Freshwater Export from the Arctic Ocean and its Downstream Effect on Labrador Sea Deep Convection in a High-Resolution Numerical Model

• Main Author: McGeehan, Timothy P.
• Other Authors: NAVAL POSTGRADUATE SCHOOL MONTEREY CA
• Format: Text
• Language: English
• Published: 2010
• Subjects: Physical and Dynamic Oceanography; *ARCTIC OCEAN; *LABRADOR SEA; GLOBAL; OCEAN SURFACE; CANADA; CONVECTION; HIGH RESOLUTION; FRESH WATER; ICE; SCALE; CLIMATE; HYPOTHESES; SALINITY; CIRCULATION; DEEP OCEANS; SEA ICE; OPEN WATER; ARCTIC REGIONS; SALT WATER; ARCHIPELAGOES; BAFFIN BAY; SPATIAL DISTRIBUTION; THERMAL PROPERTIES; MATHEMATICAL MODELS; Arctic; Arctic Ocean; Baffin Bay; Canada; Canadian Arctic Archipelago; Northwest Passage; Arctic Archipelago; Baffin; Davis Strait; Labrador Sea; Northwest passage; Sea ice
• Online Access: http://www.dtic.mil/docs/citations/ADA536542; http://oai.dtic.mil/oai/oai?&verb=getRecord&metadataPrefix=html&identifier=ADA536542

The Labrador Sea is one of the only known locations of deep open ocean convection, a process determined to play a significant role in regulating global thermohaline circulation and climate. The main hypothesis of this study is that low salinity water from the Arctic Ocean, particularly outflow through the Canadian Arctic Archipelago (CAA), may affect Labrador Sea deep convection. To address it, output from a pan-Arctic high-resolution coupled ice-ocean model was examined. Volume and freshwater fluxes through the CAA for 1979-2004 were found in good agreement with the observations. Further analyses suggest that the flow through the major CAA channels depends on the sea surface height gradient between the Arctic Ocean and northern Baffin Bay. Freshwater flux anomalies entering the Labrador Sea through Davis Strait do not immediately affect deep convection. Instead, eddies and sea ice acting on shorter time scales can move freshwater to locations of active convection and halt the process, which underscores the importance of high-resolution. Also, changing ice conditions revealed the Northwest Passage was a possible shipping route in three summers. Finally, preliminary results from an eddy-resolving model configuration suggest that many of the shortcomings in this model may be rectified with higher spatial resolution.