This uses the C function named gsw_t_freezing_exact, because the
C function named gsw_t_freezing does not produce check values that
match the Matlab function called gsw_t_freezing (see references
for those test values).
gsw_t_freezing(SA, p, saturation_fraction = 1)Absolute Salinity [ g/kg ]
sea pressure [dbar], i.e. absolute pressure [dbar] minus 10.1325 dbar
fraction of air in water [unitless]
in-situ freezing temperature (ITS-90) [ degC ]
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)
p <- c( 10, 50, 125, 250, 600, 1000)
saturation_fraction <- 1
tf <- gsw_t_freezing(SA, p, saturation_fraction)
stopifnot(all.equal(tf, c(-1.902730710149803, -1.942908619287183, -2.006861069199743,
-2.090985086875259, -2.351293130342102, -2.660498762776720)))