# gsw_rho_alpha_beta_CT25

    in-situ density, thermal expansion & saline
    contraction coefficient from CT

## Contents

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

## USAGE:

    [rho, alpha_wrt_CT, beta_const_CT] = gsw_rho_alpha_beta_CT(SA,CT,p)

## DESCRIPTION:

    Calculates in-situ density, the appropiate thermal expansion coefficient
    and the appropriate saline contraction coefficient of seawater from
    Absolute Salinity and Conservative Temperature.

    Note that this function uses the full Gibbs function.  There is an
    alternative to calling this function, namely
    gsw_rho_alpha_beta_CT25(SA,CT,p), which uses the computationally
    efficient 25-term expression for density in terms of SA, CT and p
    (McDougall et al., (2010)).  For SA, CT and p values which fall inside
    the oceanographic "funnel" (McDougall et al., 2010), this
    computationally efficient (i.e. faster) 25-term version fits the
    underlying laboratory density data almost as well as does the density
    derived from the full TEOS-10 Gibbs function.

    Click for a more detailed description of density.
    Click for a more detailed description of the
    thermal expansion coefficient with respect to
    Conservative Temperature (alpha_wrt_CT).
    Click for a more detailed description of the
    saline contraction coefficient at constant
    Conservative Temperature (beta_const_CT).

## 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:

    rho            =  in-situ density                            [ kg m^-3 ]
    alpha_wrt_CT   =  thermal expansion coefficient                  [ 1/K ]
                      with respect to Conservative Temperature
    beta_const_CT  =  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;]

    [rho, alpha_wrt_CT, beta_const_CT] = gsw_rho_alpha_beta_CT(SA,CT,p)

    rho =

     1.0e+003 *

      1.021840179764021
      1.022262699103554
      1.024427709285783
      1.027790199901620
      1.029837716779620
      1.032002400877215

    alpha_wrt_CT =

     1.0e-003 *

      0.324707799687110
      0.322723974596565
      0.281179083137791
      0.173138326981408
      0.146269069937061
      0.129427106726016

    beta_const_CT =

     1.0e-003 *

      0.717486805409467
      0.717647610706394
      0.726219007035780
      0.750509225553259
      0.755062996958255
      0.757065832066916

## AUTHOR:

    Trevor McDougall and Paul Barker           [ help_gsw@csiro.au ]

## VERSION NUMBER:

    2.0 (30th September, 2010)

## 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 (2.8), (2.18) and (2.19) of this TEOS-10 Manual.

    McDougall T. J., D. R. Jackett, P. M. Barker, C. Roberts-Thomson, R.
     Feistel and R. W. Hallberg, 2010:  A computationally efficient 25-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