oce (version 0.9-18)

swSCTp: Salinity from electrical conductivity, temperature and pressure

Description

Compute salinity based on electrical conductivity, temperature, and pressure.

Usage

swSCTp(conductivity, temperature=NULL, pressure=0,
       conductivityUnit=c("ratio", "mS/cm", "S/m"),
       eos=getOption("oceEOS", default="gsw"))

Arguments

conductivity

conductivity ratio, or a CTD object. If a CTD object, then the next 3 arguments are ignored, since the information can be gleaned from the object.

temperature

in-situ temperature [$^\circ$C], defined on the ITS-90 scale; see Temperature units in the documentation for swRho.

pressure

pressure [dbar]

conductivityUnit

string indicating the unit used for conductivity; ratio means actual conductivity divided by standard conductivity (4.2914 S/m).

eos

equation of state, either "unesco" or "gsw".

Value

• Practical salinity.

Details

Calculate salinity from what is actually measured by a CTD, i.e. conductivity, in-situ temperature and pressure. Often this is done by the CTD processing software, but sometimes it is helpful to do this directly, e.g. when there is a concern about mismatches in sensor response times. If eos="unesco" then salinity is calculated using the UNESCO algorithm described by Fofonoff and Millard (1983); if it is "gsw" then the Gibbs-SeaWater formulation is used, via gsw_SP_from_C.

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

See Also

For thermal (as opposed to electrical) conductivity, see swThermalConductivity. For computation of electrical conductivity from salinity, see swCSTp.

Examples

swSCTp(1, T90fromT68(15), 0, eos="unesco") # 35
swSCTp( 1,            15, 0, eos="gsw") # 35