Mixing across the Arctic Ocean: Microstructure observations during the Beringia 2005 Expedition

Abstract

Turbulent‐scale temperature and conductivity were measured during the pan‐arctic Beringia 2005 Expedition. The rates of dissipation of thermal variance and diapycnal diffusivities are calculated along a section from Alaska to the North Pole, across deep flat basins (Canada and Makarov Basins) and steep ridges (Alpha‐Mendeleev and Lomonosov Ridges). The mixing rates are observed to be small relative to lower latitudes but also remarkably non‐uniform. Relatively elevated turbulence is found over deep topography, confirming the dominant role of bottom‐generated internal waves. Measured patterns of mixing in the Arctic are also associated with other mechanisms, such as double‐diffusive structures and deep overflows. A better knowledge of the distribution of mixing is essential to understand the dynamics of the changing Arctic environment.