Density
Functions related to density and specific volume.
These are a subset of the TEOS-10 table category “specific volume, density, and enthalpy”.
We are grouping the functions related to enthalpy and internal energy in their own “energy” module.
- gsw.density.alpha(SA, CT, p)[source]
Calculates the thermal expansion coefficient of seawater with respect to Conservative Temperature using the computationally-efficient expression for specific volume in terms of SA, CT and p (Roquet et al., 2015).
- Parameters
- SAarray-like
Absolute Salinity, g/kg
- CTarray-like
Conservative Temperature (ITS-90), degrees C
- parray-like
Sea pressure (absolute pressure minus 10.1325 dbar), dbar
- Returns
- alphaarray-like, 1/K
thermal expansion coefficient with respect to Conservative Temperature
- gsw.density.alpha_on_beta(SA, CT, p)[source]
Calculates alpha divided by beta, where alpha is the thermal expansion coefficient and beta is the saline contraction coefficient of seawater from Absolute Salinity and Conservative Temperature. This function uses the computationally-efficient expression for specific volume in terms of SA, CT and p (Roquet et al., 2015).
- Parameters
- SAarray-like
Absolute Salinity, g/kg
- CTarray-like
Conservative Temperature (ITS-90), degrees C
- parray-like
Sea pressure (absolute pressure minus 10.1325 dbar), dbar
- Returns
- alpha_on_betaarray-like, kg g^-1 K^-1
thermal expansion coefficient with respect to Conservative Temperature divided by the saline contraction coefficient at constant Conservative Temperature
- gsw.density.beta(SA, CT, p)[source]
Calculates the saline (i.e. haline) contraction coefficient of seawater at constant Conservative Temperature using the computationally-efficient 75-term expression for specific volume in terms of SA, CT and p (Roquet et al., 2015).
- Parameters
- SAarray-like
Absolute Salinity, g/kg
- CTarray-like
Conservative Temperature (ITS-90), degrees C
- parray-like
Sea pressure (absolute pressure minus 10.1325 dbar), dbar
- Returns
- betaarray-like, kg/g
saline contraction coefficient at constant Conservative Temperature
- gsw.density.kappa(SA, CT, p)[source]
Calculates the isentropic compressibility of seawater. This function has inputs of Absolute Salinity and Conservative Temperature. This function uses the computationally-efficient expression for specific volume in terms of SA, CT and p (Roquet et al., 2015).
- Parameters
- SAarray-like
Absolute Salinity, g/kg
- CTarray-like
Conservative Temperature (ITS-90), degrees C
- parray-like
Sea pressure (absolute pressure minus 10.1325 dbar), dbar
- Returns
- kappaarray-like, 1/Pa
isentropic compressibility of seawater
- gsw.density.rho(SA, CT, p)[source]
Calculates in-situ density from Absolute Salinity and Conservative Temperature, using the computationally-efficient expression for specific volume in terms of SA, CT and p (Roquet et al., 2015).
- Parameters
- SAarray-like
Absolute Salinity, g/kg
- CTarray-like
Conservative Temperature (ITS-90), degrees C
- parray-like
Sea pressure (absolute pressure minus 10.1325 dbar), dbar
- Returns
- rhoarray-like, kg/m
in-situ density
- gsw.density.rho_alpha_beta(SA, CT, p)[source]
Calculates in-situ density, the appropriate thermal expansion coefficient and the appropriate saline contraction coefficient of seawater from Absolute Salinity and Conservative Temperature. This function uses the computationally-efficient expression for specific volume in terms of SA, CT and p (Roquet et al., 2015).
- Parameters
- SAarray-like
Absolute Salinity, g/kg
- CTarray-like
Conservative Temperature (ITS-90), degrees C
- parray-like
Sea pressure (absolute pressure minus 10.1325 dbar), dbar
- Returns
- rhoarray-like, kg/m
in-situ density
- alphaarray-like, 1/K
thermal expansion coefficient with respect to Conservative Temperature
- betaarray-like, kg/g
saline (i.e. haline) contraction coefficient at constant Conservative Temperature
- gsw.density.rho_t_exact(SA, t, p)[source]
Calculates in-situ density of seawater from Absolute Salinity and in-situ temperature. Note that the output, rho, is density, not density anomaly; that is, 1000 kg/m^3 is not subtracted from it.
- Parameters
- SAarray-like
Absolute Salinity, g/kg
- tarray-like
In-situ temperature (ITS-90), degrees C
- parray-like
Sea pressure (absolute pressure minus 10.1325 dbar), dbar
- Returns
- rho_t_exactarray-like, kg/m^3
in-situ density (not density anomaly)
- gsw.density.sigma0(SA, CT)[source]
Calculates potential density anomaly with reference pressure of 0 dbar, this being this particular potential density minus 1000 kg/m^3. This function has inputs of Absolute Salinity and Conservative Temperature. This function uses the computationally-efficient expression for specific volume in terms of SA, CT and p (Roquet et al., 2015).
- Parameters
- SAarray-like
Absolute Salinity, g/kg
- CTarray-like
Conservative Temperature (ITS-90), degrees C
- Returns
- sigma0array-like, kg/m^3
potential density anomaly with respect to a reference pressure of 0 dbar, that is, this potential density - 1000 kg/m^3.
