The Gibbs SeaWater (GSW)
Oceanographic Toolbox of TEOS-10
Contents
- documentaion set
- Practical Salinty (SP), PSS-78
- Absolute Salinity (SA), Preformed Salinity (Sstar) and Conservative Temperature (CT)
- Absolute Salinity - Conservative Temperature plotting function
- other conversions between temperatures, salinities, entropy, pressure and height
- density and enthalpy, based on the 48-term expression for density
- water column properties, based on the 48-term expression for density
- neutral and non-linear properties, based on the 48-term expression for density
- geostrophic streamfunctions, based on the 48-term expression for density
- geostrophic velocity
- derivatives of enthalpy, entropy, CT and pt
- freezing temperatures
- isobaric melting enthalpy and isobaric evaporation enthalpy
- Planet Earth properties
- steric height
- TEOS-10 constants
- density and enthalpy in terms of CT, based on the exact Gibbs function
- basic thermodynamic properties in terms of in-situ temperature, based on the exact Gibbs function
- Library functions of the GSW toolbox (internal functions; not intended to be called by users)
- Licences and third party software
documentation set
gsw_front_page front page to the GSW Oceanographic Toolbox
gsw_check_functions checks that all the GSW functions work correctly
gsw_demo demonstrates many GSW functions and features
Practical Salinity (SP), PSS-78
gsw_SP_from_C Practical Salinity from conductivity, C (inc. for SP < 2)
gsw_C_from_SP conductivity, C, from Practical Salinity (inc. for SP < 2)
gsw_SP_from_R Practical Salinity from conductivity ratio, R (inc. for SP < 2)
gsw_R_from_SP conductivity ratio, R, from Practical Salinity (inc. for SP < 2)
gsw_SP_salinometer Practical Salinity from a laboratory salinometer (inc. for SP < 2)
gsw_SP_from_SK Practical Salinity from Knudsen Salinity
Absolute Salinity (SA), Preformed Salinity (Sstar) and Conservative Temperature (CT)
gsw_SA_from_SP Absolute Salinity from Practical Salinity
gsw_Sstar_from_SP Preformed Salinity from Practical Salinity
gsw_CT_from_t Conservative Temperature from in-situ temperature
Absolute Salinity - Conservative Temperature plotting function
gsw_SA_CT_plot function to plot Absolute Salinity - Conservative Temperature
profiles on the SA-CT diagram, including the freezing line
and selected potential density contours
other conversions between temperatures, salinities, pressure and height
gsw_deltaSA_from_SP Absolute Salinity Anomaly from Practical Salinity
gsw_SA_Sstar_from_SP Absolute Salinity & Preformed Salinity from Practical Salinity
gsw_SR_from_SP Reference Salinity from Practical Salinity
gsw_SP_from_SR Practical Salinity from Reference Salinity
gsw_SP_from_SA Practical Salinity from Absolute Salinity
gsw_Sstar_from_SA Preformed Salinity from Absolute Salinity
gsw_SA_from_Sstar Absolute Salinity from Preformed Salinity
gsw_SP_from_Sstar Practical Salinity from Preformed Salinity
gsw_pt_from_CT potential temperature from Conservative Temperature
gsw_t_from_CT in-situ temperature from Conservative Temperature
gsw_CT_from_pt Conservative Temperature from potential temperature
gsw_pot_enthalpy_from_pt potential enthalpy from potential temperature
gsw_pt0_from_t potential temperature with a reference pressure of zero dbar
gsw_pt_from_t potential temperature
gsw_t90_from_t48 ITS-90 temperature from IPTS-48 temperature
gsw_t90_from_t68 ITS-90 temperature from IPTS-68 temperature
gsw_z_from_p height from pressure
gsw_p_from_z pressure from height
gsw_depth_from_z depth from height
gsw_z_from_depth height from depth
gsw_Abs_Pressure_from_p Absolute Pressure,P, from pressure, p
gsw_p_from_Abs_Pressure pressure, p, from Absolute Pressure, P
gsw_entropy_from_CT entropy from Conservative Temperature
gsw_CT_from_entropy Conservative Temperature from entropy
gsw_entropy_from_pt entropy from potential temperature
gsw_pt_from_entropy potential temperature from entropy
gsw_molality_from_SA molality of seawater
gsw_ionic_strength_from_SA ionic strength of seawater
density and enthalpy, based on the 48-term expression for density
The functions in this group ending in "_CT" may also be called without "_CT".
