oce (version 0.9-18)

swSigma: Seawater density anomaly

Description

Compute $\sigma_\theta$, the density of seawater, minus 1000 kg/m$^3$.

Usage

swSigma(salinity, temperature=NULL, pressure=NULL, longitude=300,
  latitude=30, eos=getOption("oceEOS", default="gsw"))

Arguments

salinity

either practial salinity or an oce object; see Details.

temperature

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

pressure

pressure [dbar].

longitude

longitude of observation (only used if eos="gsw").

latitude

latitude of observation (only used if eos="gsw").

eos

name of equation of state to be used, either "unesco" or "gsw".

Value

• Density anomaly [kg/m$^3$], defined as swRho - 1000 kg/m$^3$.

Details

If the first argument is an oce object, then salinity, etc., are extracted from it, and used for the calculation instead of any values provided in the other arguments.

References

See citations provided in the swRho documentation.

See Also

Related density routines include: swRho, swSigmaT, swSigmaTheta, swSigma0, etc.

Examples

library(oce)
swSigma(35, 13, 1000, eos="gsw")                   # 30.82397
swSigma(35, T90fromT68(13), 1000, eos="unesco")    # 30.8183