Arctic Profiling Mooring Array for the Beaufort Shelf Observing System
OCCI Funded Project: 2005
Proposed ResearchIn this project we plan to deploy a high-resolution profiling mooring in the core of the Beaufort boundary current, approximately 150 kilometers east of Barrow Canyon in the Arctic Ocean. The dynamics of the boundary current system in the Beaufort Sea are principally responsible for the shelf-basin exchange in the western Arctic. An array in this location is optimal, because it will measure the cumulative outflow of Pacific water from all three branches exiting the Chukchi Sea, where models and observations imply that a large offshore flux is taking place.
The four main objectives of the experiment are to: (1) quantify the mean and seasonally varying transport, structure and water mass content of the boundary current system downstream of the Chukchi Sea outflow points; (2) determine the nature and cause of the mesoscale variability of the boundary current, and assess the impact of the variability on the cross-stream exchange of mass and properties; (3) identify the dynamics of the secondary circulation; and (4) elucidate the source of the interior eddies by comparing the seasonally changing boundary current water to the observed characteristics of the mid-basin eddy field. Meeting these objectives will fundamentally advance our understanding of the nature and cause of shelf-basin exchange in the Arctic Ocean and, thereby, elucidate how this high-latitude ocean will respond to variable climatic forcing.
The mooring will be a “full service” device that will provide:
- Temperature and salinity profiles from the bottom to the surface multiple times per day, including the heretofore-unmeasured top 40 meters of the water column. WHOI is the first to do this in the Arctic Ocean. The top part of the water column will be profiled using the new generation Arctic winch. The sensor unit on the winch will transfer the data after each profile to a data-logger on the top float, ensuring that no data will be lost, should the winch get snagged in the ice.
- A velocity profile every hour from a bottom-mounted acoustic Doppler current profiler (ADCP). This unit will also provide the velocity of the ice above the mooring.
- Data on the thickness of the ice using an upward-looking sonar attached to the top float. Understanding the growth, thickness, and movement of the ice is crucial for studies of local convection and halocline ventilation.
- A measurement of bottom pressure, important for Arctic tides and sea-level studies.