Mesoscale variability in the boundary currents of the Alaska Gyre

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Measurements of sea-surface height anomalies acquired during the GEOSAT, ERS-1, and TOPEX altimeter missions show that the boundary currents of the Alaska gyre exhibit interannual variability with respect to the occurrence, size, and propagation of mesoscale, eddy-like features. Observations and model results suggest that eddies are generated in the Alaska Current during years in which the wind forcing in the eastern Gulf of Alaska promotes strong downwelling along the British Columbia–Alaska coast. Wind forcing conditions that support eddy formation and intensification often occur in years that coincide with El Niño–Southern Oscillation events. Eddy variability is significantly more deterministic in the Alaska Current than in the Alaskan Stream.