Measurement of the Statistical Properties of the Ocean Surface with Instrumented Surface Floats. Part I: Theory of Measurement

摘要

Gyro-stabilized vertical accelerometer-roll-pitch-heading floats plus special analog processing and digital recording equipment have been developed to measure roughness properties of the ocean surface associated with gravity wave components up to 1 Hz. A group of interconnecting computer processing routines, some of which incorporate the FFT, have been created to check, transform, and process large amounts of field data. Part I contains a general description of the effort and a detailed account of the informational capabilities of float systems. From dynamical considerations it is shown that the three-dimensional motion of a typical surface particle can be reconstructed from float time series. After a review of the 'linear random model' due to Pierson et al., it is shown how energy flux and effective group velocity of wave components in narrow frequency bands can be computed from float data. Finally, the Longuet-Higgins, Cartwright, Smith method of determining smoothed directional spectra is reviewed. (Author)