EGU General Assembly 2023
© Author(s) 2023. This work is distributed under
the Creative Commons Attribution 4.0 License.

Revisiting the impact of anomalous precipitation on the mass budget of the Amundsen Sea Embayment ice streams

Benjamin Davison1, Anna Hogg1, Richard Rigby1, Sanne Veldhuijsen2, Melchior van Wessem2, Michiel van den Broeke2, Paul Holland3, Heather Selley1, and Pierre Dutrieux3
Benjamin Davison et al.
  • 1School of Earth and Environment, University of Leeds, Leeds, UK
  • 2Institute for Marine and Atmospheric Research Utrecht, Utrecht University, the Netherlands
  • 3British Antarctic Survey, Cambridge, UK

Mass loss from the West Antarctic Ice Sheet is dominated by glaciers draining into the Amundsen Sea Embayment (ASE). The majority of that mass loss is driven by decadal variations in submarine melt rates. However, periods of extremely high or low precipitation can compound or mitigate ocean-driven mass losses, yet the impact of anomalous precipitation on the mass balance of the ASE is poorly known. We present a 25-year (1996-2021) record of ASE input-output mass balance and evaluate how two periods of anomalous precipitation affected its sea level contribution. Since 1996, the ASE has lost 3331±424 Gt ice, contributing 9.2±1.2 mm to global sea level. Overall, surface mass balance changes contributed just 7.7 % to total mass loss; however, two anomalous precipitation events had a larger, albeit short-lived, impact on rates of mass change. During 2009-2013, persistently low snowfall, due to anomalously zonal circulation, led to an additional 51±4 Gt yr-1 mass loss in those years (contributing positively to the total loss of 195±4 Gt yr-1). Contrastingly, extreme precipitation in the winters of 2019 and 2020 decreased mass loss by 60±16 Gt yr-1 during those years (contributing negatively to the total loss of 107±15 Gt yr-1). These results demonstrate that extreme snowfall variability can have a substantial impact on the short-term sea level contribution from West Antarctica and show that mass changes do not necessarily scale with grounding line discharge anomalies.

How to cite: Davison, B., Hogg, A., Rigby, R., Veldhuijsen, S., van Wessem, M., van den Broeke, M., Holland, P., Selley, H., and Dutrieux, P.: Revisiting the impact of anomalous precipitation on the mass budget of the Amundsen Sea Embayment ice streams, EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-11661,, 2023.