Water Mass Modification and Mixing Rates in a 1/12 degree Simulation of the Canadian Arctic Archipelago

• Main Authors: Hughes, Kenneth G., Klymak, Jody M., Hu, Xianmin, Myers, Paul G.
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2017
• Subjects: Land-fast ice; Barrow Strait; Turbulence; Currents; Fluxes; Transport; Tides; Sound; Arctic; Canadian Arctic Archipelago; Queens Channel; Arctic Archipelago
• Online Access: https://era.library.ualberta.ca/items/2efe78bb-3056-4ca7-af4e-f25ed028c30d; https://doi.org/10.7939/r3-0bx4-kh10

Strong spatial differences in diapycnal mixing across the Canadian Arctic Archipelago are diagnosed in a 1/128 basin-scale model. Changes in mass flux between water flowing into or out of several regions are analyzed using a volume-integrated advection–diffusion equation, and focus is given to denser water, the direct advective flux of which is mediated by sills. The unknown in the mass budget, mixing strength, is a quantity seldom explored in other studies of the Archipelago, which typically focus on fluxes. Regionally averaged diapycnal diffusivities and buoyancy fluxes are up to an order of magnitude larger in the eastern half of the Archipelago relative to those in the west. Much of the elevated mixing is concentrated near sills in Queens Channel and Barrow Strait, with stronger mixing particularly evident in the net shifts of the densest water to lower densities as it traverses these constrictions. Associated with these shifts are areally averaged buoyancy fluxes up to 1028 m2 s23 through the 1027 kg m23 isopycnal surface, which lies at approximately 100 m depth. This value is similar in strength to the destabilizing buoyancy flux at the ocean surface during winter. Effective diffusivities estimated from the buoyancy fluxes can exceed 1024 m2 s 21 , but are often closer to 1025 m2 s 21 across the Archipelago. Tidal forcing, known to modulate mixing in the Archipelago, is not included in the model. Nevertheless, mixing metrics derived from our simulation are of the same order of magnitude as the few comparable observations.