Collaborative Research: Constraining the Role of the Antarctic Slope Current on Tracer Exchange at the Antarctic Margin using Model Hierarchies

The Southern Ocean (SO) plays a dominant role in the climate system, accounting for a disproportionate amount of anthropogenic heat and carbon uptake and determining how the largest source of potential future sea level rise, the Antarctic Ice Sheet (AIS), evolves. Therefore, dynamics in the SO have an outsized role in the climate system and the trajectory of climate change and associated societal impacts. The swift westward flowing Antarctic Slope Current (ASC) that moves along the boundary between the Antarctic continental shelf and the open SO is hypothesized to influence heat delivery to Antarctic ice shelves, suggesting an important mechanism for controlling AIS melt rates and thus future sea level rise. The ASC also may act as a key gateway for the exchange of nutrients and carbon between the shelf and open SO, with implications for the marine carbon cycle and ecosystem dynamics. To constrain how the thermal and biogeochemical properties of the Antarctic shelf and open SO will evolve, a comprehensive understanding of the ASC, its variability, its role in tracer transport, and its response to internal and external climate forcing is required. Despite its hypothesized importance, beyond sub-annual timescales and at localized regions, critical knowledge gaps exist in our understanding of the ASC. The proposed research will utilize a hierarchy of state-of-the-science observationally-constrained and validated physical and biogeochemical SO state estimates and fully-coupled climate model simulations to address these existing knowledge gaps. A novel, fine-resolution Southern Ocean State Estimate (SOSE) with tidal forcing, ice shelf cavities, and thermodynamically-active ice shelves will allow for the investigation of the connection between ASC variability and ice shelf melt events. The results from this work will provide foundational knowledge on the ASC’s climatological state and structure, its variability, and its role in the evolving climate system. This research will also provide critical insight on the role that model resolution may play in ASC dynamics, a step which is vital for improving the fidelity of model simulations and future projections. In addition to engaging with the Temple University First-Generation Initiative for recruiting early career researchers, a partnership with the Compute-STEM program to develop lesson plans and teacher trainings will extend the impacts of this research project. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.