NBDO Large Discus and NOMAD Buoy Calibrations with WRANSAC

The hull power transfer functions of two operational NOAA Data Buoy Office (NDBO) buoys have been established by use of the Waverider Analyzer Satellite Communicator (WRANSAC). In March 1978, the WRANSAC was tethered to an NDBO 12-meter diameter discus buoy located at site 42002 ( N, W) in the Gulf of Mexico. Comparison data from 43 hourly reports were used to generate the first hull power transfer function based on at-sea measurements. In April 1978, the WRANSAC was tethered to a NOMAD buoy at site 42003 ( N, W) in the Gulf of Mexico for 6 weeks. The first few weeks of data at this second site were sufficient to determine a reliable hull power transfer function; subsequent comparison data were used to assess the accuracy of the calibrated wave measurement system on board the NOMAD, using the WRANSAC as a reference. A description of the procedure used to compute the hull transfer function for the 12-meter discus buoy and the NOMAD buoy is presented herein, with an analysis of the wave data accuracy provided by these buoys.