This uses the 75-term density equation, and returns potential density referenced to a pressure of 2000 dbar, minus 1000 kg/m^3.
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.
See also
Other things related to density:
gsw_CT_from_rho(),
gsw_CT_maxdensity(),
gsw_SA_from_rho(),
gsw_alpha(),
gsw_alpha_on_beta(),
gsw_alpha_wrt_t_exact(),
gsw_alpha_wrt_t_ice(),
gsw_beta(),
gsw_beta_const_t_exact(),
gsw_infunnel(),
gsw_pot_rho_t_exact(),
gsw_rho(),
gsw_rho_alpha_beta(),
gsw_rho_first_derivatives(),
gsw_rho_first_derivatives_wrt_enthalpy(),
gsw_rho_ice(),
gsw_rho_t_exact(),
gsw_sigma0(),
gsw_sigma1(),
gsw_sigma3(),
gsw_sigma4(),
gsw_specvol(),
gsw_specvol_alpha_beta(),
gsw_specvol_anom_standard(),
gsw_specvol_ice(),
gsw_specvol_t_exact()
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)
sigma2 <- gsw_sigma2(SA,CT)
stopifnot(all.equal(sigma2, c(30.023152223799116, 30.283783336283477, 32.265556840289719,
35.474550881051073, 36.067289438047737, 36.492606494879510)))