- gsw.density.sigma1(SA, CT)[source]
Calculates potential density anomaly with reference pressure of 1000 dbar, this being this particular potential density minus 1000 kg/m^3. This function has inputs of Absolute Salinity and Conservative Temperature. This function uses the computationally-efficient expression for specific volume in terms of SA, CT and p (Roquet et al., 2015).
- Parameters
- SAarray-like
Absolute Salinity, g/kg
- CTarray-like
Conservative Temperature (ITS-90), degrees C
- Returns
- sigma1array-like, kg/m^3
potential density anomaly with respect to a reference pressure of 1000 dbar, that is, this potential density - 1000 kg/m^3.
- gsw.density.sigma2(SA, CT)[source]
Calculates potential density anomaly with reference pressure of 2000 dbar, this being this particular potential density minus 1000 kg/m^3. Temperature. This function uses the computationally-efficient expression for specific volume in terms of SA, CT and p (Roquet et al., 2015).
- Parameters
- SAarray-like
Absolute Salinity, g/kg
- CTarray-like
Conservative Temperature (ITS-90), degrees C
- Returns
- sigma2array-like, kg/m^3
potential density anomaly with respect to a reference pressure of 2000 dbar, that is, this potential density - 1000 kg/m^3.
- gsw.density.sigma3(SA, CT)[source]
Calculates potential density anomaly with reference pressure of 3000 dbar, this being this particular potential density minus 1000 kg/m^3. Temperature. This function uses the computationally-efficient expression for specific volume in terms of SA, CT and p (Roquet et al., 2015).
- Parameters
- SAarray-like
Absolute Salinity, g/kg
- CTarray-like
Conservative Temperature (ITS-90), degrees C
- Returns
- sigma3array-like, kg/m^3
potential density anomaly with respect to a reference pressure of 3000 dbar, that is, this potential density - 1000 kg/m^3.
- gsw.density.sigma4(SA, CT)[source]
Calculates potential density anomaly with reference pressure of 4000 dbar, this being this particular potential density minus 1000 kg/m^3. Temperature. This function uses the computationally-efficient expression for specific volume in terms of SA, CT and p (Roquet et al., 2015).
- Parameters
- SAarray-like
Absolute Salinity, g/kg
- CTarray-like
Conservative Temperature (ITS-90), degrees C
- Returns
- sigma4array-like, kg/m^3
potential density anomaly with respect to a reference pressure of 4000 dbar, that is, this potential density - 1000 kg/m^3.
- gsw.density.sound_speed(SA, CT, p)[source]
Calculates the speed of sound in seawater. This function has inputs of Absolute Salinity and Conservative Temperature. This function uses the computationally-efficient expression for specific volume in terms of SA, CT and p (Roquet et al., 2015).
- Parameters
- SAarray-like
Absolute Salinity, g/kg
- CTarray-like
Conservative Temperature (ITS-90), degrees C
- parray-like
Sea pressure (absolute pressure minus 10.1325 dbar), dbar
- Returns
- sound_speedarray-like, m/s
speed of sound in seawater
- gsw.density.specvol(SA, CT, p)[source]
Calculates specific volume from Absolute Salinity, Conservative Temperature and pressure, using the computationally-efficient 75-term polynomial expression for specific volume (Roquet et al., 2015).
- Parameters
- SAarray-like
Absolute Salinity, g/kg
- CTarray-like
Conservative Temperature (ITS-90), degrees C
- parray-like
Sea pressure (absolute pressure minus 10.1325 dbar), dbar
- Returns
- specvolarray-like, m^3/kg
specific volume
- gsw.density.specvol_alpha_beta(SA, CT, p)[source]
Calculates specific volume, the appropriate thermal expansion coefficient and the appropriate saline contraction coefficient of seawater from Absolute Salinity and Conservative Temperature. This function uses the computationally-efficient expression for specific volume in terms of SA, CT and p (Roquet et al., 2015).
- Parameters
- SAarray-like
Absolute Salinity, g/kg
- CTarray-like
Conservative Temperature (ITS-90), degrees C
- parray-like
Sea pressure (absolute pressure minus 10.1325 dbar), dbar
- Returns
- specvolarray-like, m/kg
specific volume
- alphaarray-like, 1/K
thermal expansion coefficient with respect to Conservative Temperature
- betaarray-like, kg/g
saline (i.e. haline) contraction coefficient at constant Conservative Temperature
- gsw.density.specvol_anom_standard(SA, CT, p)[source]
Calculates specific volume anomaly from Absolute Salinity, Conservative Temperature and pressure. It uses the computationally-efficient expression for specific volume as a function of SA, CT and p (Roquet et al., 2015). The reference value to which the anomaly is calculated has an Absolute Salinity of SSO and Conservative Temperature equal to 0 degrees C.
- Parameters
- SAarray-like
Absolute Salinity, g/kg
- CTarray-like
Conservative Temperature (ITS-90), degrees C
- parray-like
Sea pressure (absolute pressure minus 10.1325 dbar), dbar
- Returns
- specvol_anomarray-like, m^3/kg
specific volume anomaly