Compute density ratio
an oce object that holds salinity
, temperature
, and
pressure
. If eos
is "gsw"
, then it must also hold longitude
and
latitude
.
an indication of the sense of double diffusion under study and therefore of the definition of Rrho; see “Details”
ignored if df
supplied, but otherwise the
latter is calculated as the number of data points, divided by the number
within a depth interval of smoothingLength
metres.
if given, this is provided to smooth.spline()
.
equation of state, either "unesco"
or "gsw"
.
Density ratio defined in either the "diffusive"
or
"finger"
sense.
This computes Rrho (density ratio) from a ctd
object.
If eos="unesco"
, this is done by calculating salinity and
potential-temperature derivatives from smoothing splines whose properties
are governed by smoothingLength
or df
. If
sense="diffusive"
the definition is
\((beta*dS/dz)/(alpha*d(theta)/dz)\) and
the reciprocal for "finger"
.
If eos="gsw"
, this is done by extracting absolute salinity and
conservative temperature, smoothing with a smoothing spline as in the
"unesco"
case, and then calling gsw::gsw_Turner_Rsubrho()
on these smoothed fields. Since the gsw function works on mid-point
pressures, approx()
is used to interpolate back to the original
pressures.
If the default arguments are acceptable, ctd[["Rrho"]]
may be used
instead of swRrho(ctd)
.
Other functions that calculate seawater properties:
T68fromT90()
,
T90fromT48()
,
T90fromT68()
,
computableWaterProperties()
,
locationForGsw()
,
swAbsoluteSalinity()
,
swAlphaOverBeta()
,
swAlpha()
,
swBeta()
,
swCSTp()
,
swConservativeTemperature()
,
swDepth()
,
swDynamicHeight()
,
swLapseRate()
,
swN2()
,
swPressure()
,
swRho()
,
swSCTp()
,
swSR()
,
swSTrho()
,
swSigma0()
,
swSigma1()
,
swSigma2()
,
swSigma3()
,
swSigma4()
,
swSigmaTheta()
,
swSigmaT()
,
swSigma()
,
swSoundAbsorption()
,
swSoundSpeed()
,
swSpecificHeat()
,
swSpice()
,
swSstar()
,
swTFreeze()
,
swTSrho()
,
swThermalConductivity()
,
swTheta()
,
swViscosity()
,
swZ()