## Contents

## USAGE:

alpha = gsw_alpha(SA,CT,p)

## DESCRIPTION:

Calculates the thermal expansion coefficient of seawater with respect to
Conservative Temperature using the computationally-efficient 75-term
expression for specific volume in terms of SA, CT and p (Roquet et al.,
2015).

Note that the 75-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. (2003). 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:

SA = Absolute Salinity [ g/kg ]
CT = Conservative Temperature (ITS-90) [ deg C ]
p = sea pressure [ dbar ]
(ie. absolute pressure - 10.1325 dbar)

SA & CT need to have the same dimensions.
p may have dimensions 1x1 or Mx1 or 1xN or MxN, where SA & CT are MxN.

## OUTPUT:

alpha = thermal expansion coefficient [ 1/K ]
with respect to Conservative Temperature

## EXAMPLE:

SA = [34.7118; 34.8915; 35.0256; 34.8472; 34.7366; 34.7324;]
CT = [28.7856; 28.4329; 22.8103; 10.2600; 6.8863; 4.4036;]
p = [ 10; 50; 125; 250; 600; 1000;]

alpha = gsw_alpha(SA,CT,p)

alpha =

1.0e-003 *

0.324464211877393
0.322610094680523
0.281335030247435
0.173529986885424
0.146898108553385
0.130265123640082

## AUTHOR:

Paul Barker and Trevor McDougall [ 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.
See Eqn. (2.18.3) of this TEOS-10 manual.

McDougall, T.J., D.R. Jackett, D.G. Wright and R. Feistel, 2003:
Accurate and computationally efficient algorithms for potential
temperature and density of seawater. J. Atmosph. Ocean. Tech., 20,
pp. 730-741.

Roquet, F., G. Madec, T.J. McDougall and P.M. Barker, 2015: Accurate
polynomial expressions for the density and specific volume of seawater
using the TEOS-10 standard. *Ocean Modelling*, **90**, pp. 29-43.
http://dx.doi.org/10.1016/j.ocemod.2015.04.002

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