HiWinGS Buoy Measurements of Wave Statistics and Energy Spectra

From October 9th to November 13th 2013, the High Wind Gas Exchange Study (HiWinGS) research cruise took place on board the R/V Knorr in the Labrador Sea, with the aim of gaining a greater understanding of the dependence of air-sea fluxes on sea state under high wind conditions. Fluxes of momentum, heat, moisture, sea-spray aerosol and several trace gases including CO2, DMS, and methanol were determined using the eddy covariance technique. Spar buoys, designed and built at the UK National Oceanography Centre, and a Datawell DWR-G4 Directional Waverider buoy were deployed to measure wave spectra and wave breaking.

A wide variety of wind speeds and sea states were observed: 10-minute averaged Hs values during HiWinGS were between 1.38 and 11.4 m, and a 10-minute average U10 of greater than 15 m/s was observed for a total of 165 hours during the campaign.

Here we present a comparison between the wave measurements from the different buoys. We determine the capabilities of the buoys at measuring sea state in a variety of conditions and examine the reliability and accuracy of wind-sea/swell separations calculated from the 1-D spectra produced by the buoys. The spar buoys are found to represent the wave field, particularly local wind-sea, and separate wind-sea/swell energies more accurately than the waverider buoy.