NSF-NERC: Ground Geophysics Survey of Thwaites Glacier
This project contributes to the joint initiative launched by the U.S. National Science Foundation (NSF) and the U.K. Natural Environment Research Council (NERC) to substantially improve decadal and longer-term projections of ice loss and sea-level rise originating from Thwaites Glacier in West Antarctica. The objectives of the project are to learn whether basal conditions allow for rapid retreat of the Thwaites Glacier grounding line or whether retreat may re-stabilize near its current grounding line. These objectives will be achieved by using dedicated ice-flow modeling to guide targeted field surveys and experiments over two seasons, and to measure the most important unknown quantities and incorporate them into the models. Numerical models will be used to generate hypotheses for basal conditions that are testable through geophysical surveys and to project future behavior of Thwaites Glacier after assimilating the resulting data. The geophysical methods include seismic, radar, gravity, and electrical surveys that together will allow for a fuller characterization of the bed. The project will conduct field surveys in areas representative of different parts of the glacier, including across the margins, near the grounding line, and along the central axis of the glacier into its catchment. The Rapid Air Movement (RAM) Drill and Small Hot Water Drill will be used to create the shot holes required for the seismic measurements.
- Point of Contact:
Sridhar Anandakrishnan, Penn State University. Leigh Stearns, University of Kansas. Richard Alley, Penn State University. Knut Christianson, University of Washington. Lucas Zoet, University of Wisconsin
- Schedule: 11/15/2023 - 01/15/2024 (estimated)
- Equipment: Rapid Air Movement (RAM) Drill, Small Hot Water Drill
Center for OLDest Ice Exploration (COLDEX)
Cores drilled through the Antarctic ice sheet provide a remarkable window on the evolution of Earth’s climate and unique samples of the ancient atmosphere. The clear link between greenhouse gases and climate revealed by ice cores underpins much of the scientific understanding of climate change. Unfortunately, the existing data do not extend far enough back in time to reveal key features of climates warmer than today. COLDEX, the Center for Oldest Ice Exploration, will solve this problem by exploring Antarctica for sites to collect the oldest possible record of past climate recorded in the ice sheet.
This component of COLDEX will recover a suite of shallow (16 x < 200 m) ice cores from the Allan Hills and other Antarctic Blue Ice Areas (BIAs) that contribute towards our understanding of how Earth's climate system operated during warmer periods in the past and why the periodicity of glacial cycles lengthened from 40,000 to 100,000 years approximately 1 million years ago. These ice cores will be dated using a newly developed array of dating methods to establish a preliminary depth/age time scale. Subsections of the cores will be imaged and analyzed for stratigraphic orientation using ECM and a suite paleoclimate properties (e.g. CO2, CH4, O2/N2/Ar, water isotopes, etc.).
Sea-ice Snow Microbial Communities' Impact on Antarctic Bromocarbon Budgets and Processes
The ozone hole that develops over the Antarctic continent every spring is attributed to human activity, particularly the production of CFCs (chlorofluorocarbons in refrigerants) released into the atmosphere. Despite the 1987 Montreal Protocol ban on CFCs, the ozone hole's recovery has been slower than predicted. Bromocarbons, known to produce stratospheric ozone depletion, have recently been estimated to contribute to the pool of bromines in the lower atmosphere. This project will test if bromocarbons in sea ice are produced and degraded by microalgae and bacteria found in sea ice, snow, and the interface between the two. Using a Kovacs hand auger, the researchers will drill several cores (up to ~16) through ~1.5 meters of sea ice twice a week for six weeks. The cores will be used to collect chemical and biological measurements of sea ice and snow to determine bromocarbon concentrations, microbial activity associated with them, and intra-cellular genes and proteins involved in bromocarbon metabolism.
RAPID: US-Korean collaboration to build a Ross-Amundsen Ice Core Array (RAICA) along the West Antarctic coastline
Using the Foro 400 Drill, this project aims to recover a 100-150 m long ice core from an ice rise in the Amundsen Sea region of coastal West Antarctica. The ice core will be used to reconstruct annual climate and environmental variability over the past 200-400 years, constrain surface mass balance variability and trends over the (pre)instrumental period, and contribute greater temporal perspective to ongoing investigations of Thwaites Glacier – an extensive system that will contribute significantly to global sea level rise for centuries to come. This project collaborates with Korean Polar Research Institute (KOPRI) scientists and is supported via the KOPRI icebreaker RV ARAON. Martin Peninsula, between the Getz Ice Shelf and the Dotson Ice Shelf, has been chosen as the primary site based on existing airborne snow radar data and the high snow accumulation rate, which preserves high-resolution paleoclimate information. The specific drill site will be chosen based on scientific value and logistical constraints associated with the RV ARAON cruise.