EGU General Assembly 2022
© Author(s) 2022. This work is distributed under
the Creative Commons Attribution 4.0 License.

A high-accuracy Total Air Content setup: System performance and first results from Skytrain Ice Rise, Antarctica

Christoph Nehrbass-Ahles1, Amy King2, Helene Hoffmann1, Mackenzie Grieman1,3, Isobel Rowell1, Jack Humby2, Shaun Miller2, Elizabeth Thomas2, Thomas Bauska2, Jochen Schmitt4, Robert Mulvaney2, and Eric Wolff1
Christoph Nehrbass-Ahles et al.
  • 1Department of Earth Sciences, University of Cambridge, Cambridge, UK (
  • 2British Antarctic Survey, Cambridge, UK
  • 3Reed College, Portland, Oregon, USA
  • 4Climate and Environmental Physics, Physics Institute, and Oeschger Centre for Climate Change, University of Bern, Switzerland

Some modelling studies and sea level reconstructions suggest the loss of the West Antarctic Ice Sheet (WAIS) during the Last Interglacial (LIG) about ~120’000 ago, but direct evidence for a collapse of the WAIS is lacking. The WArm Climate Stability of the West Antarctic ice sheet in the last INterglacial (WACSWAIN) project aims at providing direct evidence allowing for a comprehensive assessment of whether or not the WAIS collapsed during the LIG. One of the expected consequences of such massive ice mass loss is the change of the elevation of land masses in close proximity of the WAIS due to isostatic adjustments. This process, together with changes in ice sheet thickness, may have altered the elevation of Skytrain Ice Rise above sea level on the order of 200 m. Such major changes in the elevation should be imprinted in the Total Air Content (TAC) based on simple barometric considerations. Here we present a new experimental setup of a high-accuracy, high-precision TAC measurement system constructed at the British Antarctic Survey. This setup is dedicated to and optimised for the measurement of TAC and is based on a vacuum extraction principle. The air is extracted from the ice by melting the sample by thermal radiation and the released air is dried and directly expanded into a 30-litre expansion chamber. State-of-the-art pressure gauges and thorough temperature control allow for an accuracy of 0.2% with a real ice reproducibility of 0.2% to 0.4% for 100 g and 30 g samples, respectively. Here, we discuss the performance of this new TAC system and present first TAC data from the Holocene section of the Skytrain Ice Core, Antarctica.

How to cite: Nehrbass-Ahles, C., King, A., Hoffmann, H., Grieman, M., Rowell, I., Humby, J., Miller, S., Thomas, E., Bauska, T., Schmitt, J., Mulvaney, R., and Wolff, E.: A high-accuracy Total Air Content setup: System performance and first results from Skytrain Ice Rise, Antarctica, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-9210,, 2022.