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

Abstract

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.

An analysis of Atlantic Water in the Arctic Ocean using the Arctic Subpolar Gyre State Estimate and observations

“…Since the -plane approximation (constant ) can be applied to the Arctic, PV contours closely follow isobaths. As discussed in Timmermans and Marshall, 2020 [11], the integral of the wind stress curl within an enclosed / contour may be related to the circulation around that contour and results in an AW Layer that is driven by the wind stresses in the Nordic Sea. Thus, forcing external to the AO could be resulting in the surge observed within ASTE.…”

“…Inflow from the Atlantic Ocean via the Nordic Seas occurs in two main branches: one traversing the Fram Strait between Svalbard and Greenland and the other passing through the northern Barents Sea as shown in Figure 1 which AW interacts with adjacent water layers [11].…”

“…Streamlines for the mean AW Layer velocity from January 2010 through December 2017.Water mass transformation within the AO has been discussed as an important driver for AW flow into the AO[11]. To view the overturning circulation within ASTE, the AO is divided into three layers: a Surface Layer, the AW Layer, and a Bottom Layer.…”

The changing Arctic Ocean: consequences for biological communities, biogeochemical processes and ecosystem functioning

“…[2][3][4][5]). Significant changes in the type, extent and thickness of ice cover [6], meltwater input [7] and water mass dynamics [8], coupled with warming and ocean acidification [9], have already begun to impact ecosystem processes and the flora and fauna that inhabit a range of Arctic habitats [10]. The pace of change is such that our understanding of the way in which Arctic systems are structured and function is outdated, and insufficient to inform management, mitigation and adaptation efforts across the region [11,12].…”

Temporal Variability of Internal Wave‐Driven Mixing in Two Distinct Regions of the Arctic Ocean

“…While topography associated with the sharp Mackenzie shelf break promotes the generation of energetic IWs (Kulikov et al, 2010), the Beaufort Sea is also well-known for its high stratification relative to other regions of the Arctic Ocean, to which Guthrie et al (2013) attribute the weak IW-driven mixing rates that they estimate in this region. The strength of stratification is in part a result of sustained surface Ekman convergence of freshwater deriving from river discharge, net precipitation, and sea ice melt, which results in strong stratification at the mixed layer base (Timmermans & Marshall, 2020). Deeper in the water column, it is also set by the layering of distinct water masses present in the system that are sourced both within and outside of the Arctic Ocean (Carmack et al, 1989;Lansard et al, 2012).…”