gsw_enthalpy_diff_CT25

difference of enthalpy between two pressures (25-term equation)

Contents

USAGE:

[enthalpy_diff, in_funnel] =
                          gsw_enthalpy_diff_CT25(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.  This
function uses the computationally-efficient 25-term expression for
density in terms of SA, CT and p (McDougall et al., 2010).  The output
(enthalpy_diff) is the specific enthalpy evaluated at (SA, CT, p_deep)
minus the specific enthalpy at (SA, CT, p_shallow).
TEOS-10
Click for a more detailed description of the difference
of enthalpy between two pressures, calculated with the
25-term equation.

INPUT:

SA         =  Absolute Salinity                                 [ g/kg ]
CT         =  Conservative Temperature                         [ deg C ]
p_shallow  =  upper sea pressure                                [ dbar ]
              (ie. shallower absolute pressure - 10.1325 dbar)
p_deep     =  lower sea pressure                                [ dbar ]
              (ie. 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  =  difference of specific enthalpy               [ J/kg ]
                                         (deep minus shallow)
in_funnel      =  0, if SA, CT and p are outside the "funnel"
               =  1, if SA, CT and p are inside the "funnel"
Note. The term "funnel" describes the range of SA, CT and p over which
  the error in the fit of the computationally-efficient 25-term
  expression for density was calculated (McDougall et al., 2010).

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_shallow =  [     10;      50;     125;     250;     600;    1000;]
p_deep    =  [    110;     150;     225;     350;     700;    1100;]
[enthalpy_diff, in_funnel] =  ...
                          gsw_enthalpy_diff_CT25(SA,CT,p_shallow,p_deep)
enthalpy_diff =                  in_funnel =
1.0e+002 *
 9.784262827561797                1
 9.780221873372307                1
 9.759531141438936                1
 9.727477253978700                1
 9.708128690308879                1
 9.687770260315075                1

AUTHOR:

 Trevor McDougall & Claire Roberts-Thomson.       [ 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 Eqns. (3.32.2) and (A.30.6) 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