either salinity (in which case pressure, etc. must
be provided) or a ctd object (in which case
salinity, etc. are determined from the object, and must not be
provided in the argum
pressure
pressure in dbar.
longitude
longitude of observation.
latitude
latitude of observation.
Value
Absolute salinity in $g/kg$.
Details
If the first argument is a ctd object, then values of salinity,
etc, are extracted from it, and used for the calculation.
The absolute salinity is calculated using the TEOS-10 function
gsw_sa_from_sp. Typically, this is a fraction of a unit higher than
practical salinity as defined in the UNESCO formulae from the 1980s.
References
[1] McDougall, T.J. and P.M. Barker, 2011: Getting started with
TEOS-10 and the Gibbs Seawater (GSW) Oceanographic Toolbox, 28pp.,
SCOR/IAPSO WG127, ISBN 978-0-646-55621-5.
[2] The TEOS-10 library is provided at www.teos-10.org.
[3] A programming interface to the matlab version of the TEOS library is
provided at http://www.teos-10.org/pubs/gsw/html/gsw_contents.html.
See Also
The related TEOS-10 quantity ``conservative temperature'' may be
computed with swConservativeTemperature. For a ctd object,
absolute salinity may also be recovered by indexing as e.g.
ctd[["absoluteSalinity"]] or ctd[["SA"]].