swRrho {oce} | R Documentation |
Compute density ratio
swRrho(ctd, sense=c("diffusive", "finger"), smoothingLength=10, df, eos=getOption("oceEOS", default="gsw"))
ctd |
an object of class |
sense |
an indication of the sense of double diffusion under study and therefore of the definition of Rrho; see ‘Details’ |
smoothingLength |
ignored if |
df |
if given, this is provided to |
eos |
equation of state, either |
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_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)
.
Density ratio defined in either the "diffusive"
or
"finger"
sense.
Dan Kelley and Chantelle Layton
library(oce) data(ctd) u <- swRrho(ctd, eos="unesco") g <- swRrho(ctd, eos="gsw") p <- ctd[["p"]] plot(u, p, ylim=rev(range(p)), type='l', xlab=expression(R[rho])) lines(g, p, lty=2, col='red') legend("topright", lty=1:2, legend=c("unesco", "gsw"), col=c("black", "red"))