# gsw_pt_from_CT

    potential temperature from Conservative Temperature

## Contents

- USAGE:
- DESCRIPTION:
- INPUT:
- OUTPUT:
- EXAMPLE:
- AUTHOR:
- VERSION NUMBER:
- REFERENCES:

## 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.

    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 and Paul Barker.
                                                      [ help_gsw@csiro.au ]

## VERSION NUMBER:

    2.0 (26th August, 2010)

## 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., D. R. Jackett, P. M. Barker, C. Roberts-Thomson, R.
     Feistel and R. W. Hallberg, 2010:  A computationally efficient 25-term
     expression for the density of seawater in terms of Conservative
     Temperature, and related properties of seawater.  To be submitted
     to Ocean Science Discussions.

    The software is available from http://www.TEOS-10.org