def rho_CT_exact(SA, CT, p):
r"""Calculates in-situ density from Absolute Salinity and Conservative
Temperature.
Parameters
----------
SA : array_like
Absolute Salinity [g/kg]
CT : array_like
Conservative Temperature [:math:`^\circ` C (ITS-90)]
p : array_like
sea pressure [dbar]
Returns
-------
rho_CT_exact : array_like
in-situ density [kg/m**3]
See Also
--------
TODO
Notes
-----
The potential density with respect to reference pressure, p_ref, is
obtained by calling this function with the pressure argument being p_ref
(i.e. "rho_CT_exact(SA, CT, p_ref)"). This function uses the full Gibbs
function. There is an alternative to calling this function, namely
rho_CT(SA, CT, p), which uses the computationally efficient 48-term
expression for density in terms of SA, CT and p (McDougall et al., 2011).
Examples
--------
TODO
References
----------
.. [1] IOC, SCOR and IAPSO, 2010: The international thermodynamic equation
of seawater - 2010: Calculation and use of thermodynamic properties.
Intergovernmental Oceanographic Commission, Manuals and Guides No. 56,
UNESCO (English), 196 pp. See Eqn. (2.8.2).
.. [2] McDougall T.J., P.M. Barker, R. Feistel and D.R. Jackett, 2011: A
computationally efficient 48-term expression for the density of
seawater in terms of Conservative Temperature, and related properties
of seawater.
Modifications:
2011-04-03. Trevor McDougall and Paul Barker.
"""
t = t_from_CT(SA, CT, p)
return rho_t_exact(SA, t, p)
def rho_alpha_beta_CT_exact(SA, CT, p):
r"""Calculates in-situ density, the appropriate thermal expansion
coefficient and the appropriate saline contraction coefficient of seawater
from Absolute Salinity and Conservative Temperature.
See the individual functions rho_CT_exact, alpha_CT_exact, and
beta_CT_exact. Retained for compatibility with the Matlab GSW toolbox.
"""
t = t_from_CT(SA, CT, p)
rho_CT_exact = rho_t_exact(SA, t, p)
alpha_CT_exact = alpha_wrt_CT_t_exact(SA, t, p)
beta_CT_exact = beta_const_CT_t_exact(SA, t, p)
return rho_CT_exact, alpha_CT_exact, beta_CT_exact
def sigma4_CT_exact(SA, CT):
r"""Calculates potential density anomaly with reference pressure of
4000 dbar."""
t = t_from_CT(SA, CT, 4000.)
return rho_t_exact(SA, t, 4000.) - 1000
