In-situ density, thermal expansion coefficient and haline contraction coefficient (75-term equation)

Calculate the in-situ density, the expansion coefficient (with respect to Conservative Temperature) and the haline contraction coefficient (with respect to Absolute Salinity), using the 75-term equation.

gsw_rho_alpha_beta(SA, CT, p)

Arguments

SA

Absolute Salinity [ g/kg ]

CT

Conservative Temperature [ degC ]

p

sea pressure [dbar], i.e. absolute pressure [dbar] minus 10.1325 dbar

Value

A list containing in-situ density rho [ kg/m^3 ], thermal expansion coefficient alpha [ 1/degC ], and haline contraction coefficient beta [ kg/g ].

Implementation Note

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.

References

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

See also

Other things related to density: gsw_CT_from_rho(), gsw_CT_maxdensity(), gsw_SA_from_rho(), gsw_alpha_on_beta(), gsw_alpha_wrt_t_exact(), gsw_alpha_wrt_t_ice(), gsw_alpha(), gsw_beta_const_t_exact(), gsw_beta(), gsw_pot_rho_t_exact(), gsw_rho_first_derivatives_wrt_enthalpy(), gsw_rho_first_derivatives(), gsw_rho_ice(), gsw_rho_t_exact(), gsw_rho(), gsw_sigma0(), gsw_sigma1(), gsw_sigma2(), gsw_sigma3(), gsw_sigma4(), gsw_specvol_alpha_beta(), gsw_specvol_anom_standard(), gsw_specvol_ice(), gsw_specvol_t_exact(), gsw_specvol()

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_rho_alpha_beta(SA, CT, p)
stopifnot(all.equal(r$rho/1000, c(1.021839935738108, 1.022262457966867, 1.024427195413316,
                                  1.027790152759127, 1.029837779000189, 1.032002453224572)))
stopifnot(all.equal(r$alpha*1000, c(0.324638934509245, 0.322655537959731, 0.281145723210171,
                                    0.173199716344780, 0.146289673594824, 0.129414845334599)))
stopifnot(all.equal(r$beta*1000, c(0.717483987596135, 0.717647512290095, 0.726211643644768,
                                   0.750500751749777, 0.755052064788492, 0.757050813384370)))