gsw_CT_freezing

Conservative Temperature freezing point

Contents

USAGE:

CT_freezing = gsw_CT_freezing(SA,p,saturation_fraction)

DESCRIPTION:

Calculates the Conservative Temperature at which seawater freezes.  The 
Conservative Temperature freezing point is calculated from the exact 
in-situ freezing temperature which is found by a modified Newton-Raphson
iteration (McDougall and Wotherspoon, 2013) of the equality of the 
chemical potentials of water in seawater and in ice.
An alternative GSW function, gsw_CT_freezing_poly, it is based on a 
computationally-efficient polynomial, and is accurate to within -5e-4 K 
and 6e-4 K, when compared with this function.

INPUT:

SA  =  Absolute Salinity                                        [ g/kg ]
p   =  sea pressure                                             [ dbar ]
       ( i.e. absolute pressure - 10.1325 dbar )     
         
OPTIONAL:

saturation_fraction  =  the saturation fraction of dissolved air  
                        in seawater
(i.e., saturation_fraction must be between 0 and 1, and the 
default is 0, air free) 

p & saturation_fraction (if provided) may have dimensions 1x1 or Mx1
or 1xN or MxN, where SA is MxN.

OUTPUT:

CT_freezing = Conservative Temperature at freezing of seawater [ deg C ]
              That is, the freezing temperature expressed in
              terms of Conservative Temperature (ITS-90).

EXAMPLE:

SA = [34.7118; 34.8915; 35.0256; 34.8472; 34.7366; 34.7324;]
p =  [     10;      50;     125;     250;     600;    1000;]
saturation_fraction = 1;
CT_freezing = gsw_CT_freezing(SA,p,saturation_fraction)
CT_freezing =
  -1.899683776424096
  -1.940791867869104
  -2.006240664432488
  -2.092357761318778
  -2.359300831770506
  -2.677162675412748

AUTHOR:

Paul Barker, Trevor McDougall and Rainer Feistal   [ 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 section 3.3 of this TEOS-10 Manual.
McDougall, T.J. and S.J. Wotherspoon, 2013: A simple modification of 
 Newton’s method to achieve convergence of order "1 + sqrt(2)". Applied 
 Mathematics Letters, 29, 20-25.  
 http://dx.doi.org/10.1016/j.aml.2013.10.008 
The software is available from http://www.TEOS-10.org