# gsw_geo_strf_dyn_height

    dynamic height anomaly

## Contents

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

## USAGE:

    [geo_strf_dyn_height, in_funnel] = gsw_geo_strf_dyn_height(SA,CT,p,delta_p,interp_style)

## DESCRIPTION:

    Calculates dynamic height anomaly as the integral of specific volume
    anomaly from the the sea surface pressure (0 Pa) to the pressure p.
    Hence, geo_strf_dyn_height is the dynamic height anomaly with respect to
    the sea surface.  This is the geostrophic streamfunction for the
    difference between the horizontal velocity at the pressure concerned, p,
    and the horizontal velocity at the sea surface.  Dynamic height anomaly
    is the geostrophic streamfunction in an isobaric surface.  The reference
    values used for the specific volume anomaly are SA = SSO = 35.16504 g/kg
    and CT = 0 deg C.  This function calculates specific volume anomaly
    using the computationally efficient 25-term expression for specific
    volume of McDougall et al. (2010).
    Under the default setting, this function evaluates the pressure integral
    of specific volume using SA and CT “interploted” with respect to pressure
    using a scheme based on the method of Reiniger and Ross (1968).  Our
    method uses a weighted mean of (i) values obtained from linear
    interpolation of the two nearest data points, and (ii) a linear
    extrapolation of the pairs of data above and below. This "curve fitting"
    method resembles the use of cubic splines.  If the option “linear” is
    chosen, the function interpolates Absolute Salinity and Conservative
    Temperature linearly with presure in the vertical between “bottles”.

    Click for a more detailed description of dynamic
    height anomaly.

## 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 Mx1 or 1xN or MxN, where SA & CT are MxN.

    OPTIONAL:
    delta_p      = maximum interpolation distance between bottles.
    interp_style = interpolation technique.
                 = if nothing is entered the programme defaults to "curved"
                   interpolation between bottles in the vertical.
                 = if "linear" or "lin" is entered then the programme
                   interpolates linearly between bottles in the
                   vertical.

## OUTPUT:

    geo_strf_dyn_height = dynamic height anomaly                 [ m^2/s^2 ]

    in_funnel          =  0, if SA, CT and p are outside the "funnel"
                       =  1, if SA, CT and p are inside the "funnel"
    Note. The term "funnel" describes the range of SA, CT and p over which
      the error in the fit of the computationally-efficient 25-term
      expression for density was calculated (McDougall et al., 2010).

## EXAMPLE 1:

    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;]

    [geo_strf_dyn_height, in_funnel] = ...
              gsw_geo_strf_dyn_height(SA,CT,p)

    Note that the following which will porduce the same result.

    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;]
    delta_p = 1;

    [geo_strf_dyn_height, in_funnel] = ...
             gsw_geo_strf_dyn_height(SA,CT,p,delta_p)

      geo_strf_dyn_height =          in_funnel =

             0                         1
       -2.9016                         1
       -6.6640                         1
       -9.9753                         1
      -14.2648                         1
      -17.8694                         1

## EXAMPLE 2:

    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;]
    delta_p = 1;

    [geo_strf_dyn_height, in_funnel] = ...
             gsw_geo_strf_dyn_height(SA,CT,p,delta_p,'linear')

      geo_strf_dyn_height =          in_funnel =

             0                         1
       -2.9016 						1
       -6.5949 						1
       -9.9062 						1
      -14.1957 						1
      -17.8003 						1

## AUTHOR:

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

## VERSION NUMBER:

    2.0, 25th August, 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 Eqn. (3.7.3) and section 3.27 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.

    Reiniger, R. F. and C. K. Ross, 1968: A method of interpolation with
     application to oceanographic data. Deep-Sea Res. 15, 185-193.

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