gsw_geo_strf_dyn_height

dynamic height anomaly

Contents

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”.
TEOS-10
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