Contents
USAGE:
[SA_final, CT_final] = ...
gsw_melting_seaice_into_seawater(SA,CT,p,saturation_fraction,w_seaice,SA_seaice,t_seaice)
DESCRIPTION:
Calculates the Absolute Salinity and Conservative Temperature that
results when a given mass of sea ice (or ice) melts and is mixed into a
known mass of seawater (whose properties are (SA,CT,p)).
If the ice contains no salt (e.g. if it is of glacial origin), then the
input 'SA_seaice' should be set to zero.
Ice formed at the sea surface (sea ice) typically contains between 2 g/kg
and 12 g/kg of salt (defined as the mass of salt divided by the mass of
ice Ih plus brine) and this programme returns NaN's if the input
SA_seaice is greater than 15 g/kg. If the SA_seaice input is not zero,
usually this would imply that the pressure p should be zero, as sea ice
only occurs near the sea surface. The code does not impose that p = 0
if SA_seaice is non-zero. Rather, this is left to the user.
The Absolute Salinity, SA_brine, of the brine trapped in little pockets
in the sea ice, is in thermodynamic equilibrium with the ice Ih that
surrounds these pockets. As the sea ice temperature, t_seaice, may be
less than the freezing temperature, SA_brine is usually greater than the
Absolute Salinity of the seawater at the time and place when and where
the sea ice was formed. So usually SA_brine will be larger than SA.
INPUT:
SA = Absolute Salinity of seawater [ g/kg ]
CT = Conservative Temperature of seawater (ITS-90) [ deg C ]
p = sea pressure [ dbar ]
( i.e. absolute pressure - 10.1325 dbar )
saturation_fraction = the saturation fraction of dissolved air in
seawater. saturation_fraction must be between 0 and 1.
w_seaice = mass fraction of sea ice, that is the mass of sea ice
divided by the sum of the masses of sea ice and seawater.
That is, the mass of sea ice divided by the mass of the
final mixed fluid. w_seaice must be between 0 and 1.
[ unitless ]
SA_seaice = Absolute Salinity of sea ice, that is, the mass fraction of
salt in sea ice, expressed in g of salt per kg of sea ice.
[ g/kg ]
t_seaice = the in-situ temperature of the sea ice (or ice) (ITS-90)
[ deg C ]
SA, CT, w_seaice, SA_seaice & t_seaice must all have the same dimensions.
p may have dimensions 1x1 or Mx1 or 1xN or MxN, where SA, CT, w_seaice,
SA_seaice and t_seaice are MxN.
OUTPUT:
SA_final = Absolute Salinity of the mixture of the melted sea ice
(or ice) and the orignal seawater [ g/kg ]
CT_final = Conservative Temperature of the mixture of the melted
sea ice (or ice) and the orignal seawater [ deg C ]
EXAMPLE:
SA = [34.7118; 34.8915; 35.0256; 34.8472; 34.7366; 34.7324;]
CT = [ 4.7856; 2.4329; 1.8103; 1.2600; 0.6886; 0.4403;]
p = [ 10; 50; 125; 250; 600; 1000;]
saturation_fraction = [1; 0.8; 0.6; 0.5; 0.4; 0;]
w_seaice = [0.0560; 0.02513; 0.02159; 0.01210; 0.00943; 0.00751;]
SA_seaice = [ 5; 4.8; 3.5; 2.5; 1; 0.4;]
t_seaice = [-4.7856; -4.4329; -3.8103; -4.2600; -3.8863; -3.4036;]
[SA_final, CT_final] = ...
gsw_melting_seaice_into_seawater(SA,CT,p,saturation_fraction,w_seaice,SA_seaice,t_seaice)
SA_final =
33.047939199999995
34.135300604999998
34.344962295999999
34.455798880000003
34.418463862000003
34.474563675999995
CT_final =
-0.018758982779967
0.345123135112251
0.020438912479357
0.242677700842234
-0.111076307997557
-0.197363471215418
AUTHOR:
Trevor McDougall & Paul Barker [ help@teos-10.org ]
VERSION NUMBER:
3.04 (3rd December, 2013)
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.
The software is available from http://www.TEOS-10.org