The horizontal and vertical variations of velocity, temperature, density, and turbulent kinetic energy dissipation in the central Beaufort Sea were measured with helicopter-borne expendable current profilers and conductivity-temperature-depth units. Almost all velocity differences larger than 0.05 m s-1 could be consistently interpreted as being due to nearly circular eddies with a diameter of 10--20 km, a thickness of 50--500 m, peak velocities of 0.07--0.3 m s-1, and little expression at the top of the ocean. Four such eddies were found. Two anticyclones were found and accurately sampled. Two cyclones were found but were only poorly sampled; both were beneath and close to one of the anticyclones. Relative vorticity could be computed for two anticyclones and one cyclone. Within experimental error, the two anticyclones, and all historical Beaufort Sea anticyclones, had a relative vorticity of -f and thus zero potential vorticity at the center. The cyclone had a central relative vorticity of about 0.5f and thus a different value of potential vorticity than the surrounding fluid. One anticyclonic eddy (B) was sampled seven times over a period of 23 days. Its measured velocity and density fields were in approximate gradient wind balance. Its central core contained values of temperature, nitrate, and silicate that were different from those outside the core at the same density. It moved eastward at about 0.02 m s-1 through the surrounding fluid. Measurements of turbulent kinetic energy dissipation were almost always less than the noise level of the instrument (about 10-9 W kg-1), corresponding to a mean dissipation much less than this and a minimum decay time due to turbulence much longer than 0.3 year.

The nondimensional strength (Rossby number) and shape (Burger number) of anticyclone B are very similar to those of other Beaufort Sea anticyclones and similar to those of small mid-latitude eddies. Each of the eddies observed here was centered on a temperature maximum associated with one of the warm water masses that advect into the Arctic Ocean. The two anticyclones were centered on temperature maxima originating in the Pacific Ocean, whereas the two cyclones were centered on temperature maxima from the Atlantic Ocean. This is consistent with the hypothesis that the eddies are formed as these water masses enter the Arctic Ocean. ¿ American Geophysical Union 1988