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. (2013).
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. (2013). 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:
3.02 (17th November, 2012)
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, 2013: 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 J. Atm. Ocean. Technol., xx, yyy-zzz.
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
