# gsw_CT_from_enthalpy

    Conservative Temperature from specific enthalpy
    of seawater (75-term equation)

## Contents

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

## USAGE:

    CT  =  gsw_CT_from_enthalpy(SA,h,p)

## DESCRIPTION:

    Calculates the Conservative Temperature of seawater, given the Absolute
    Salinity, specific enthalpy, h, and pressure p.  The specific enthalpy
    input is the one calculated from the computationally-efficient 75-term
    expression for specific volume in terms of SA, CT and p (Roquet et al.,
    2015).

    Note that the 75-term equation has been fitted in a restricted range of
    parameter space, and is most accurate inside the "oceanographic funnel"
    described in  McDougall et al. (2003).  The GSW library function
    "gsw_infunnel(SA,CT,p)" is avaialble to be used if one wants to test if
    some of one's data lies outside this "funnel".

## INPUT:

    SA  =  Absolute Salinity                                        [ g/kg ]
    h   =  specific enthalpy                                        [ J/kg ]
    p   =  sea pressure                                             [ dbar ]
           ( i.e. absolute pressure - 10.1325 dbar )

    SA & h need to have the same dimensions.
    p may have dimensions 1x1 or Mx1 or 1xN or MxN, where SA & h are MxN.

## OUTPUT:

    CT  =  Conservative Temperature ( ITS-90)                      [ deg C ]

## EXAMPLE:

    SA = [34.7118; 34.8915; 35.0256; 34.8472; 34.7366; 34.7324;]
    h = [1.15103e5; 1.14014e5; 0.92180e5; 0.43255e5; 0.33087e5; 0.26970e5;]
    p =  [     10;      50;     125;     250;     600;    1000;]

    CT = gsw_CT_from_enthalpy(SA,h,p)

    CT =

      28.809854569021972
      28.439026483379287
      22.786196534098817
      10.226106994920777
       6.827159682675204
       4.323428660306681

## AUTHOR:

    Trevor McDougall 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.

    McDougall, T.J., D.R. Jackett, D.G. Wright and R. Feistel, 2003:
     Accurate and computationally efficient algorithms for potential
     temperature and density of seawater.  J. Atmosph. Ocean. Tech., 20,
     pp. 730-741.

    Roquet, F., G. Madec, T.J. McDougall, P.M. Barker, 2015: Accurate
     polynomial expressions for the density and specifc volume of seawater
     using the TEOS-10 standard. Ocean Modelling.

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