Compute height above the surface. This is the negative of depth,
and so is defined simply in terms of swDepth.
swZ(pressure, latitude = 45, eos = getOption("oceEOS", default =
  "gsw"))either pressure [dbar], in which case lat must also
be given, or a ctd object, in which case lat will be inferred
from the object.
Latitude in \(^\circ\)N or radians north of the equator.
indication of formulation to be used, either "unesco" or
"gsw".
Other functions that calculate seawater properties: T68fromT90,
  T90fromT48, T90fromT68,
  swAbsoluteSalinity,
  swAlphaOverBeta, swAlpha,
  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