Sea water freezing temperature calculator

SEAWATER_FREEZETEMP approximates the freezing temperature (°C) of
sea water.

NOT VALID FOR FRESH WATER! This model is only valid for 4 < S_ppt < 40.

INPUTS: (can be arrays)
S_psu = salinity of water in practical salinity units (close to ppt).
P_Pa = hydrostatic pressure in pascals.
Valid pressure range is up to 500000 Pa or 500 kPa or ~ 50 atm within
0.00°C. However, for 27 < S < 35 psu, the model may be adequate for
pressures above this range.

OUTPUT:
T_f = freezing temperature in degrees celsius.

EXAMPLE:
seawater_freezetemp(40,bar2Pa(50))

ans =

-2.5886

Model from page 29 of UNESCO Algorithms for computation of fundamental
properties of seawater. UNESCO Technical Papers in Marine Science, 1983, adapted from work by Millero and Leung, 1976.

Thanks to Val Schmidt for pointing out the much more comprehensive, well-documented, free set of functions found here: http://www.teos-10.org/software.htm.

The example above uses the unit conversion functions acknowledged below.