Performance of moored GPS wave buoys

Abstract

ABSTRACT Small, lightweight, and easy-to-deploy Global Positioning Satellite (GPS)-based miniature wave buoys (mini-buoys) are increasing in popularity. Most are deployed as Lagrangian drifters, so their utility for engineering applications, requiring a nearshore mooring, has remained in question. We evaluated the performance of five moored mini-buoys off the coast of Duck, North Carolina at Field Research Facility (FRF). We collected 8 months of data over two deployments; first near the FRF’s 8-m array and then near a Datawell Waverider in 17-m depth. We deployed an Acoustic Doppler Current Profiler (ADCP) that measured waves and currents, and compared it to the nearby operational system as a performance benchmark for the mini-buoys. The mini-buoys performed well, with statistics similar to the benchmark for wave frequency spectra and spectral parameters, and they outperformed the benchmark on directional parameters. However, mini-buoy communication was sometimes interrupted by tilting or submersion, which manifested as low-frequency noise or drop-outs. If a mooring was taut, forced by winds or currents and exacerbated by tangled lines or shallower depths, then mini-buoys were more susceptible to communication issues. Overall, these issues were rare; thus, mini-buoys were found to be appropriate for many applications.