Abstracts

Ice-anchored surface drifters have been used extensively in the Arctic during the last 50 years, but only a few include instrumentation below the ice. Here we describe upper ocean velocity observations from Ice-Ocean Environmental Buoys (IOEBs), special purpose platforms designed for long-term measurement of meteorological and oceanographic variables in the Arctic. Data were available from three IOEB deployments within the Beaufort Gyre between 1992 and 1998. The data are suitable for examining tides and near-inertial internal waves, but the dominant signal comes from subsurface eddies. Physical properties were determined for 81 eddies from 44 months of buoy drift. The majority of center depths were between 50 and 150 m and the mean vertical extent was 126 m. Thus, eddies were found predominantly within the cold halocline. Maximum rotation speeds were typically 20-30 cm/s, with some greater than 40 cm/s. Typical radii were 3-6 km. The sense of rotation was predominantly anticyclonic. Dynamical properties were determined for 29 eddies. Relative vorticity was maximum in the eddy cores, whereas strain was largest outside the radius of maximum velocity.