gsw_rho_CT in-situ density from CT, and potential density
gsw_alpha_CT thermal expansion coefficient with respect to CT
gsw_beta_CT saline contraction coefficient at constant CT
gsw_rho_alpha_beta_CT in-situ density, thermal expansion & saline contraction coefficients
gsw_specvol_CT specific volume
gsw_specvol_anom_CT specific volume anomaly
gsw_sigma0_CT sigma0 from CT with reference pressure of 0 dbar
gsw_sigma1_CT sigma1 from CT with reference pressure of 1000 dbar
gsw_sigma2_CT sigma2 from CT with reference pressure of 2000 dbar
gsw_sigma3_CT sigma3 from CT with reference pressure of 3000 dbar
gsw_sigma4_CT sigma4 from CT with reference pressure of 4000 dbar
gsw_sound_speed_CT sound speed (approximate, with r.m.s. error of 0.067 m/s)
gsw_internal_energy_CT internal energy
gsw_enthalpy_CT enthalpy
gsw_enthalpy_diff_CT difference of enthalpy between two pressures
gsw_dynamic_enthalpy_CT dynamic enthalpy
gsw_SA_from_rho_CT Absolute Salinity from density & CT
gsw_CT_from_rho Conservative Temperature from density
gsw_CT_maxdensity Conservative Temperature of maximum density of seawater
water column properties, based on the 48-term expression for density
gsw_Nsquared buoyancy (Brunt-Vaisala) frequency squared (N^2)
gsw_Turner_Rsubrho Turner angle & Rsubrho
gsw_IPV_vs_fNsquared_ratio ratio of the vertical gradient of potential density
(with reference pressure, p_ref), to the vertical gradient
of locally-referenced potential density
neutral and non-linear properties, based on the 48-term expression for density
gsw_cabbeling cabbeling coefficient
gsw_thermobaric thermobaric coefficient
gsw_isopycnal_slope_ratio ratio of the slopes of isopycnals on the SA-CT diagram
for p & p_ref
gsw_isopycnal_vs_ntp_CT_ratio ratio of the gradient of Conservative Temperature
in a potential density surface to that in the neutral
tangent plane
gsw_ntp_pt_vs_CT_ratio ratio of gradients of potential temperature &
Conservative Temperature in a neutral tangent plane
(i.e. in a locally-referenced potential density surface)
geostrophic streamfunctions, based on the 48-term expression for density
gsw_geo_strf_dyn_height dynamic height anomaly
gsw_geo_strf_dyn_height_pc dynamic height anomaly for piecewise constant profiles
gsw_geo_strf_isopycnal approximate isopycnal geostrophic streamfunction
gsw_geof_str_isopycnal_pc approximate isopycnal geostrophic streamfunction for
piecewise constant profiles
gsw_geo_strf_Montgomery Montgomery geostrophic streamfunction
gsw_geo_strf_Cunningham Cunningham geostrophic streamfunction
geostrophic velocity
gsw_geostrophic_velocity geostrophic velocity
derivatives of enthalpy, entropy, CT and pt
gsw_CT_first_derivatives first derivatives of Conservative Temperature
gsw_CT_second_derivatives second derivatives of Conservative Temperature
gsw_enthalpy_first_derivatives first derivatives of enthalpy
gsw_enthalpy_second_derivatives second derivatives of enthalpy
gsw_entropy_first_derivatives first derivatives of entropy
gsw_entropy_second_derivatives second derivatives of entropy
gsw_pt_first_derivatives first derivatives of potential temperature
gsw_pt_second_derivatives second derivatives of potential temperature
