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

University Of Washington, Seattle WA

Investigators

Abstract

The focus of this five-year program is to assess the seasonal and interannual physical and biological variability of the Alaska Coastal Current (ACC). Specifically the PIs will investigate the seasonal and interannual variability in ACC freshwater content and transport, the ACC's role in governing spring-time mixed layer evolution over the shelf, processes controlling temporal and spatial variability in the spring bloom, and processes that may produce onshore nutrient flux. These processes are inherently three-dimensional and exhibit a wide range of temporal scales. To address these sampling requirements, this program will exploit the capabilities of a new, autonomous, telemetering vehicle (Seaglider) to make continuous, high-resolution sections of the ACC. Seaglider measures temperature, conductivity, pressure, chlorophyll fluorescence, dissolved oxygen and volume scattering function, profiles from the surface to within 10 m, of the bottom and provides 2 km horizontal resolution. The vehicle will operate year-round, repeating a sampling pattern designed to provide five sections across the ACC every twenty days. The sampling strategy was designed to augment existing GLOBEC Long Term Observation Program components. The temporal and spatial resolution provided by Seaglider surveys will resolve processes such as springtime restratification and phytoplankton blooms, while the multi-year extent of these observations will explore the system's response to long timescale perturbations in forcing.