Contents
USAGE:
p = gsw_p_from_z(z,lat,{geo_strf_dyn_height},{sea_surface_geopotental})
DESCRIPTION:
Calculates sea pressure from height using computationally-efficient
48-term expression for density, in terms of SA, CT and p (IOC et
al., 2010). Dynamic height anomaly, geo_strf_dyn_height, if provided,
must be computed with its p_ref = 0 (the surface). Also if provided,
sea_surface_geopotental is the geopotential at zero sea pressure. This
function solves Eqn.(3.32.3) of IOC et al. (2010) iteratively for p.
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 IOC et al. (2010). 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:
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 and geo_strf_dyn_height, if provided, must have
dimensions MxN, which are 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:
3.04 (10th December, 2013)
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.
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