Directional Buoys

During the 1990s, CDIP gradually replaced all of its non-directional buoys with directional buoys manufactured by Datawell. These buoys use hippy heave-pitch-roll sensors to measure wave direction as well as wave energy. They also have a pair of horizontal accelerometers for measuring north/south and east/west displacements. This translational system uses pitch-roll to correct the buoy movement to a fixed x-y-z reference frame; it has a better signal-to-noise ratio than buoys that use pitch-roll directly to estimate directional wave properties.

Datawell’s Directional Waverider buoy is now the primary instrument deployed and operated by CDIP. Like the non-directional Waverider, it effectively measures waves with periods from 1.6 to 30 seconds, with an error of no more than 3%. It also measures wave direction and sea surface temperature. The temperature sensor is located at the base of the .9 meter spherical buoy, approximately 45 cm or 18 inches below the surface. In accordance with IALA standards, the buoys are equipped with a light that flashes 5 times in a 20-second cycle (5 flashes 2 seconds apart, followed by a 12-second pause).

(Source: California Information Data Project – http://cdip.ucsd.edu/?sub=index&nav=documents&xitem=gauge)