EAS Seminar: Jessica Mejia (Syracuse)

Description

The Greenland Ice Sheet is a major contributor to global sea level rise, driven by both increased melting and dynamic ice discharge into the ocean. While often treated separately, these processes are interconnected because when surface meltwater flows into crevasses—cracks on the ice sheet surface—they can hydrofracture through the entire ice sheet and reach the bed. Once surface meltwater reaches the ice-bedrock interface it can modulate subglacial water pressures, the structure of the subglacial drainage system, and influence ice dynamics (sliding speeds). In this talk I will focus on recent work understanding these hydraulic connections. First, I will discuss how far inland these hydraulic connections can extend into the ice sheet’s interior using coupled observational, remote sensing, and modeling applied to the firn aquifer on Helheim Glacier in southeast Greenland. Next, I will discuss in situ observations of crevasse opening and what it means for firn aquifer drainage. Finally, I will discuss some modeling work applied to rapid hydraulically driven fracture propagation from the fast drainage of supraglacial lakes on the Greenland Ice Sheet.
 

Bio:
Jessica Mejia is an assistant professor of cryosphere and polar sciences in the Department of Earth and Environmental Sciences at Syracuse University. She received her M.S. in geophysics in 2016 from the University of Alaska Fairbanks, and her Ph.D. in geology in 2021 from the University of South Florida. Her research interests focus on understanding how water interacts with glaciers and ice sheets to affect ice flow, primarily focusing on observational, field-based methods (hydrologic, geodetic, and geophysical), process-based models, and remote sensing to study the structure and evolution of the glacial hydraulic system and the physical processes controlling hydro-dynamic coupling on the Greenland Ice Sheet.