# gsw_specvol_alpha_beta

    specific volume, thermal expansion & saline
    contraction coefficient (75-term equation)

## Contents

- USAGE:
- DESCRIPTION:
- INPUT:
- OUTPUT:
- EXAMPLE:
- AUTHOR:
- VERSION NUMBER:
- REFERENCES:

## USAGE:

    [specvol, alpha, beta] = gsw_specvol_alpha_beta(SA,CT,p)

## DESCRIPTION:

    Calculates specific volume, the appropiate thermal expansion coefficient
    and the appropriate saline contraction coefficient of seawater from
    Absolute Salinity and Conservative Temperature.  This function uses 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                                [ 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:

    specvol =  specific volume                                    [ m^3/kg ]
    alpha  =  thermal expansion coefficient                          [ 1/K ]
              with respect to Conservative Temperature
    beta   =  saline contraction coefficient                        [ kg/g ]
              at constant Conservative Temperature

## EXAMPLE:

    SA = [34.7118; 34.8915; 35.0256; 34.8472; 34.7366; 34.7324;]
    CT = [28.8099; 28.4392; 22.7862; 10.2262;  6.8272;  4.3236;]
    p =  [     10;      50;     125;     250;     600;    1000;]

    [specvol, alpha, beta] = gsw_specvol_alpha_beta(SA,CT,p)

    specvol =

    1.0e-003 *

        0.978626852431313
       0.978222365701325
       0.976155264597929
       0.972961258011157
       0.971026719344908
       0.968989944622149

    alpha =

    1.0e-003 *

       0.324638934509245
       0.322655537959731
       0.281145723210171
       0.173199716344780
       0.146289673594824
       0.129414845334599

    beta =

    1.0e-003 *

       0.717483987596135
       0.717647512290095
       0.726211643644768
       0.750500751749777
       0.755052064788492
       0.757050813384370

## 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 appendix A.20 and appendix K 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, P.M. Barker, 2015: Accurate
     polynomial expressions for the density and specifc volume of seawater
     using the TEOS-10 standard. Ocean Modelling.

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