Montgomery geostrophic streamfunction (75-term equation)



geo_strf_Montgomery = gsw_geo_strf_Montgomery(SA,CT,p,p_ref)


Calculates the Montgomery geostrophic streamfunction (see Eqn. (3.28.1) 
of IOC et al. (2010)).  This is the geostrophic streamfunction for the 
difference between the horizontal velocity at the pressure concerned, p,
and the horizontal velocity on the pressure surface, p_ref.  The 
Montgomery geostrophic streamfunction is the geostrophic streamfunction
for flow in a specifc volume anomaly 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 75-term expression for specific volume of 
Roquet et al. (2015).
Note that p_ref, is the reference pressure to which the streamfunction
is referenced.  When p_ref is zero, "gsw_geo_strf_Montgomery" returns 
the Montgomery geostrophic streamfunction with respect to the sea 
surface, otherwise, the function returns the geostrophic streamfunction
with respect to the (deep) reference pressure p_ref.
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". 
Click for a more detailed description of Montgomery 


SA   =  Absolute Salinity                                       [ g/kg ]
CT   =  Conservative Temperature                               [ deg C ]
p    =  sea pressure                                            [ dbar ]
        ( i.e. absolute pressure - 10.1325 dbar )
p_ref = sea reference pressure                                 [ dbar ]
        ( i.e. absolute reference 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.


geo_strf_Montgomery = Montgomery geostrophic streamfunction  [ m^2/s^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 = 1000
geo_strf_Montgomery = gsw_geo_strf_Montgomery(SA,CT,p,p_ref)
geo_strf_Montgomery =


Trevor McDougall and Paul Barker                     [ ]


3.06.12 (15th June, 2020)


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 section 3.28 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, P.M. Barker, 2015: Accurate
 polynomial expressions for the density and specifc volume of seawater
 using the TEOS-10 standard. Ocean Modelling.
Montgomery, R. B., 1937: A suggested method for representing gradient
 flow in isentropic surfaces.  Bull. Amer. Meteor. Soc. 18, 210-212.
The software is available from