Contents
USAGE:
enthalpy_diff = gsw_enthalpy_diff(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 75-term expression for
specific volume in terms of SA, CT and p (Roquet et al., 2015). 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 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 ]
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)
EXAMPLE:
SA = [34.7118; 34.8915; 35.0256; 34.8472; 34.7366; 34.7324;]
CT = [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 = gsw_enthalpy_diff(SA,CT,p_shallow,p_deep)
enthalpy_diff =
1.0e+002 *
9.784180644568052
9.780195056105020
9.759587700515114
9.727552719534447
9.708223170174454
9.687871289079633
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) and (A.30.6) of this TEOS-10 Manual.
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