Changing Sources and Pathways of Freshwater Accumulation in the Arctic Ocean

Changsheng Chen1, Yu Zhang2, Robert C Beardsley3, Sylvia T Cole4, Guoping Gao5 and Huichan Lin1, (1)University of Massachusetts Dartmouth, New Bedford, MA, United States, (2)Shanghai Ocean University, College of Marine Sciences, Lingang, China, (3)WHOI, Woods Hole, MA, United States, (4)WHOI, Woods Hole, United States, (5)Shanghai Ocean University, College of Marine Sciences, Shanghai, China
Abstract:
One of the most striking observations in the Beaufort Gyre (BG) region in the Arctic has been a reduction in both sea ice extent and thickness together with fresh seawater accumulation. Insights into recent changes of freshwater content have been examined intensively in particular years and under different conditions, but studies do not agree on the major causes and consequences of freshwater accumulation in the BG region. A high-resolution geometrical-fitting model (AO-FVCOM) was developed for the Arctic Ocean. The 39-year simulation results reveal that as increase of freshwater runoff due to glacier mass changes and a large variability of sea ice melting, the coastal flow in the Arctic has dramatically changed in the last decade. In addition to local Ekman pumping, the coastal and slope flows are becoming a major source and pathway for the unprecedented freshwater accumulation in BG region, with short-term variation attributing to the increase of freshwater runoff over the North American coast and long-term variation influenced by the intensification of the slope flow remotely from the European coast. The inflow from Bering Strait is one of major sources for water entering the Arctic but not a key physical process causing freshwater accumulation in the BG region.