Understanding Arctic Ocean Circulation: A Review of Ocean Dynamics in a Changing Climate

The Arctic Ocean is a focal point of climate change, with ocean warming, freshening, sea-ice decline, and circulation that link to the changing atmospheric and terrestrial environment. Major features of the Arctic and the interconnected nature of its wind- and buoyancy-driven circulation are reviewed here by presenting a synthesis of observational data interpreted from the perspective of geophysical fluid dynamics (GFD). The general circulation is seen to be the superposition of Atlantic Water flowing into and around the Arctic basin and the two main wind-driven circulation features of the interior stratified Arctic Ocean: the Transpolar Drift Stream and the Beaufort Gyre. The specific drivers of these systems, including wind forcing, ice-ocean interactions, and surface buoyancy fluxes, and their associated GFD are explored. The essential understanding guides an assessment of how Arctic Ocean structure and dynamics might fundamentally change as the Arctic warms, sea-ice cover declines, and the ice that remains becomes more mobile. Plain Language Summary The Arctic region is experiencing the most rapid environmental changes on Earth, with unparalleled air temperature increases, a warming ocean, and melting permafrost, snow, and ice. The ocean is a central control via Arctic Ocean warming, freshening, and circulation dynamics that link to the sea ice, atmosphere, and terrestrial environment. Given the rapid pace of Arctic change, it is vital to take stock of present understanding of the ocean circulation to address knowledge gaps and make viable future predictions. Present understanding of the principal geophysical fluid dynamics of Arctic Ocean circulation is synthesized here, and we speculate on how the dynamics of the ocean-ice-atmosphere system might change in a warming Arctic.