## Contents

## USAGE:

enthalpy_diff_CT_exact = gsw_enthalpy_diff_CT_exact(SA,CT,p_shallow,p_deep)

## DESCRIPTION:

Calculates the difference of the specific enthalpy of seawater between
two different pressures, p_deep (the deeper pressure) and p_shallow
(the shallower pressure), at the same values of SA and CT. The output
(enthalpy_diff) is the specific enthalpy evaluated at (SA,CT,p_deep)
minus the specific enthalpy at (SA,CT,p_shallow).

Note that this function uses the full Gibbs function. There is an
alternative to calling this function, namely
gsw_enthalpy_diff(SA,CT,p_shallow,p_deep), which uses the computationally
efficient 75-term expression for specific volume in terms of SA, CT and
p (Roquet et al., 2015).

## INPUT:

SA = Absolute Salinity [ g/kg ]
CT = Conservative Temperature [ deg C ]
p_shallow = upper sea pressure [ dbar ]
( i.e. shallower absolute pressure - 10.1325 dbar )
p_deep = lower sea pressure [ dbar ]
( i.e. deeper absolute pressure - 10.1325 dbar )

p_shallow and p_deep may have dimensions Mx1 or 1xN or MxN,
where SA and CT are MxN.

## OUTPUT:

enthalpy_diff_CT_exact = difference of specific enthalpy [ J/kg ]
(deep minus shallow)

## 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;]
p_shallow = [ 10; 50; 125; 250; 600; 1000;]
p_deep = [ 110; 150; 225; 350; 700; 1100;]

enthalpy_diff_CT_exact = gsw_enthalpy_diff_CT_exact(SA,CT,p_shallow,p_deep)

enthalpy_diff_CT_exact =

1.0e+002 *

9.784255933006788
9.780212984387035
9.759516776633390
9.727494888619550
9.708138965635516
9.687770207718350

## 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.
See Eqns. (3.32.2) of this TEOS-10 Manual.

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