Motion Correction for Shipborne Turbulence Sensors

Abstract

A method for removing ship motion from wind measurements using a simple and inexpensive strap-down system of accelerometers is described and analyzed. In slight seas, error analysis indicates that mean root-mean-square uncertainties associated with the motion correction are 0.03 and 0.006 m s?1 for the horizontal and vertical wind, respectively, for all runs analyzed. The mean uncertainty in the wind stress due to motion correction is 8 ? 10?4 N m?2. In a shallow coastal sea setting, ship motion appears to almost always be successfully detected and removed from the vertical component of the observed wind. The horizontal wind components appear to be successfully corrected in 86% of the runs analyzed. Motion correction is shown to have a significant influence on the covariance-calculated wind stress. In approximately half of the runs analyzed the wind stress changes by more than 15%. Motion correction has a smaller effect on the heat fluxes.