Interannual variability of the Gulf of Alaska eddy field

Abstract

Regions of high eddy kinetic energy (EKE) in the Gulf of Alaska (GOA), calculated from altimetry data, denote formation regions and translation pathways for eddies. High EKE is observed along the shelf break in winter and spring with lower values in summer and autumn. Three regions of high EKE are examined in detail. In the eastern GOA, particularly high EKE occurred in 1998. In the northwestern GOA, eddies were observed quasi-annually between 1999 and 2004, but were less frequent prior to that time (or in 2005 and 2006). Eddies northeast of Kodiak Island have been implicated in high offshelf chlorophyll concentrations observed from ocean color satellites. Correlations between EKE and chlorophyll concentration are significant there suggesting that EKE may be valuable for predicting phytoplankton blooms in this region.