either salinity [PSU] (in which case
temperature and pressure must be provided) or
a ctd object (in which case salinity,
temperature and pressure ar
temperature
in-situ temperature [$^\circ$C]
pressure
seawater pressure [dbar]
Value
Spice [kg/m$^3$].
Details
If the first argument is a ctd object, then salinity,
temperature and pressure values are extracted from it, and used for
the calculation.
Roughly speaking, seawater with a high spiciness is relatively warm
and salty compared with less spicy water. Another interpretation is
that spice is a variable measuring distance orthogonal to isopycnal
lines on TS diagrams (if the diagrams are scaled to make the
isopycnals run at 45 degres). The definition used here is that of
Pierre Flament. (Other formulations exist.) Note that pressure is
ignored in the definition. Spiceness is sometimes denoted
$\pi(S,t,p)$.
References
P. Flament, 2002.
A state variable for characterizing water masses and their diffusive
stability: spiciness. Progr. Oceanog.,
54, 493-501.