swSigma {oce}R Documentation

Seawater density anomaly

Description

Compute sigma, 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 [degC], 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".

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.

Value

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

Author(s)

Dan Kelley

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

[Package oce version 0.9-18 Index]