USAP-DC

Recent observations and model results suggest that collapse of the Amundsen Sea sector of West Antarctica may already be underway. However, the timeline of collapse and the effects of ongoing climatic and oceanographic changes are key unanswered questions. Complete disintegration of the ice sheet would raise global sea level by more than 3 m, which would have significant societal impacts. Improved understanding of the controls on ice-sheet evolution is needed to make better predictions of ice-sheet behavior. Results from numerical models show that buttressing from surrounding ice shelves and/or from small-scale grounded ice rises should act to slow the retreat and discharge of ice from the interior ice sheet. However, there are very few field observations with which to develop and validate models. Field observations conducted in the early 1980s on Crary Ice Rise in the Ross Sea Embayment are a notable exception. This project will revisit Crary Ice Rise with new tools to make a suite of measurements designed to address questions about how the ice rise affects ice discharge from the Ross Sea sector of West Antarctica. The team will include a graduate and undergraduate student, and will participate in a range of outreach activities.

New tools including radar, seismic, and GPS instruments will be used to conduct targeted geophysical measurements both on Crary Ice Rise and across its grounding line. The project will use these new measurements, together with available ancillary data to inform a numerical model of grounding line dynamics. The model and measurements will be used to address the (1) How has the ice rise evolved over timescales ranging from: the past few decades; the past millennia after freeze-on; and through the deglaciation? (2) What history of ice dynamics is preserved in the radar-detected internal stratigraphy? (3) What dynamical effect does the presence/absence of the ice rise have on discharge of the Ross Ice Streams today? (4) How is it contributing to the slow-down of the proximal Whillans and Mercer ice streams? (5) What dynamical response will the ice rise have under future environmental change?

Person	Role
Conway, Howard	Investigator and contact
Koutnik, Michelle	Co-Investigator
Winberry, Paul	Co-Investigator
Martin, Carlos	Researcher
Hillebrand, Trevor	Researcher

Antarctic Glaciology	Award # 1443552
Antarctic Glaciology	Award # 1443356

USAP-1443356_1

None in the Database

Repository	Title (link)	Format(s)	Status
USAP-DC	Geophysical data from Crary Ice Rise, Ross Sea Embayment	None	exists
CReSIS/ku.edu	2015_Antarctica_Ground	None	exist

1. Martín, C, TR Hillebrand, H Conway, JP Winberry, MR Koutnik, HFJ Corr, KW Nicholls, CL Stewart, J Kingslake and A Brisbourne (2017). Radar polarimetry at Crary Ice Rise, Antarctica, reveals details of ice-flow reorganization over the last millennium. European Geophysical Union Meeting, 2017. Vienna, Austria.
2. Hillebrand, T.R., H. Conway, C. Martín, M.R. Koutnik, J.P. Winberry and J. Paden (2016). Structure of Crary Ice Rise, Antarctica revealed by ultra-high frequency radio echo sounding. WAIS2016 Workshop, Sterling, VA.
3. Conway, H., T.R. Hillebrand, J.P. Winberry, C. Martin, M.R. Koutnik and R. Hindmarsh (2017). Crary Ice Rise Revisited. WAIS2017 Workshop. Coupville, Whidby Island, WA.
4. Winberry, J.P., H. Conway, M.R. Koutnik, and C. Martin (2017). Geologic Controls and Ongoing Evolution of the Crary Ice Rise. WAIS2017 Workshop. Coupville, Whidby Island, WA.
5. Hillebrand, T.R., H. Conway, M. Koutnik, C. Mart\u00edn, J. Paden and J.P. Winberry (2021). Radio-echo sounding and waveform modeling reveal abundant marine ice in former rifts and basal crevasses within Crary Ice Rise, Antarctica. J. Glaciology, 1-12. (doi:10.1017/jog.2021.17)
6. Patterson, M. O., Levy, R. H., Kulhanek, D. K., van de Flierdt, T., Horgan, H., Dunbar, G. B., Naish, T. R., Ash, J., Pyne, A., Mandeno, D., Winberry, P., Harwood, D. M., Florindo, F., Jimenez-Espejo, F. J., Läufer, A., Yoo, K.-C., Seki, O., Stocchi, P., … Klages, J. P. (2022). Sensitivity of the West Antarctic Ice Sheet to +2 °C (SWAIS 2C). Scientific Drilling, 30, 101–112. https://doi.org/10.5194/sd-30-101-2022 (doi:10.5194/sd-30-101-2022)