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 75-term
expression for specific volume (Roquet et al., 2015).
This function evaluates the pressure integral of specific volume using
SA and CT interpolated using the MRST-PCHIP method of Barker and
McDougall (2020). This "curve fitting" method uses a Piecewise Cubic
Hermite Interpolating Polynomial to produce a smooth curve with minimal
artificial watermasses between the observed data points.
Note that the 75-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. (2003). 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 =
16.829126675036644
14.454693755102685
10.727894578402342
7.699845274649316
3.578081589449148
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 =
12.172172845782585
9.797739925848624
6.070940749148281
3.042891445395256
-1.078872239804912
-4.656953829254061
AUTHOR:
Paul Barker and Trevor McDougall [ help@teos-10.org ]
VERSION NUMBER:
3.06.12 (29th July, 2021)
REFERENCES:
Barker, P.M., and T.J. McDougall, 2020: Two interpolation methods using
multiply-rotated piecewise cubic hermite interpolating polynomials.
J. Atmosph. Ocean. Tech., 37, pp. 605-619.
http://dx.doi.org/10.1175/JTECH-D-19-0211.1
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, D.G. Wright and R. Feistel, 2003:
Accurate and computationally efficient algorithms for potential
temperature and density of seawater. J. Atmosph. Ocean. Tech., 20,
pp. 730-741.
Roquet, F., G. Madec, T.J. McDougall and P.M. Barker, 2015: Accurate
polynomial expressions for the density and specific volume of seawater
using the TEOS-10 standard. Ocean Modelling, 90, pp. 29-43.
http://dx.doi.org/10.1016/j.ocemod.2015.04.002
The software is available from http://www.TEOS-10.org
