# gsw_pt_from_t

`potential temperature`

## USAGE:

`pt = gsw_pt_from_t(SA,t,p,p_ref)`

## DESCRIPTION:

```Calculates potential temperature with the general reference pressure,
p_ref, from in-situ temperature, t.
This function calls "gsw_entropy_part" which evaluates entropy, except
for the parts which are a function of Absolute Salinity alone.```
 ```Click for a more detailed description of potential temperature.```

## INPUT:

```SA  =   Absolute Salinity                                       [ g/kg ]
t   =   in-situ temperature (ITS-90)                           [ deg C ]
p   =   sea pressure                                            [ dbar ]
( i.e. absolute pressure - 10.1325 dbar )```
```OPTIONAL:
p_ref = reference pressure                                      [ dbar ]
( i.e. absolute reference pressure - 10.1325 dbar )
(If reference pressure is not given then it is assumed that reference
pressure is zero).```
```SA & t need to have the same dimensions. p & pr (if provided) may
have dimensions 1x1 or Mx1 or 1xN or MxN, where SA & t are MxN.```
```A faster gsw routine exists if pr is indeed zero dbar, this routine
is "gsw_pt0_from_t(SA,t,p)".```

## OUTPUT:

```pt   =  potential temperature with                             [ deg C ]
reference pressure, p_ref. (ITS-90)```

## EXAMPLE:

```SA = [34.7118; 34.8915; 35.0256; 34.8472; 34.7366; 34.7324;]
t =  [28.7856; 28.4329; 22.8103; 10.2600;  6.8863;  4.4036;]
p =  [     10;      50;     125;     250;     600;    1000;]
p_ref = 0```
`pt = gsw_pt_from_t(SA,t,p,p_ref)`
`pt =`
```  28.783196819670632
28.420983342398962
22.784930399117108
10.230523661095731
6.829230224409661
4.324510571845719```

## AUTHOR:

```Trevor McDougall, David Jackett, Claire Roberts-Thomson 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 section 3.1 of this TEOS-10 Manual.```
`The software is available from http://www.TEOS-10.org`