Pan‐Antarctic Assessment of Ice Shelf Flexural Responses to Ocean Waves.

Understanding the drivers of iceberg calving from Antarctic ice shelves is important for future sea level rise projections. Ocean waves promote calving by imposing stresses and strains on the shelves. Previous modeling studies of ice shelf responses to ocean waves have focused on highly idealized geometries with uniform ice thickness and a flat seabed. This study leverages on a recently developed mathematical model that incorporates spatially varying geometries, combined with measured ice shelf thickness and seabed profiles, to conduct a statistical assessment of how 15 Antarctic ice shelves respond to ocean waves over a broad range of relevant wave periods, from swell to infragravity waves to very long period waves. The results show the most extreme responses at a given wave period are generated by features in the ice shelves and/or seabed geometries, depending on the wave regime. Relationships are determined between the median ice shelf response and the median shelf front thickness or the median water cavity depth. The findings provide further evidence of the role of ocean waves in large‐scale calving events for certain ice shelves (particularly the Wilkins) and indicate a possible role of ocean waves in calving events for other shelves (Larsen C and Conger). Further, the relationships determined provide a method to assess the potential for increased calving as ice shelves evolve with climate change, and, hence, contribute to assessments of future sea level rise. Plain Language Summary: Antarctic ice shelves are the floating extensions of the Antarctic Ice Sheet. They play a critical role in many Southern Ocean processes. In particular, they help maintain the stability of the Antarctic Ice Sheet by moderating the flow of grounded ice into the Southern Ocean. Climate change is causing them to thin and retreat, which is a major threat to global sea levels. Iceberg calving accounts for half of ice shelf loss, and ocean waves contribute to the calving process by rhythmically bending ice shelves. The influence of ocean waves on calving is expected to increase as the shelves and their surrounding sea ice barriers become weaker. Therefore, quantifying the responses of ice shelves to ocean waves is needed to project the future of the shelves and, hence, sea level rise. In this study, we use a recently developed mathematical model to analyze the responses of 15 Antarctic ice shelves to ocean waves, ranging from storm waves to tsunamis. We show how features in the geometry can create large responses that could drive calving events, and we derive simple relationships between the responses and the geometry to aid projections of future scenarios. Key Points: Crevasses and seabed protrusions create large ice shelf flexure in response to ocean wavesIce shelves that have experienced large scale calving events had much greater responses to swell than typical shelvesMedian ice shelf responses to swell are strongly correlated to median shelf front thicknesses [ABSTRACT FROM AUTHOR]