How does imposing an observationally-informed map of background vertical diffusivity impact the modelled Arctic Ocean state?

• Main Authors: O'Connor, B., Waterman, S., Scott, J., Dosser, H., Chanona, M.
• Format: Conference Object
• Language: English
• Published: 2023
• Subjects: Arctic; Arctic Ocean; Sea ice
• Online Access: https://gfzpublic.gfz-potsdam.de/pubman/item/item_5018913

Mixing in the Arctic Ocean drives water mass transformations critical to the heat and freshwater budgets of the Arctic Ocean, impacting sea ice, stratification, circulation, and heat and freshwater release to the subpolar N. Atlantic. Observations indicate that mixing rates in the Arctic Ocean are highly variable, however this variability is typically not well-represented in models. This study uses a regional Arctic Ocean model to addresses the question “How does imposing an observationally-informed map of background vertical diffusivity impact the modelled Arctic Ocean state?” It seeks to understand the impacts based on a set of model experiments that systematically vary the diffusivity uniformly in space. It is shown that prescribing the observationally-informed mixing map results in increased heat loss, a redistribution of freshwater storage, and increased heat and freshwater export to the N. Atlantic relative to a control case with an equal-on-average-but-spatially-uniform distribution of mixing. These effects can be understood as the result of enhancing (reducing) mixing on the shelves (basins) relative to the control case. They highlight sensitivities of the Arctic Ocean heat and freshwater budgets to shelf and basin mixing respectively.