West Antarctic Ice Rises

Motivation: The West Antarctic coastline is changing rapidly: it is thinning, losing mass, and buttressing ice shelves that are critical for future stability of the ice sheet are retreating. Despite observed change caused by ice-ocean-atmosphere interactions perturbed by both internal and forced climate processes (e.g., tropical Pacific Ocean variability, ozone depletion, greenhouse gas warming), there are few direct measurements along this coastline. Ice rises, which are regions of grounded ice within ice shelves, are ideal ice-core sites. Ice rises line this region, allowing for reconstruction of coastal climate and environmental parameters dating back decades to millennia at annual resolution. Retrieval of a 150-m-long ice core from an ice rise in this region will expand our understanding of critical processes relevant to observed coastal change over a timespan of several centuries. Shallower cores also collected on the ice rise, flanking the central 150-m core, will validate the amount and spatial variability of surface change across this ice rise, providing constraint for airborne observations, satellite observations, climate models, and reanalysis datasets. The project forms a new collaboration between a U.S. researcher and the South Korean Polar Research Institute (KOPRI), who will provide the bulk of the logistics, including the use of their research vessel, RV ARAON. 

Results: The international RAICA team deployed on the RV ARAON from December 2023 to February 2024. Supported by the South Korean icebreaker RV ARAON and two AS-350 helicopters, the camp of 8 people spent 13 days at the site in mid-January 2024. The team successfully drilled two 150 meter long ice cores on either side of the ice divide of Canisteo Peninsula ice rise, 130 km north of Pine Island Glacier. One core was collected 500 meters northeast of the Canisteo Peninsula ice divide, using the US IDP Foro 400 drill; a matching core was collected 500 meters southwest of the divide, using a Japanese-manufactured KOPRI ice coring drill. Additionally, 280 km of radar lines were traversed by two snow mobiles, observing ice thickness, internal structure, and shallow surface mass balance variability. ApRES was conducted at one ice core site. 

Future: Once analyzed, these approximately 200 year-long cores will provide baseline proxy observations of fundamental climate variables (temperature, wind, snowfall), extremes, and trends, which play a poorly-quantified role in forcing regional glacier change. They will also expand on the existing inland WAIS ice core array, build on both countries’ ongoing contributions to the International Thwaites Glacier Project, and—with the recovery of additional cores—eventually connect to Korean and other international ice coring efforts in the Ross Sea and Victoria Land regions.