gsw_p_from_z

pressure from height (48-term equation)

Contents

USAGE:

p = gsw_p_from_z(z,lat,{geo_strf_dyn_height})

DESCRIPTION:

Calculates sea pressure from height using computationally-efficient 
48-term expression for density, in terms of SA, CT and p (McDougall et
al., 2011).  Dynamic height anomaly, geo_strf_dyn_height, if provided,
must be computed with its p_ref = 0 (the surface).

Note. Height (z) is NEGATIVE in the ocean.  Depth is -z.  
      Depth is not used in the GSW computer software library. 

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).  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".
TEOS-10 
Click for a more detailed description of calculating
pressure from height.

INPUT:

z   =  height                                                      [ m ]
 Note. At sea level z = 0, and since z (HEIGHT) is defined
   to be positive upwards, it follows that while z is
   positive in the atmosphere, it is NEGATIVE in the ocean.
lat =  latitude in decimal degrees north                 [ -90 ... +90 ]
OPTIONAL:
geo_strf_dyn_height = dynamic height anomaly                 [ m^2/s^2 ]
  Note that the reference pressure, p_ref, of geo_strf_dyn_height must
   be zero (0) dbar.
lat may have dimensions 1x1 or Mx1 or 1xN or MxN, where z is MxN.
geo_strf_dyn_height, if provided, must have dimensions MxN, which is
the same as z.

OUTPUT:

 p  =  sea pressure                                             [ dbar ]
       ( i.e. absolute pressure - 10.1325 dbar )

EXAMPLE:

z   =  [     10;      50;     125;     250;     600;    1000;]
lat = 4;
p = gsw_p_from_z(z,lat)
p =
 1.0e+003 *
  -0.010055235976847
  -0.050271267635044
  -0.125655128514602
  -0.251233371685054
  -0.602442093622451
  -1.003079508920876

AUTHOR:

Trevor McDougall, Claire Roberts-Thomson and Paul Barker.
                                                [ help@teos-10.org ]

VERSION NUMBER:

3.01 (26th 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.
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.
Saunders, P. M., 1981: Practical conversion of pressure to depth.
 Journal of Physical Oceanography, 11, 573-574.
Moritz (2000) Goedetic reference system 1980. J. Geodesy, 74, 128-133.
This software is available from http://www.TEOS-10.org