The shedding of an anticyclonic eddy from the Alaskan Stream as observed by the Geosat altimeter

The evolution of a meander into an anticyclonic eddy which separates from the Alaskan Stream in the vicinity of the central Aleutian Islands is observed in two years of sea surface height anomalies computed from Geosat Exact Repeat Mission altimeter data. The observed region of meander growth and eddy separation agrees with that predicted by theory. Spin down times based on vorticity are much longer than those based on energies. This is consistent with an eddy's ability to maintain its integrity as it decays. Representative height, diameter, and velocity scales of the eddy are characteristic of rings spawned by other current systems. Assuming a ring structure for this eddy, the estimated ring volume represents a 21 percent transport anomaly referred to the mean annual transport into the Bering Sea.