NSF Award
2419987
The Antarctic ice sheet contains the world’s largest amount of fresh water and has the potential to become the greatest contributor to future global sea level rise. The dominant mechanism by which Antarctica currently loses mass is ice discharge, where ice on the continent flows into the ocean. Ice shelves are floating extensions of land ice that surround 75% of the Antarctic Ice Sheet and restrain continental ice from reaching the ocean. Therefore, understanding the processes that cause ice shelves to break apart is key to reducing uncertainty in how much and how quickly sea level will rise. Observational evidence demonstrates that liquid water on ice shelves, typically from surface melting, can sometimes lead to their collapse. Seawater infiltration into porous ice shelf firn (perennially-persistent porous snow that has not yet compacted into ice) is another pathway for water to access ice shelves; however, the impacts of this process on ice shelf stability remain understudied across Antarctica. Constraining the impact of seawater infiltration on ice shelf stability requires a better understanding of the total extent of ice shelves affected, the internal structure of these water bodies, and the total volume of liquid water stored. The project will include participation from undergraduate student researchers from the Cornell GeoPaths Geoscience Learning Ecosystem (CorGGLE) and develop a hands-on radioglaciology workshop for early-career researchers.<br/><br/>The project will characterize the extent and morphology of seawater/brine aquifers across Antarctic ice shelves by utilizing approximately 180,000 kilometers of existing airborne ice penetrating radar data. The researcher will (1) adapt previous semiautomatic meltwater firn aquifer detection algorithms to map the extent of brine aquifers across ice shelves where there is available radar data; (2) use radar attenuation and reflectivity models to estimate the liquid water volume of brine aquifers; (3) utilize satellite imagery, surface digital elevation models, and ice thickness datasets to determine where and how seawater infiltrates ice shelf firn; and (4) integrate radar data with ice shelf stratigraphy models to estimate the persistence of deep entrained brine layers and constrain their potential impacts on ice rheology. This project will clarify the relative importance of brine aquifers in the ice shelf system and their potential to impact ice shelf stability. It will also produce new datasets needed to constrain future ice shelf hydrology and hydrofracture models that will determine the full influence of these systems.<br/><br/>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.
