USAP-DC

Earth's geologic record shows that the great ice sheets have contributed to rates of sea-level rise that have been much higher than those observed today. That said, some sectors of the current Antarctic ice sheet are losing mass at large and accelerating rates. One of the primary challenges for placing these recent and ongoing changes in the context of geologically historic rates, and for making projections decades to centuries into the future, is the difficulty of observing conditions and processes beneath the ice sheet. Whereas satellite observations allow tracking of the ice-surface velocity and elevation on the scale of glacier catchments to ice sheets, airborne ice-penetrating radar has been the only approach for assessing conditions on this scale beneath the ice. These radar observations have been made since the late 1960s, but, because many different instruments have been used, it is difficult to track change in subglacial conditions through time. This project will develop the technical tools and approaches required to cross-compare among these measurements and thus open up opportunities for tracking and understanding changes in the critical subglacial environment. Intertwined with the research and student training on this project will be an outreach education effort to provide middle school and high school students with improved resources and enhanced exposure to geophysical, glaciological, and remote-sensing topics through partnership with the National Science Olympiad.

The radar sounding of ice sheets is a powerful tool for glaciological science with broad applicability across a wide range of cryosphere problems and processes. Radar sounding data have been collected with extensive spatial and temporal coverage across the West Antarctic Ice Sheet, including areas where multiple surveys provide observations that span decades in time or entire cross-catchment ice-sheet sectors. However, one major obstacle to realizing the scientific potential of existing radar sounding observations in Antarctica is the lack of analysis approaches specifically developed for cross-instrument interpretation. Radar is also spatially limited and often has gaps of many tens of kilometers between data points. Further work is needed to investigate ways of extrapolating radar information beyond the flight lines. This project aims to directly address these barriers to full utilization of the collective Antarctic radar sounding record by developing a suite of processing and interpretation techniques to enable the synthesis of radar sounding data sets collected with systems that range from incoherent to coherent, single-channel to swath-imaging, and digital to optically-recorded radar sounders. This includes a geostatistical analysis of ice sheet and radar datasets to make probabilistic predictions of conditions at the bed. The approaches will be assessed for two target regions: the Amundsen Sea Embayment and the Siple Coast. All pre- and post-processed sounding data produced by this project will be publically hosted for use by the wider research community.

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.

Person	Role
Schroeder, Dustin	Investigator and contact
MacKie, Emma	Investigator

Antarctic Glaciology	Award # 1745137
Antarctic Instrumentation and Support	Award # 1745137

USAP-1745137_1

None in the Database

Repository	Title (link)	Format(s)	Status
USAP-DC	Antarctic topographic and subglacial lake geostatistical simulations	Not Provided	exists
USAP-DC	Radar Sounding Observations of the Amundsen Sea Embayment, 2004-2005	Not Provided	exists

1. MacKie, E. J., D. M. Schroeder, J. Caers, M. R. Siegfried and C. Scheidt, Matthew R. Siegfried. Antarctic Topographic Realizations and Geostatistical Modeling Used to Map Subglacial Lakes (in review).
2. Winter, K., Woodward, J., Ross, N., Dunning, S. A., Hein, A. S., Westoby, M. J., … Siegert, M. J. (2019). Radar‐Detected Englacial Debris in the West Antarctic Ice Sheet. Geophysical Research Letters, 46(17-18), 10454–10462. (doi:10.1029/2019gl084012)
3. MacKie, E. J., Schroeder, D. M., Caers, J., Siegfried, M. R., & Scheidt, C. (2020). Antarctic Topographic Realizations and Geostatistical Modeling Used to Map Subglacial Lakes. Journal of Geophysical Research: Earth Surface, 125(3). (doi:10.1029/2019jf005420)
4. MacKie, E. J., & Schroeder, D. M. (2020). Geostatistically Simulating Subglacial Topography with Synthetic Training Data. IGARSS 2020 - 2020 IEEE International Geoscience and Remote Sensing Symposium. (doi:10.1109/igarss39084.2020.9324563)
5. Culberg, R., Schroeder, D. M., & Chu, W. (2021). Extreme melt season ice layers reduce firn permeability across Greenland. Nature Communications, 12(1). (doi:10.1038/s41467-021-22656-5)
6. Chu, W., Hilger, A. M., Culberg, R., Schroeder, D. M., Jordan, T. M., Seroussi, H., … Vaughan, D. G. (2021). Multisystem Synthesis of Radar Sounding Observations of the Amundsen Sea Sector From the 2004–2005 Field Season. Journal of Geophysical Research: Earth Surface, 126(10). (doi:10.1029/2021jf006296)
7. Schroeder, D. M., Broome, A. L., Conger, A., Lynch, A., Mackie, E. J., & Tarzona, A. (2021). Radiometric analysis of digitized Z-scope records in archival radar sounding film. Journal of Glaciology, 1–8. (doi:10.1017/jog.2021.130)
8. Culberg, R., Schroeder, D. M., & Steinbrügge, G. (2022). Double ridge formation over shallow water sills on Jupiter’s moon Europa. Nature Communications, 13(1). (doi:10.1038/s41467-022-29458-3)
9. Culberg, R., & Schroeder, D. M. (2022). Inverting for Firn Aquifer Properties from Ice-Penetrating Radar Data. IGARSS 2022 - 2022 IEEE International Geoscience and Remote Sensing Symposium. (doi:10.1109/igarss46834.2022.9884947)
10. Culberg, R., Chu, W., & Schroeder, D. M. (2022). Shallow Fracture Buffers High Elevation Runoff in Northwest Greenland. Geophysical Research Letters, 49(23). Portico. (doi:10.1029/2022gl101151)
11. Schroeder, D. M. (2023). Paths forward in radioglaciology. Annals of Glaciology, 1–5. (doi:10.1017/aog.2023.3)