gsw (version 1.0-5)

gsw_sigma4: Potential density anomaly referenced to 4000 dbar

Description

This uses the 75-term density equation, and returns potential density referenced to a pressure of 4000 dbar, minus 1000 kg/m^3.

Usage

gsw_sigma4(SA, CT)

Arguments

SA

Absolute Salinity [ g/kg ]

CT

Conservative Temperature [ degC ]

Value

potential density anomaly with reference pressure 4000 dbar [ kg/m^3 ]

Details

The present R function works with a wrapper to a C function contained within the GSW-C system (Version 3.05-4 dated 2017-08-07, available at https://github.com/TEOS-10/GSW-C, as git commit '5b4d959e54031f9e972f3e863f63e67fa4f5bfec'), which stems from the GSW-Fortran system (https://github.com/TEOS-10/GSW-Fortran) which in turn stems from the GSW-Matlab system (https://github.com/TEOS-10/GSW-Matlab). Consult http://www.teos-10.org to learn more about these software systems, their authorships, and the science behind it all.

References

http://www.teos-10.org/pubs/gsw/html/gsw_sigma4.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_alpha_beta, 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_specvol_alpha_beta, gsw_specvol_anom_standard, gsw_specvol_ice, gsw_specvol_t_exact, gsw_specvol

Examples

# NOT RUN {
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)
sigma4 <- gsw_sigma4(SA,CT)
expect_equal(sigma4, c(37.900374609834898, 38.166979617032439, 40.280876075282549,
                       43.896091033421953, 44.631677245327637, 45.171817312020039))
# }