Sea Level Rise Seminar, 2025-05-06: Jessica Mejia

Sea Level Rise Seminar Tuesday May 6, 2025 Speaker: Jessica Mejia (Syracuse University) Title: Hydrology of the Greenland Ice Sheet: Impacts on Ice Dynamics and Sea Level Rise Abstract: The Greenland Ice Sheet is a major contributor to global sea level rise, driven by both enhanced surface melting and dynamic ice discharge into the ocean. Although often considered separately, these processes are tightly coupled: when surface meltwater enters crevasses, it can propagate through the full thickness of the ice sheet via hydrofracture, reaching the bed and influencing basal conditions. Once at the ice-bed interface, this meltwater can alter subglacial water pressures, reorganize the drainage system, and modulate ice flow dynamics. This presentation will explore the hydrology of the Greenland Ice Sheet from surface to bed, highlighting key processes including the routing of meltwater through supraglacial streams and rivers in the ablation area; the evolution of internally drained catchments and their temporal variability; the formation and function of moulins as vertical conduits linking surface and basal systems; the role of firn aquifers in the accumulation zone and their potential to drive hydrofracture in downstream crevasses; and the dynamic response of the subglacial drainage system to episodic and seasonal meltwater inputs. Together, these elements reveal the complex interplay between meltwater and ice dynamics, and their implications for future sea level rise.