swBeta(salinity, temperature=NULL, pressure=0,
longitude=300, latitude=30, eos=getOption("oceEOS", default="gsw"))temperature and
pressure must be provided) or an oce object (in which
case salinity, etc. are inferred from the object).swRho.eos="gsw"; see
eos="gsw"; see
"unesco" or "gsw".ctd object, then salinity,
temperature and pressure values are extracted from it, and used for the
calculation.eos="unesco" formulae are based on the UNESCO equation of
state, but are formulaed empirically by Trevor J. McDougall, 1987, Neutral
Surfaces, Journal of Physical Oceanography, volume 17, pages 1950-1964. The
eos="gsw" formulae come from GSW; see references in the
swRho documentation.