## Contents

## USAGE:

pressure_freezing = gsw_pressure_freezing_CT(SA,CT,saturation_fraction)

## DESCRIPTION:

Calculates the pressure (in dbar) of seawater at the freezing
temperature. That is, the output is the pressure at which seawater,
with Absolute Salinity SA, Conservative Temperature CT, and with
saturation_fraction of dissolved air, freezes. If the input values are
such that there is no value of pressure in the range between 0 dbar and
10,000 dbar for which seawater is at the freezing temperature, the
output, pressure_freezing, is put equal to NaN.

## INPUT:

SA = Absolute Salinity [ g/kg ]
CT = Conservative Temperature (ITS-90) [ deg C ]
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 1, completely saturated)

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

## OUTPUT:

pressure_freezing = sea pressure at which the seawater [ dbar ]
freezes
( i.e. absolute pressure - 10.1325 dbar )

## EXAMPLE:

SA = [34.7118; 34.8915; 35.0256; 34.8472; 34.7366; 34.7324;]
CT = [-1.8996; -1.9407; -2.0062; -2.0923; -2.3593; -2.6771;]
saturation_fraction = [1; 0.8; 0.6; 0.5; 0.4; 0;]

pressure_freezing = gsw_pressure_freezing_CT(SA,CT,saturation_fraction)

pressure_freezing =

1.0e+003 *

0.009890530270710
0.050376026585933
0.125933117050624
0.251150973076077
0.601441775836021
1.002273338145043

## 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.

McDougall, T.J. and S.J. Wotherspoon, 2013: A simple modification of
Newtonâ€™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