The Beaufort Gyre extent, shape, and location between 2003 and 2014 from satellite observations

• Published in: Journal of Geophysical Research: Oceans
• Main Authors: Regan, Heather, Lique, Camille, Armitage, Thomas W. K.
• Format: Article in Journal/Newspaper
• Language: English
• Published: American Geophysical Union (AGU) 2019
• Subjects: Arctic oceanography; Beaufort Gyre; dynamic ocean topography; freshwater; Arctic; Arctic Ocean; Canada; Beaufort Sea; canada basin; Chukchi; North Atlantic; Sea ice
• Online Access: https://archimer.ifremer.fr/doc/00476/58763/61302.pdf; https://doi.org/10.1029/2018JC014379; https://archimer.ifremer.fr/doc/00476/58763/

The Beaufort Gyre is a significant reservoir of freshwater in the Arctic. It is thought to play a key role in regulating Arctic freshwater discharge to the North Atlantic, and in recent decades its freshwater content has increased in a time of rapid Arctic change. Despite this, its exact dynamical behaviour is not fully understood. Here, we make use of an Arctic‐wide dataset of Dynamic Ocean Topography (DOT), including data under sea ice, to characterise the time‐varying extent, shape, and location of the Beaufort Gyre. We show that the gyre expanded towards the north‐west between 2003 and 2014, resulting in increased proximity to the Chukchi Plateau and Mendeleev Ridge by 2014. We find that the gyre strength and maximum DOT both respond readily to changes in intensity of the surface forcing, but the gyre area is additionally affected by the location of the Beaufort Sea High. This results in expansion over the Chukchi Plateau and increased asymmetry of the gyre as it becomes constrained by the shallow bathymetry. The gyre strength is correlated with the integrated surface stress on the ocean over the previous 3 months. We discuss the implications of the expansion over shallow bathymetry on gyre dynamical behaviour and the potential impacts on the physical properties in the Canada Basin. Plain Language Summary The Beaufort Gyre, in the Canadian Basin of the Arctic Ocean, contains a large amount of the total freshwater held in the Arctic, and is thought to be important in controlling freshwater exported out into the North Atlantic and thus affects the oceanography there. Recently, the freshwater in the gyre has increased, but the gyre itself and the effect of this change are not well understood. We use a satellite dataset to describe, in detail, the size, shape and position of the gyre, and how it changed over 2003‐2014. We found that whilst the gyre circulation increases when winds strengthen, the spatial distribution of the winds also affects the position of the gyre, and years with continuously strong or weak winds have more effect than short‐lived events. The gyre expanded towards the northwest until it reached shallow bathymetry, which limited free expansion and caused its shape to become asymmetrical. We discuss the potential effects of this on the gyre's circulation and freshwater storage, as well as impacts on the surrounding ocean.