Multiple factors affect the glacier, such as snow, winds, calving fronts, Circumpolar Deep Water (CDW), and the Amundsen Sea Low (ASL). (Figure from Ted Scambos, ITGC website)
Cartoon showing active-source seismic methods used to image the glacier and the rock-ice interface. Figure from Adam Booth and others.
Collaborating scientists in the U.S. include research groups led by Dr. Marianne Karplus, Galen Kaip, and Dr. Steve Harder at the University of Texas at El Paso, Dr. Slawek Tulaczyk at University of California Santa Cruz, Dr. Jenny Suckale and Dr. Dustin Schroeder at Stanford University, Dr. Jake Walter at University of Oklahoma, Dr. Nori Nakata at MIT. Collaborators in the UK include Dr. Adam Booth at Leeds, Dr. Poul Christoffersen and Dr. Marion Bougamont at Cambridge.
Thwaites Interdisciplinary Margin Evolution (TIME) Project
TIME is one of 9 NSF and NERC-funded projects that make up the International Thwaites Glacier Collaboration (ITGC) effort to better understand Thwaites Glacier in West Antarctica -- especially how fast it is melting and how much it could contribute to sea level rise in the future. TIME is particularly focused on the Eastern Shear Margin of Thwaites Glacier, where the ice transitions from fast-moving (>100 m/yr) on Thwaites Glacier to almost stationary off of the glacier.
In order to better understand the glacier structure, melt rates, and processes, it is important to study the ocean-ice interactions, ice-ice interactions, and ice-rock interactions and conditions that control the movement and melting of the glacier. Seismic imaging of glaciers involves looking at vibrations traveling through rock and ice to determine rock and ice properties such as the speeds of seismic waves (which relate to density and fluid content), where seismic waves reflect and refract, the attenuation of seismic waves, and other material properties of the rock and ice that affect the wave propagation.
To study the Shear Margin of Thwaites, the TIME project includes active-source seismic imaging (uses a man-made source), passive-source seismic recording (listening for non-man-made vibration sources like earthquakes, icequakes, crevasses opening, fluids moving within or beneath the glacier, etc.), radar imaging, GPS monitoring of glacier flow, and several types of ice sheet modeling. The close integration of new field data with computer modeling efforts is expected to lead to exciting results and greatly increase our understanding of this glacier. The UTEP TIME team is focused on the active-source seismic imaging part of the project.
The West Antarctic Ice Sheet (WAIS) contains 2 million cubic kilometers of ice and the global scientific community considers it the most significant risk for coastal environments and cities facing future sea level rise. The risk posed by the WAIS arises from its deep, marine-based setting, with ice situated on reverse bed slopes prone to significant and prolonged retreat. Although scientists have been aware of the precarious setting of the WAIS since the early 1970s, it is only now becoming apparent that the flow of ice in several large drainage basins is undergoing dynamic change, which is consistent with, although not certain to be, the inception of a prolonged and potentially unstoppable disintegration. Understanding WAIS stability and enabling more accurate prediction of sea level rise through realistic simulation of ice flow in large-scale models are two of the fundamental global challenges facing the scientific community today. In TIME, we directly address both challenges by A) using frontier technologies to observe rapidly deforming shear margins hypothesized to exert strong control on the future evolution of Thwaites Glacier, and B) using observational record to develop parameterizations for important processes which are not yet implemented in ice sheet models used to predict WAIS contribution to sea level rise.
Check out the UTEP TIME 2018-19 field blog written by Marianne Karplus!
Publications & Presentations
We are processing the data from the 2018-19 field season. Stay tuned!