Arctic pathways of Pacific Water: Arctic Ocean Model Intercomparison experiments

Area of Science:

• Oceanography
• Climate Science
• Arctic Studies

Background:

• Pacific Water (PW) influx through Bering Strait is crucial for Arctic Ocean heat, freshwater, and nutrient budgets.
• The precise circulation pathways of PW within the central Arctic Ocean remain poorly understood due to limited observational data.

Purpose of the Study:

• To investigate and delineate the primary pathways of Pacific Water circulation in the central Arctic Ocean.
• To utilize advanced Ocean General Circulation Models (OGCMs) to simulate and analyze PW transport.

Main Methods:

• Employing six state-of-the-art regional and global Ocean General Circulation Models (OGCMs).
• Utilizing a passive tracer released in the Bering Strait to track the movement of Pacific Water.
• Analyzing simulated PW distribution and identifying distinct circulation branches.

Main Results:

• PW spreads from the Bering Strait in three major simulated branches.
• Branch 1: Barrow Canyon, along Alaska's slope to Canadian Straits and Baffin Bay.
• Branch 2: Herald Canyon, along the East Siberian Sea slope into the Transpolar Drift, Fram Strait, and Greenland Sea.
• Branch 3: Herald Shoal/Chukchi shelf into the Beaufort Gyre.
• Wind-driven Ekman pumping significantly influences seasonal and interannual variability of PW in the Canadian Basin, affecting flow vorticity.

Conclusions:

• The study successfully identifies three distinct pathways for Pacific Water circulation in the Arctic Ocean using OGCMs.
• Wind forcing, particularly Ekman pumping, plays a critical role in modulating the variability of PW within the Canadian Basin.
• These findings enhance our understanding of Pacific Water's role in the central Arctic Ocean's dynamics and heat transport.