# gsw_pt0_from_t

```potential temperature with a reference
sea pressure of zero dbar```

## USAGE:

`pt0 = gsw_pt0_from_t(SA,t,p)`

## DESCRIPTION:

```Calculates potential temperature with reference pressure, pr = 0 dbar.
The present routine is computationally faster than the more general
function "gsw_pt_from_t(SA,t,p,pr)" which can be used for any reference
pressure value.  This routine calls the library functions
"gsw_entropy_part(SA,t,p)", "gsw_entropy_part_zerop(SA,pt0)" and
"gsw_gibbs_pt0_pt0(SA,pt0)".```
 ```Click for a more detailed description of potential temperature with a reference sea pressure of zero dbar.```

## INPUT:

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

## OUTPUT:

```pt0   =  potential temperature                                 [ deg C ]
with reference sea pressure (pr) = 0 dbar.
Note. The reference sea pressure of the output, pt0, is zero dbar.```

## 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;]```
`pt0 = gsw_pt0_from_t(SA,t,p)`
`pt0 =`
```  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`