Compute electrical conductivity ratio based on salinity, temperature, and pressure (relative to the conductivity of seawater with salinity=35, temperature68=15, and pressure=0).
Usage
swCSTp(
salinity,
temperature = 15,
pressure = 0,
eos = getOption("oceEOS", default = "gsw")
)Arguments
- salinity
practical salinity, or a CTD object (in which case its temperature and pressure are used, and the next two arguments are ignored)
- temperature
in-situ temperature (\(^\circ\)C), defined on the ITS-90 scale; see the examples, as well as the “Temperature units” section in the documentation for
swRho().- pressure
pressure (dbar)
- eos
equation of state, either
"unesco"or"gsw".
Value
Conductivity ratio (unitless), i.e. the ratio of conductivity to the conductivity at salinity=35, temperature=15 (IPTS-68 scale) and pressure=0, which has numerical value 42.9140 mS/cm = 4.29140 S/m (see Culkin and Smith, 1980, in the regression result cited at the bottom of the left-hand column on page 23).
Details
If eos="unesco", the calculation is done by a bisection root search
on the UNESCO formula relating salinity to conductivity, temperature, and
pressure (see swSCTp()). If it is "gsw" then the
Gibbs-SeaWater formulation is used, via gsw::gsw_C_from_SP().
References
Fofonoff, P. and R. C. Millard Jr, 1983. Algorithms for computation of fundamental properties of seawater. Unesco Technical Papers in Marine Science, 44, 53 pp.
Culkin, F., and Norman D. Smith, 1980. Determination of the concentration of potassium chloride solution having the same electrical conductivity, at 15 C and infinite frequency, as standard seawater of salinity 35.0000 ppt (Chlorinity 19.37394 ppt). IEEE Journal of Oceanic Engineering, 5, pp 22-23.
See also
For thermal (as opposed to electrical) conductivity, see
swThermalConductivity(). For computation of salinity from
electrical conductivity, see swSCTp().
Other functions that calculate seawater properties:
T68fromT90(),
T90fromT48(),
T90fromT68(),
computableWaterProperties(),
locationForGsw(),
swAbsoluteSalinity(),
swAlpha(),
swAlphaOverBeta(),
swBeta(),
swConservativeTemperature(),
swDepth(),
swDynamicHeight(),
swLapseRate(),
swN2(),
swPressure(),
swRho(),
swRrho(),
swSCTp(),
swSR(),
swSTrho(),
swSigma(),
swSigma0(),
swSigma1(),
swSigma2(),
swSigma3(),
swSigma4(),
swSigmaT(),
swSigmaTheta(),
swSoundAbsorption(),
swSoundSpeed(),
swSpecificHeat(),
swSpice(),
swSpiciness0(),
swSpiciness1(),
swSpiciness2(),
swSstar(),
swTFreeze(),
swTSrho(),
swThermalConductivity(),
swTheta(),
swViscosity(),
swZ()
Examples
stopifnot(abs(1.0 - swCSTp(35, T90fromT68(15), 0, eos = "unesco")) < 1e-7)
stopifnot(abs(1.0 - swCSTp(34.25045, T90fromT68(15), 2000, eos = "unesco")) < 1e-7)
stopifnot(abs(1.0 - swCSTp(34.25045, T90fromT68(15), 2000, eos = "gsw")) < 1e-7)