Numerical Investigation of Diapycnal Mixing of the Kitikmeot Sea in the Southern Canadian Arctic Archipelago

Abstract

ABSTRACT Utilizing a 1 / 12 ∘ numerical model, we examine the diapycnal mixing patterns in the Kitikmeot Sea, a semi-enclosed water body within the southern Canadian Arctic Archipelago. The analysis reveals that mixing intensity near the sea surface varies seasonally, with effective diffusivity values ranging from 10 − 5 to 10 − 3 m 2 s − 1 , while away from the surface, the effective diffusivity remains relatively stable between 10 − 5 and 10 − 4 m 2 s − 1 . The seasonal fluctuations in surface mixing intensity are strongly influenced by ice coverage, which impacts both the stratification and the energy input to the surface driving the mixing process. Mixing energetics analysis indicates that the majority of energy contributing to the mixing processes are applied to the sea surface. During ice-free periods, wind-driven stirring dominates near-surface mixing with effective diffusivities of 10 − 5 to 10 − 4 m 2 s − 1 . Minimum near-surface effective diffusivity values occur in July and August, when the surface water is fresher and near-surface stratification is stronger due to spring freshet. Conversely, during ice-covered seasons, surface cooling and brine rejection primarily drive near-surface mixing, leading to effective diffusivities of 10 − 3 m 2 s − 1 or higher. In most cases, the observed mixing efficiency is within the range of what has been found in other regions of the Arctic Ocean.