_pt [ 1/degC ], the second derivative of
potential temperature with respect to Conservative Temperature.
This R function uses a wrapper to a C function contained within the GSW-C system as updated 2021-12-28 at https://github.com/TEOS-10/GSW-C with git commit `98f0fd40dd9ceb0ba82c9d47ac750e935a7d0459`.
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.
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)
r <- gsw_pt_second_derivatives(SA, CT)
stopifnot(all.equal(r$pt_SA_SA/1e-3,
c(0.160307058371208, 0.160785497957769, 0.168647220588324,
0.198377949876584, 0.210181899321236, 0.220018966513329)))
stopifnot(all.equal(r$pt_SA_CT,
c(0.001185581323691, 0.001187068518686, 0.001217629686266,
0.001333254154015, 0.001379674342678, 0.001418371539325)))
stopifnot(all.equal(r$pt_CT_CT/1e-3,
c(-0.121979811279463, -0.123711264754503, -0.140136818504977,
-0.140645384127949, -0.113781055410824, -0.082417269009484)))