RINGS (ice sheet margin)

To fill this major knowledge gap across all the margins of Antarctica for the first time, the Antarctic RINGS Action Group will be an ambitious and challenging initiative in a truly international cooperation. The primary goal is to provide more accurate and complete reference bed topography data for robust assessments of ice discharge from all around Antarctica. This dataset will also tremendously improve the accuracy of ice-sheet models by providing a better mapping of the grounding zone. When this dataset is combined with satellite altimetry data over the entire ice sheet, it can also be used to constrain mass input from snowfall to Antarctica, which is currently estimated with regional climate models but hardly validated over a large region. The secondary goals are (1) to better constrain the likelihood and rates of predicted future retreat of the ice-sheet margin by determining basal boundary conditions in adjacent inland areas, (2) to better quantify ice-ocean interactions by providing novel knowledge of the bathymetry of the cavity beneath adjacent ice shelves, and (3) to perceive subglacial hydrology for constraining basal mass balance of the ice sheet and subglacial geology particularly relevant to sediments and heat flow. To reach these objectives, it is necessary to complete not only the primary ring at the margin, but also a seaward ice-shelf ring and a landward ring, using radar, gravity, magnetics and lidar instruments altogether.

The RINGS group will first analyze location data of BedMachine’s input radar data and soon-to-be-available BEDMAP3 open-data depositary. This will lead to the development of a set of protocols followed by future surveys. Available logistical resources and relevant constraints will be considered to examine first-order survey options. This process is interactive and will start with an international workshop, followed up with online meetings of smaller groups. This process also serves as a discussion forum to develop survey plans to balance the primary and secondary objectives of RINGS in the most efficient manner.

There are four milestones M1-M4:

The RINGS Action Group will work for two years to facilitate community efforts to fill critical knowledge gaps in the Antarctic Ice Sheet margins to monitor and predict the future of the Antarctic Ice Sheet. As a SCAR Action Group, RINGS aims to:

• Define knowledge gaps of geophysical datasets in the ice-sheet margins.
• Assess impacts of efforts to fill these knowledge gaps at different levels on estimates of ice discharge from Antarctica and on predicting the future of the ice sheet.
• Develop feasible plans to fill these knowledge gaps by generating interdisciplinary, and international synergies.