# gsw_pt_from_CT

`potential temperature from Conservative Temperature`

## USAGE:

`pt = gsw_pt_from_CT(SA,CT)`

## DESCRIPTION:

```Calculates potential temperature (with a reference sea pressure of zero
dbar) from Conservative Temperature.  This function uses 1.5 iterations
through a modified Newton-Raphson (N-R) iterative solution proceedure,
starting from a rational-function-based initial condition for both pt
and dCT_dpt (McDougall and Wotherspoon, 2013).```
 ```Click for a more detailed description of calculating potential temperature from Conservative Temperature.```

## INPUT:

```SA   =   Absolute Salinity                                      [ g/kg ]
CT   =   Conservative Temperature                              [ deg C ]```
`SA & CT need to have the same dimensions.`

## OUTPUT:

```pt   =   potential temperature referenced to a sea             [ deg C ]
pressure of zero dbar (ITS-90)```

## EXAMPLE:

```SA = [34.7118; 34.8915; 35.0256; 34.8472; 34.7366; 34.7324;]
CT = [28.8099; 28.4392; 22.7862; 10.2262;  6.8272;  4.3236;]```
`pt = gsw_pt_from_CT(SA,CT)`
`pt =`
```   28.783177048624573
28.420955597191984
22.784953468087107
10.230534394434429
6.829216587061605
4.324534835990236```

## AUTHOR:

```Trevor McDougall, David Jackett, Claire Roberts-Thomson & 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 sections 3.1 and 3.3 of this TEOS-10 Manual.```
```McDougall, T.J., and S.J. Wotherspoon, 2014: A simple modification of
Newtonâ€™s method to achieve convergence of order "1 + sqrt(2)". Applied
Mathematics Letters, 29, 20-25.
http://dx.doi.org/10.1016/j.aml.2013.10.008 ```
`The software is available from http://www.TEOS-10.org`