Ocean Current Kinematic Effects on Pitch–Roll Buoy Observations of Mean Wave Direction and Nondirectional Spectra

Abstract

The effects of ocean surface current Doppler frequency shifting on nondirectional spectra and mean wave direction are modeled. The model does not consider physical wave?current interactions. Model values for both ideal surface-following and 10-m-diameter discus hulls are computed. Unusual wave data reported by a 10-m-diameter discus buoy moored in a strong current in the eastern Gulf of Mexico are also analyzed using the model. Results indicate that the unusual characteristics of the measured data can be explained, at least in part, by the observations being made in a frame of reference (the buoy frame) in motion relative to that in which no ocean current would be observed (the frame moving with the current), provided hull response functions are included and reasonable current directions and speeds are assumed.