UC Irvine

This study investigates the dynamics of marine-terminating glaciers in Greenland, with a focus on Jakobshavn Isbr\ae and Helheim Glacier, to better understand the processes driving their rapid retreat and contribution to global sea level rise. The Greenland Ice Sheet has seen a marked increase in ice mass loss over recent decades, primarily driven by accelerated glacier flow, enhanced surface melting, and complex ice-ocean interactions. Despite its significance, the mechanisms behind iceberg calving and the role of basal melting in these glaciers are not fully understood and are inadequately represented in current ice sheet models.

Using high-resolution Terrestrial Radar Interferometry (TRI), this research provides new insights into the grounding line migrations and bed topography of these key glaciers. The study reveals that both Jakobshavn Isbr\ae and Helheim Glacier exhibit significant grounding line migration in response to tidal forces, driven by seawater intrusions beneath the ice. In Jakobshavn Isbr\ae, the glacier’s bed topography is found to be up to 800 meters deeper than previously estimated, which, coupled with the extensive tidal-driven migration, indicates a higher sensitivity to ocean warming. Helheim Glacier, on the other hand, demonstrates a complex pattern at its ice front, characterized by a bi-polar seesaw movement due to the presence of a ridge in the middle of the fjord. This movement is driven by tidal displacement, which plays a critical role in influencing the glacier's calving dynamics.

The integration of TRI data with ice sheet models enhances the understanding of calving dynamics and refines the representation of ice-ocean interactions in predictive models. The findings underscore the importance of high temporal resolution monitoring and the need for improved bed topography data to reduce uncertainties in sea level rise projections. Additionally, the potential for incorporating upcoming satellite data, such as from the NASA-ISRO Synthetic Aperture Radar (NISAR) mission, is explored to further expand the capabilities of monitoring these critical processes. This study contributes to the broader cryospheric research by offering a more comprehensive understanding of the factors influencing glacier behavior in a warming climate, with implications for global sea level rise predictions.