# gsw_kappa

`isentropic compressibility (75-term equation)`

## USAGE:

`kappa = gsw_kappa(SA,CT,p)`

## DESCRIPTION:

```Calculates the isentropic compressibility of seawater using 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 isentropic compressibility.```

## INPUT:

```SA  =  Absolute Salinity                                        [ g/kg ]
CT  =  Conservative Temperature (ITS-90)                       [ deg C ]
p   =  sea pressure                                             [ dbar ]
( ie. absolute pressure - 10.1325 dbar )```
```SA & CT need to have the same dimensions.
p may have dimensions 1x1 or Mx1 or 1xN or MxN, where SA & CT are MxN.```

## OUTPUT:

```kappa_CT_exact  =  Isentropic compressibility                   [ 1/Pa ]
Note. The output units are 1/Pa not 1/dbar.```

## EXAMPLE:

```SA = [34.7118; 34.8915; 35.0256; 34.8472; 34.7366; 34.7324;]
CT =  [28.7856; 28.4329; 22.8103; 10.2600;  6.8863;  4.4036;]
p =  [     10;      50;     125;     250;     600;    1000;]```
`kappa = gsw_kappa(SA,CT,p)`
`kappa =`
`1.0e-009 *`
```   0.411343648791300
0.411105416128094
0.416566236026610
0.435588650838751
0.438782500588955
0.439842289994702```

## AUTHOR:

`Trevor McDougall and 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 Eqns. (2.16.1) and the row for kappa in Table P.1 of appendix P
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`