Contents
USAGE:
[CT, CT_multiple] = gsw_CT_from_rho(rho,SA,p)
DESCRIPTION:
Calculates the Conservative Temperature of a seawater sample, for given
values of its density, Absolute Salinity and sea pressure (in dbar) using
the computationally-efficient 48-term expression for density in terms
of SA, CT and p (McDougall et al., 2011).
Note that the 48-term equation has been fitted in a restricted range of
parameter space, and is most accurate inside the "oceanographic funnel"
described in McDougall et al. (2011). The GSW library function
"gsw_infunnel(SA,CT,p)" is avaialble to be used if one wants to test if
some of one's data lies outside this "funnel".
INPUT:
rho = density of a seawater sample (e.g. 1026 kg/m^3) [ kg/m^3 ]
Note. This input has not had 1000 kg/m^3 subtracted from it.
That is, it is 'density', not 'density anomaly'.
SA = Absolute Salinity [ g/kg ]
p = sea pressure [ dbar ]
( i.e. absolute pressure - 10.1325 dbar )
rho & SA need to have the same dimensions.
p may have dimensions 1x1 or Mx1 or 1xN or MxN, where rho & SA are MxN.
OUTPUT:
CT = Conservative Temperature (ITS-90) [ deg C ]
CT_multiple = Conservative Temperature (ITS-90) [ deg C ]
Note that at low salinities, in brackish water, there are two
possible temperatures for a single density. This programme will
output both valid solutions. To see this second solution the user
must call the programme with two outputs (i.e. [CT, CT_multiple]),
if there is only one possible solution and the programme has been
called with twooutputs the second variable will be set to NaN.
EXAMPLE:
rho = [1021.8484; 1022.2647; 1024.4207; 1027.7841; 1029.8287; 1031.9916;]
SA = [ 34.7118; 34.8915; 35.0256; 34.8472; 34.7366; 34.7324;]
p = [ 10; 50; 125; 250; 600; 1000;]
[CT, CT_multiple] = gsw_CT_from_rho(rho,SA,p)
CT =
28.785919240184850
28.434000931649784
22.810740149969192
10.262124247240154
6.887196810485858
4.401886081747603
CT_multiple =
NaN
NaN
NaN
NaN
NaN
NaN
AUTHOR:
Trevor McDougall & Paul Barker [ help@teos-10.org ]
VERSION NUMBER:
3.01 (26th May, 2011)
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 sections 3.1 and 3.3 of this TEOS-10 Manual.
McDougall T.J., P.M. Barker, R. Feistel and D.R. Jackett, 2011: A
computationally efficient 48-term expression for the density of
seawater in terms of Conservative Temperature, and related properties
of seawater. To be submitted to Ocean Science Discussions.
The software is available from http://www.TEOS-10.org