Compute \(\alpha\), the thermal expansion coefficient for seawater.
swAlpha(salinity, temperature = NULL, pressure = 0, longitude = NULL,
latitude = NULL, eos = getOption("oceEOS", default = "gsw"))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).
in-situ temperature [\(^\circ\)C], defined
on the ITS-90 scale; see “Temperature units” in the documentation for
swRho.
pressure [dbar]
longitude of observation (only used if eos="gsw";
see ‘Details’).
latitude of observation (only used if eos="gsw"; see
‘Details’).
equation of state, either "unesco" or "gsw".
Value in 1/degC.
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.
Other functions that calculate seawater properties: T68fromT90,
T90fromT48, T90fromT68,
swAbsoluteSalinity,
swAlphaOverBeta, swBeta,
swCSTp,
swConservativeTemperature,
swDepth, swDynamicHeight,
swLapseRate, swN2,
swPressure, swRho,
swRrho, swSCTp,
swSTrho, swSigma0,
swSigma1, swSigma2,
swSigma3, swSigma4,
swSigmaTheta, swSigmaT,
swSigma, swSoundAbsorption,
swSoundSpeed, swSpecificHeat,
swSpice, swTFreeze,
swTSrho,
swThermalConductivity,
swTheta, swViscosity,
swZ