Characterizing the Transport Pathways and Storage of Freshwater in the Western Arctic Ocean Through a HYCOM-Based Drifter Study

The Beaufort Gyre (BG) stores the majority of the Arctic's freshwater content and since 1997 has accumulated an unusually large freshwater surplus. When it eventually releases its surplus freshwater, a salinity anomaly similar to the Great Salinity Anomaly could occur, with far-reaching climatic effects. This presentation aims to characterize the freshwater transport pathways into and out of the BG, with particular focus on the Mackenzie Bay region. The study is based on analysis of virtual drifters in the Navy's HYbrid Coordinate Ocean Model (HYCOM). Two drifter release locations in Mackenzie Bay and in the lower Beaufort Gyre, adjacent to the Canadian Arctic Archipelago, were chosen, and simulations were run using HYCOM data spanning 2015 to 2018. The study found that the behavior of drifters exiting the Mackenzie Bay varied more from year to year than it did seasonally, and that the northeastward current along the Barrow Canyon influenced how quickly drifters entered the gyre. Drifters originating in the BG tended to circulate in the lower BG and exited the western Arctic through the Canadian Arctic Archipelago. The BG simulations appeared to be more dependent on seasonal wind and current variations than the Mackenzie Bay drifters had been. This study could be used to predict when the BG is likely to take up more freshwater, and what areas may be affected by a salinity anomaly when the BG releases its surplus freshwater.