# gsw_SA_from_rho

```Absolute Salinity from density
(75-term equation)```

## USAGE:

`SA = gsw_SA_from_rho(rho,CT,p)`

## DESCRIPTION:

```Calculates the Conservative Temperature of maximum density of seawater.
This function returns the Conservative Temperature at which the density
of seawater is a maximum, at given Absolute Salinity, SA, and sea
pressure, p (in dbar).  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 the 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". ``` ```Click for a more detailed description of calculating the Absolute Salinty from density.```

## INPUT:

```rho =  density of a seawater sample (e.g. 1026 kg/m^3)        [ kg/m^3 ]
Note. This input has not had 1000 kg/m^3 subtracted from it.
That is, it is 'density', not 'density anomaly'.
CT  =  Conservative Temperature (ITS-90)                       [ deg C ]
p   =  sea pressure                                             [ dbar ]
( i.e. absolute pressure - 10.1325 dbar )```
```rho & CT need to hve the same dimensions.
p may have dimensions 1x1 or Mx1 or 1xN or MxN, where SA is MxN.```

## OUTPUT:

`SA  =  Absolute Salinity                                        [ g/kg ]`

## EXAMPLE:

```rho = [1021.8482; 1022.2647; 1024.4207; 1027.7841; 1029.8287; 1031.9916;]
CT =  [ 28.7856;  28.4329;  22.8103;  10.2600;   6.8863;   4.4036;]
p =   [     10;      50;     125;     250;     600;    1000;]```
`SA = gsw_SA_from_rho(rho,CT,p)`
`SA =`
```  34.712080120418108
34.891723808488869
35.026202257609505
34.847160842234572
34.736398269039945
34.732228881079742```

## AUTHOR:

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

## VERSION NUMBER:

`3.05 (16th February, 2015)`

## 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.
See section 3.42 of this TEOS-10 Manual.```
```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.```
```Roquet, F., G. Madec, T.J. McDougall, P.M. Barker, 2015: Accurate
polynomial expressions for the density and specifc volume of seawater
using the TEOS-10 standard. Ocean Modelling.```
`The software is available from http://www.TEOS-10.org`