An example of a wave-height series is given, in which part of the observed variation seems to be induced by the mooring. It is argued that unexpected semi-tidal modulations in measured wave-height can be an indication of a mooring that is too rigid. By truncating observed wave spectra from a deep-water location, it is demonstrated how the high-frequency cut-off limit of a wave measurement influences the most commonly used wave parameters. It is observed that the accuracy of common wave parameters remains acceptable up to a cut-off limit in the range of 0.30–0.35 Hz if the spectra above the cut-off frequency are replaced by a prognostic f−5 tail. Finally it is noted that the procedure of connecting time stamps to wave measurements can in some cases introduce an artificial time-lag compared to the real-time sea state. 相似文献