Seasonal and Interannual Variability of the Alaska Coastal Current: Long-Term, Three-Dimensional Observations using a Telemetering, Autonomous Vehicle

PI: Craig M. Lee and Charles C. Eriksen
Sponsor: National Science Foundation ()

As part of the U.S. GLOBEC Northeast Pacific program, repeated Seaglider surveys will characterize the seasonal and interannual variability of the Alaska coastal Current (ACC). The dynamics of the Alaska Coastal Current (ACC) govern stratification and circulation over the inner portion of the Alaskan shelf, a region that plays a critical role in the early life history of several commercially important fish species, including juvenile salmon. The system responds strongly to large seasonal and interannual changes in freshwater discharge and wind-forcing. Moreover, seasonal shifts in dynamics likely exert strong influences on the temporal and spatial structure of stratification, on the spring phytoplankton bloom and on the advective transport of zooplankton and fish. Seasonal cycles in dynamics may also play a key role in explaining how nutrients are replenished in this downwelling-favorable system that is inundated by nutrient-depleted freshwater discharge. Thus, variability in wind-forcing and freshwater discharge produce significant changes in ACC dynamics which can influence the recruitment success of zooplankton and fish through a number of different pathways.