Oral

IACS

JCM04 - Recent Advances in Ice Core Science

Two new 150m ice cores and ground geophysics at Canisteo Peninsula, Amundsen Sea, West Antarctica: successful first fieldwork for the Ross-Amundsen Ice Core Array (RAICA) initiative

The Pacific coastline of West Antarctica is changing rapidly?experiencing thinning, mass loss, and retreat of ice shelves critical for stability of the West Antarctic Ice Sheet (WAIS). Despite this observed change due to complex ice-ocean-atmosphere interactions perturbed by combined internal and forced climate processes, there remains a paucity of terrestrial climate records and surface mass balance observations along the ~1900 km-long coastline from Ross Ice Shelf to Pine Island Glacier. Ice rises, regions of grounded ice within ice shelves, are ideal ice core sites and many are located along the WAIS coastline?providing opportunity to reconstruct coastal climate and environmental parameters back decades to millennia at annual resolution. An international team successfully collected 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. 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. 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. 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. Once analyzed, these approximately 150-200 year-long cores will provide baseline proxy observations of fundamental climate variables (temperature, wind, snowfall) which play a poorly-quantified role in forcing Amundsen Sea regional glacier change. They will also expand on the existing inland WAIS ice core array, build on the completed International Thwaites Glacier Collaboration, 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.