The Comparison of Discus Buoy Wave Spectra Produced by Buoy-Fixed and Vertically Stabilized Accelerometers

A 12-meter discus buoy was instrumented to measure wave spectra by the NOAA Data Buoy Office (NDBO) with both buoy-fixed and vertically stabilized accelerometers feeding a data acquisition system which, on a 3-hour cycle, acquired and stored a 15-minute time series of the two sensor outputs. The buoy was deployed and operated in the Atlantic Ocean for several months, and produced wave data over a range of conditions. This paper describes the sensors and data acquisition system. The data are compared on the basis of their acceleration spectra; phase and coherence functions for the two time series are also examined. Results are presented which indicate that, for frequencies where significant wave energy is measured by the buoy, the output of the buoy-fixed accelerometer can be used to replace that of the vertically stabilized accelerometer.