Convert From ITS-90 to IPTS-68 Temperature

Today's instruments typically record in the ITS-90 scale, but some old datasets will be in the IPTS-68 scale. T90fromT68() converts from the IPTS-68 to the ITS-90 scale, using Saunders' (1990) formula, while T68fromT90() does the reverse. The difference between IPTS-68 and ITS-90 values is typically a few millidegrees (see ‘Examples’), which is seldom visible on a typical temperature profile, but may be of interest in some precise work. Mostly for historical interest, T90fromT48() is provided to convert from the ITS-48 system to ITS-90.

T68fromT90(temperature)

Arguments

temperature: numeric vector of temperatures]in \(^\circ\)C on the ITS-90 scale.

Value

Corresponding temperatures in \(^\circ\)C on the IPTS-68 scale.

References

P. M. Saunders, 1990. The international temperature scale of 1990, ITS-90. WOCE Newsletter, volume 10, September 1990, page 10. http://www.nodc.noaa.gov/woce/wdiu/wocedocs/newsltr/news10/contents.htm

Other functions that calculate seawater properties: T90fromT48(), T90fromT68(), computableWaterProperties(), locationForGsw(), swAbsoluteSalinity(), swAlpha(), swAlphaOverBeta(), swBeta(), swCSTp(), swConservativeTemperature(), swDepth(), swDynamicHeight(), swLapseRate(), swN2(), swPressure(), swRho(), swRrho(), swSCTp(), swSR(), swSTrho(), swSigma(), swSigma0(), swSigma1(), swSigma2(), swSigma3(), swSigma4(), swSigmaT(), swSigmaTheta(), swSoundAbsorption(), swSoundSpeed(), swSpecificHeat(), swSpice(), swSpiciness0(), swSpiciness1(), swSpiciness2(), swSstar(), swTFreeze(), swTSrho(), swThermalConductivity(), swTheta(), swViscosity(), swZ()

Author

Dan Kelley

Examples

library(oce)
T68 <- seq(3, 20, 1)
T90 <- T90fromT68(T68)
sqrt(mean((T68-T90)^2))
#> [1] 0.003027144