# gsw_pt0_from_t

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

## Contents

## 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)".

## 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