freezing temperatures
gsw_CT_freezing Conservative Temperature freezing temperature of seawater
gsw_t_freezing in-situ freezing temperature of seawater
gsw_brineSA_CT Absolute Salinity of seawater at the freezing point (for given CT)
gsw_brineSA_t Absolute Salinity of seawater at the freezing point (for given t)
isobaric melting enthalpy and isobaric evaporation enthalpy
gsw_latentheat_melting latent heat of melting of ice into seawater (isobaric melting enthalpy)
gsw_latentheat_evap_CT latent heat of evaporation of water from seawater (isobaric
evaporation enthalpy) with CT as input temperature
gsw_latentheat_evap_t latent heat of evaporation of water from seawater (isobaric
evaporation enthalpy) with in-situ temperature, t, as input
Planet Earth properties
gsw_f Coriolis parameter
gsw_grav gravitational acceleration
gsw_distance spherical earth distance between points in the ocean
steric height
gsw_steric_height dynamic height anomaly divided by 9.7963 m s^-2
TEOS-10 constants
gsw_T0 Celcius zero point; 273.15 K
gsw_P0 one standard atmosphere; 101 325 Pa
gsw_SS0 Standard Ocean Reference Salinity; 35.165 04 g/kg
gsw_uPS unit conversion factor for salinities; (35.165 04/35) g/kg
gsw_cp0 the "specific heat" for use with CT; 3991.867 957 119 63 (J/kg)/K
gsw_C3515 conductivity of SSW at SP=35, t_68=15, p=0; 42.9140 mS/cm
gsw_SonCl ratio of SP to Chlorinity; 1.80655 (g/kg)^-1
gsw_valence_factor valence factor of sea salt; 1.2452898
gsw_atomic_weight mole-weighted atomic weight of sea salt; 31.4038218... g/mol
density and enthalpy in terms of CT, based on the exact Gibbs function
gsw_rho_CT_exact in-situ density from CT, and potential density from CT
gsw_alpha_CT_exact thermal expansion coefficient with respect to CT
gsw_beta_CT_exact saline contraction coefficientat constant CT
gsw_rho_alpha_beta_CT_exact in-situ density, thermal expansion & saline contraction coefficient from CT
gsw_specvol_CT_exact specific volume from CT
gsw_specvol_anom_CT_exact specific volume anomaly from CT
gsw_sigma0_CT_exact sigma0 from CT with reference pressure of 0 dbar
gsw_sigma1_CT_exact sigma1 from CT with reference pressure of 1000 dbar
gsw_sigma2_CT_exact sigma2 from CT with reference pressure of 2000 dbar
gsw_sigma3_CT_exact sigma3 from CT with reference pressure of 3000 dbar
gsw_sigma4_CT_exact sigma4 from CT with reference pressure of 4000 dbar
gsw_sound_speed_CT_exact sound speed
gsw_internal_energy_CT_exact internal energy
gsw_enthalpy_CT_exact enthalpy from CT
gsw_enthalpy_diff_CT_exact difference of enthalpy from CT between two pressures
gsw_dynamic_enthalpy_CT_exact dynamic enthalpy from CT
gsw_SA_from_rho_CT_exact Absolute Salinity from Density & CT
gsw_CT_from_rho_exact Conservative Temperature from density
gsw_CT_maxdensity_exact Conservative Temperature of maximum density of seawater
basic thermodynamic properties in terms of in-situ t, based on the exact Gibbs function
gsw_rho_t_exact in-situ density
gsw_pot_rho_t_exact potential density
gsw_sigma0_pt0_exact sigma0 from pt0 with reference pressure of 0 dbar
gsw_alpha_wrt_CT_t_exact thermal expansion coefficient with respect to Conservative Temperature.
