Impact of ocean mesoscale on HEAT transport UP to sea ice in the Arctic and Antarctic – HEAT-UP

Both the Arctic and Antarctic sea ice are currently retreating and are predicted to further shrink into the 21st century. Reductions in sea ice have major implications on the climate, the ecosystems, and on human societies. Reliable projections of sea ice are thus crucial to help our societies in making informed decisions for climate change mitigation and adaptation. The sea ice retreat is due in part to the ocean that brings relatively warm waters from the low to the high latitudes. In particular, mesoscale processes (10-100 km) are thought to play a determining role in transporting heat towards polar regions. Yet, it remains unclear how ocean mesoscale impacts the pathways of these warm waters en route to the poles, the magnitude and variability of poleward heat transport, and how it contributes to transferring this heat up to the sea ice. This knowledge gap is due to the sparsity of observations in polar regions and the limited resolution of numerical models at high latitudes. By using high-resolution ocean-sea ice models, the HEAT-UP project proposes to advance our understanding of the role of the ocean mesoscale on heat transport from the subpolar regions to the sea ice in both hemispheres. This focus on the two poles will leverage similarities between the two polar regions within a consistent methodological framework to make advances on the characterization and quantification of the impact of mesoscale processes on heat transport in the context of sea ice decline. Doing so, the project will inform the development of parameterizations of mesoscale processes in ocean models and the interpretation and deployment of observations in polar regions.