R: Seawater thermal expansion coefficient

swAlpha {oce} | R Documentation

## Seawater thermal expansion coefficient

### Description

Compute alpha, the thermal expansion coefficient for seawater.

### Usage

    swAlpha(
      salinity,
      temperature = NULL,
      pressure = 0,
      longitude = NULL,
      latitude = NULL,
      eos = getOption("oceEOS", default = "gsw")
    )

### Arguments

`salinity` | either practical salinity (in which case `temperature` and `pressure` must be provided) or an `oce` object (in which case `salinity`, etc. are inferred from the object).
`temperature` | in-situ temperature (degC), defined on the ITS-90 scale; see “Temperature units” in the documentation for `swRho()`.
`pressure` | pressure (dbar)
`longitude` | longitude of observation (only used if `eos="gsw"`; see ‘Details’).
`latitude` | latitude of observation (only used if `eos="gsw"`; see ‘Details’).
`eos` | equation of state, either `"unesco"` or `"gsw"`.

### Value

Value in 1/degC.

### Author(s)

Dan Kelley

### References

The `eos="unesco"` formulae are based on the UNESCO equation of state, but are formulated empirically by Trevor J. McDougall, 1987, Neutral Surfaces, Journal of Physical Oceanography, volume 17, pages 1950-1964. The `eos="gsw"` formulae come from GSW; see references in the `swRho()` documentation.

### See Also

Other functions that calculate seawater properties: `T68fromT90()`, `T90fromT48()`, `T90fromT68()`, `computableWaterProperties()`, `locationForGsw()`, `swAbsoluteSalinity()`, `swAlphaOverBeta()`, `swBeta()`, `swCSTp()`, `swConservativeTemperature()`, `swDepth()`, `swDynamicHeight()`, `swLapseRate()`, `swN2()`, `swPressure()`, `swRho()`, `swRrho()`, `swSCTp()`, `swSR()`, `swSTrho()`, `swSigma0()`, `swSigma1()`, `swSigma2()`, `swSigma3()`, `swSigma4()`, `swSigmaTheta()`, `swSigmaT()`, `swSigma()`, `swSoundAbsorption()`, `swSoundSpeed()`, `swSpecificHeat()`, `swSpice()`, `swSstar()`, `swTFreeze()`, `swTSrho()`, `swThermalConductivity()`, `swTheta()`, `swViscosity()`, `swZ()`

[Package oce version 1.7-2 Index]