Pacific Water Pathway in the Arctic Ocean and Beaufort Gyre in Two Simulations With Different Horizontal Resolutions

Abstract

AbstractA set of numerical simulations (with horizontal resolutions of 1/4° and 1/12°) is conducted to study the Pacific Water pathway in the Arctic Ocean and the freshwater content in Beaufort Gyre. Passive tracer tags the Pacific Water entering through Bering Strait into the Arctic Ocean and further reveals its circulation routes and spatial distribution. Both the 1/4° and 1/12° simulations show Pacific Water mainly follows the Transpolar Drift over the integration period of 2002–2016, with a limited amount being able to flow eastward along the Alaskan coast to enter the Canadian Arctic Archipelago. However, the circulation pattern of Pacific Water within the Beaufort Gyre is quite different with a stronger and tighter anticyclonic circulation in the 1/12° simulation corresponding to the difference in freshwater content. The 1/12° simulation successfully reproduces the overall recent increasing trend in the freshwater content in the Beaufort Gyre, while the 1/4° simulation fails to maintain the high freshwater content state after 2007. Budget analysis suggests that this difference in Beaufort Gyre freshwater storage is mainly caused by lateral advection. The lateral freshwater flux is decomposed into two components due to the slow‐varying circulation and mesoscale eddies. The difference in the capability to resolve eddies in the two simulations causes the difference in the temporal evolution of both components of the lateral flux.