In analogy with historic analyses of shallow-water tide-gauge records, in which tides and theirhigher harmonics are modified by sea level changes induced by atmospheric disturbances, it is shown thatdeep-sea currents can be interpreted as motions at predominantly inertial-tidal harmonic frequencies modifiedby slowly varying background conditions. In this interpretation, their kinetic energy spectra may not besmoothed into a quasi-stochastic continuum for (random-)statistic confidence. Instead, they are consideredas quasi-deterministic line-spectra. Thus, the climatology of the internal wave field and its slowly varyingbackground can be inferred from line spectra filling the cusps around nonlinear tidal-inertial harmonics, assuggested previously. |
