Contents
USAGE:
geo_strf_dyn_height = gsw_geo_strf_dyn_height(SA,CT,p,p_ref)
DESCRIPTION:
Calculates dynamic height anomaly as the integral of specific volume
anomaly from the pressure p of the "bottle" to the reference pressure
p_ref.
Hence, geo_strf_dyn_height is the dynamic height anomaly with respect
to a given reference pressure. This is the geostrophic streamfunction
for the difference between the horizontal velocity at the pressure
concerned, p, and the horizontal velocity at p_ref. Dynamic height
anomaly is the geostrophic streamfunction in an isobaric surface. The
reference values used for the specific volume anomaly are
SSO = 35.16504 g/kg and CT = 0 deg C. This function calculates
specific volume anomaly using the computationally efficient 48-term
expression for specific volume of McDougall et al. (2011).
This function evaluates the pressure integral of specific volume using
SA and CT "interpolated" 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.
Note that the 48-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. (2011). For dynamical oceanography we may
take the 48-term rational function expression for density as essentially
reflecting the full accuracy of TEOS-10. 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 ]
( i.e. absolute pressure - 10.1325 dbar )
p_ref = reference pressure [ dbar ]
( i.e. reference 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.
p_ref needs to be a single value, it can have dimensions 1x1 or Mx1 or
1xN or MxN.
OUTPUT:
geo_strf_dyn_height = dynamic height anomaly [ m^2/s^2 ]
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;]
p_ref = 1000
geo_strf_dyn_height = gsw_geo_strf_dyn_height(SA,CT,p,p_ref)
geo_strf_dyn_height =
17.292238085013480
14.933132053101872
11.187848272884139
7.901116636076495
3.607208810117299
0
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;]
p_ref = 500
geo_strf_dyn_height = gsw_geo_strf_dyn_height(SA,CT,p,p_ref)
geo_strf_dyn_height =
12.591685524603520
10.232579492691912
6.487295712474179
3.200564075666534
-1.093343750292661
-4.700552560409960
AUTHOR:
Paul Barker, Jeff Dunn and Trevor McDougall [ help@teos-10.org ]
VERSION NUMBER:
3.01 (18th May, 2011)
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., P.M. Barker, R. Feistel and D.R. Jackett, 2011: A
computationally efficient 48-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
