Contents
USAGE:
[v_SA_wrt_h, v_h] = gsw_specvol_first_derivatives_wrt_enthalpy(SA,CT,p)
DESCRIPTION:
Calculates the following two first-order derivatives of specific
volume (v),
(1) v_SA_wrt_h, first-order derivative with respect to Absolute Salinity
at constant h & p.
(2) v_h, first-order derivative with respect to h at
constant SA & p.
This function uses 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 ]
CT = Conservative Temperature [ deg C ]
p = sea pressure [ dbar ]
(ie. absolute pressure - 10.1325 dbar)
SA & CT need to have the same dimensions.
p may have dimensions 1x1 or Mx1 or 1xN or MxN, where SA & CT are MxN.
OUTPUT:
v_SA_wrt_h = The first derivative of specific volume with respect to
Absolute Salinity at constant CT & p.
[ (m^3/kg)(g/kg)^-1 ]
v_h = The first derivative of specific volume with respect to
SA and CT at constant p. [ (m^3/kg)(J/kg)^-1 ]
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 = [ 10; 50; 125; 250; 600; 1000;]
[v_SA_wrt_h, v_h] = gsw_specvol_first_derivatives_wrt_enthalpy(SA,CT,p)
v_SA_wrt_h =
1.0e-06 *
-0.702143511679586
-0.701991101310494
-0.708834353735310
-0.730130919555592
-0.733018321892082
-0.733342002723321
v_h =
1.0e-10 *
0.795862623587769
0.790648383268264
0.687443468257647
0.422105846942233
0.355778874334799
0.314053366403993
AUTHOR:
Paul Barker and Trevor McDougall [ help@teos-10.org ]
VERSION NUMBER:
3.06.15 (1st June, 2022)
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 appendix A.20 and appendix K 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 and P.M. Barker, 2015: Accurate
polynomial expressions for the density and specific volume of seawater
using the TEOS-10 standard. Ocean Modelling, 90, pp. 29-43.
http://dx.doi.org/10.1016/j.ocemod.2015.04.002
The software is available from http://www.TEOS-10.org