## Contents

## USAGE:

[CTfreezing_SA, CTfreezing_P] = gsw_CT_freezing_first_derivatives(SA,p,saturation_fraction)

## DESCRIPTION:

Calculates the frist derivatives of the Conservative Temperature at
which seawater freezes, with respect to Absolute Salinity SA and
pressure P (in Pa).

## 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:

CTfreezing_SA = the derivative of the Conservative Temperature at
freezing (ITS-90) with respect to Absolute Salinity at
fixed pressure [ K/(g/kg) ] i.e. [ K kg/g ]
CTfreezing_P = the derivative of the Conservative Temperature at
freezing (ITS-90) with respect to pressure (in Pa) at
fixed Absolute Salinity [ K/Pa ]

## EXAMPLE:

SA = [34.7118; 34.8915; 35.0256; 34.8472; 34.7366; 34.7324;]
p = [ 10; 50; 125; 250; 600; 1000;]
saturation_fraction = [1; 0.8; 0.6; 0.5; 0.4; 0;]

[CTfreezing_SA, CTfreezing_P] = gsw_CT_freezing_first_derivatives(SA,p,saturation_fraction)

CTfreezing_SA =

-0.058193253897272
-0.058265158334170
-0.058345661671901
-0.058373842446463
-0.058534544740846
-0.058730846361252

CTfreezing_P =

1.0e-007 *

-0.765300390432684
-0.766942996466485
-0.769892679988284
-0.774561011527902
-0.787769143040504
-0.802771548245855

## AUTHOR:

Trevor McDougall & 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.

McDougall, T.J., P.M. Barker, R. Feistel and B.K. Galton-Fenzi, 2014:
Melting of Ice and Sea Ice into Seawater and Frazil Ice Formation.
Journal of Physical Oceanography, 44, 1751-1775.

The software is available from http://www.TEOS-10.org