Directional wave measurements from the ASIS (Air-Sea Interaction Spar) buoy

During the spring of 1997 the Air Sea Interaction Spar (ASIS) buoy was deployed in the northeastern Gulf of Mexico to study meteorological forcing and ocean wave dynamics. This buoy is specially designed to produce little surface disturbance, and to be a partial wave follower at low frequencies. The relative location of the interface is measured by an array of 8 capacitance wave staffs, while the motion of the buoy is monitored using linear accelerometers and rate gyros. This combination permits high resolution measurement of wave directional properties from 10 cm to 600 m. We compare directional frequency spectra measured from the ASIS buoy with those obtained from a 3-meter discus buoy located roughly 1 km away.