gsw_alpha_wrt_pt_t_exact thermal expansion coefficient with respect to potential temperature
gsw_alpha_wrt_t_exact thermal expansion coefficient with respect to in-situ temperature
gsw_beta_const_CT_t_exact saline contraction coefficient at constant Conservative Temperature.
gsw_beta_const_pt_t_exact saline contraction coefficient at constant potential temperature
gsw_beta_const_t_exact saline contraction coefficient at constant in-situ temperature
gsw_specvol_t_exact specific volume
gsw_specvol_anom_t_exact specific volume anomaly
gsw_sound_speed_t_exact sound speed
gsw_kappa_t_exact isentropic compressibility
gsw_kappa_const_t_exact isothermal compressibility
gsw_internal_energy_t_exact internal energy
gsw_enthalpy_t_exact enthalpy
gsw_dynamic_enthalpy_t_exact dynamic enthalpy
gsw_SA_from_rho_t_exact Absolute Salinity from density
gsw_t_from_rho_exact in-situ temperature from density
gsw_t_maxdensity_exact in-situ temperature of maximum density of seawater
gsw_entropy_t_exact entropy
gsw_cp_t_exact isobaric heat capacity
gsw_isochoric_heat_cap_t_exact isochoric heat capacity
gsw_chem_potential_relative_t_exact relative chemical potential
gsw_chem_potential_water_t_exact chemical potential of water in seawater
gsw_chem_potential_salt_t_exact chemical potential of salt in seawater
gsw_Helmholtz_energy_t_exact Helmholtz energy
gsw_adiabatic_lapse_rate_t_exact adiabatic lapse rate
gsw_osmotic_coefficient_t_exact osmotic coefficient of seawater
gsw_osmotic_pressure_t_exact osmotic pressure of seawater
Library functions of the GSW toolbox (internal functions; not intended to be called by users)
The GSW functions above call the following library functions.
gsw_gibbs the TEOS-10 Gibbs function and its derivatives
gsw_SAAR Absolute Salinity Anomaly Ratio (excluding the Baltic Sea)
gsw_Fdelta ratio of Absolute to Preformed Salinity, minus 1
gsw_delta_SA_ref Absolute Salinity Anomaly ref. value (excluding the Baltic Sea)
gsw_SA_from_SP_Baltic Calculates Absolute Salinity in the Baltic Sea
gsw_SP_from_SA_Baltic Calculates Practical Salinity in the Baltic Sea
gsw_infunnel "oceanographic funnel" check for the 25-term equation
gsw_entropy_part entropy minus the terms that are a function of only SA
gsw_entropy_part_zerop entropy_part evaluated at 0 dbar
gsw_interp_ref_cast linearly interpolates the reference cast
gsw_interp_SA_CT linearly interpolates (SA,CT,p) to the desired p
gsw_gibbs_pt0_pt0 gibbs(0,2,0,SA,t,0)
gsw_specvol_SSO_0_p specvol_CT(35.16504,0,p)
gsw_enthalpy_SSO_0_p enthalpy_CT(35.16504,0,p)
gsw_Hill_ratio_at_SP2 Hill ratio at a Practical Salinity of 2
The GSW data set.
gsw_data_v3_0 contains
(1) the global data set of Absolute Salinity Anomaly Ratio,
(2) the global data set of Absolute Salinity Anomaly Ref.,
(3) a reference cast (for the isopycnal streamfunction),
(4) two reference casts that are used by gsw_demo
(5) three vertical profiles of (SP, t, p) at known long & lat, plus
the outputs of all the GSW functions for these 3 profiles, and
the required accuracy of all these outputs.
Licences and 3rd party software
gsw_licence creative commons licence for the GSW Oceanographic Toolbox
cprintf prints colour text to the screen (third part software)
cprintf_licence licence for cprintf software