Instrument: Beardsley Drifter

Beardsley Drifters are near-surface satellite-tracked drifters used for observations of circulation patterns. They are WOCE-style drifters featuring holey sock drogues. Each drifter has a small (~ 30 cm diameter) surface float with ARGOS transmitter and batteries tethered to a holey sock drogue centered at 15 m below the surface. The drogue, about 10 m tall and 1 m in diameter, is designed to "lock" itself to the water so that the surface float follows the mean water motion at 15 m depth with very little slippage even in high winds. Thus measuring the drifter's position as a function of time provides a Lagrangian measurement of the 15-m ocean current.