# gsw_SA_CT_from_sigma0_spiciness0

SA and CT from sigma and spiciness at p = 0 dbar (75-term equation)

## Contents

## USAGE:

[SA,CT] = gsw_SA_CT_from_sigma0_spiciness0(sigma0,spiciness0)

## DESCRIPTION:

Calculates the Absolute Salinity and the Conservative Temperature of a seawater sample at given values of potential density referenced to 0 dbar and spiciness0. This function uses the computationally-efficient 75-term expression for specific volume in terms of SA, CT and p (Roquet et al., 2015).

Note that this 75-term equation has been fitted in a restricted range of parameter space, and is most accurate inside the "oceanographic funnel" described in McDougall et al. (2003). The GSW library function "gsw_infunnel(SA,CT,p)" is avaialble to be used if one wants to test if some of one's data lies outside this "funnel".

## INPUT:

sigma0 = density anomaly of a seawater sample (e.g 26 kg/m^3) referenced to 0 dbar [ kg/m^3 ] Note. This input has had 1000 kg/m^3 subtracted from it. That is, it is 'density anomaly', not 'density'. spiciness0 = spiciness appropriate to 0 dbar, as given by the paper of McDougall and Krzysik (2015), and the GSW algorithm gsw_spiciness0(SA,CT) [ kg/m^3 ]

sigma0 and spiciness0 need to have the same dimensions.

## OUTPUT:

SA = Absolute Salinity. [ g/kg ] CT = Conservative Temperature (ITS-90) [ deg C ]

## EXAMPLE:

sigma0 = [21.7979; 22.0522; 23.8930; 26.6676; 27.1074; 27.4097;] spiciness0 = [ 5.7290; 5.7499; 4.1635; 1.0694; 0.4264; 0.0897;]

[SA,CT] = gsw_SA_CT_from_sigma0_spiciness0(sigma0,spiciness0)

SA =

34.711800450272577 34.891462385944791 35.025578083694874 34.847218272580029 34.736595459209234 34.732349892969246

CT =

28.809903466348750 28.439162940497393 22.786091646704868 10.226332048975316 6.827030481301175 4.323687506915744

## AUTHOR:

Trevor McDougall and Paul Barker [ help@teos-10.org ]

## VERSION NUMBER:

3.06.12 (2nd July, 2020)

## REFERENCES:

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. Available from the TEOS-10 web site.

McDougall, T.J., D.R. Jackett, D.G. Wright and R. Feistel, 2003: Accurate and computationally efficient algorithms for potential temperature and density of seawater.J. Atmosph. Ocean. Tech.,20, pp. 730-741.

McDougall, T.J., and O.A. Krzysik, 2015: Spiciness.Journal of Marine Research,73, 141-152.

Roquet, F., G. Madec, T.J. McDougall and P.M. Barker, 2015: Accurate polynomial expressions for the density and specific volume of seawater using the TEOS-10 standard.Ocean Modelling,90, pp. 29-43. http://dx.doi.org/10.1016/j.ocemod.2015.04.002

The software is available from http://www.TEOS-10.org