Monitoring the turbulent movements of subglacial water systems

In a groundbreaking study published in the Journal of Proceedings of the National Academy of Sciences, researchers led by Ugo Nanni from Grenoble Alpes University in France have shed light on the intricate relationship between subglacial water flow and glacier movement.

During the 2018 melt season, Nanni and his team recorded seismic noise generated by subglacial water flow beneath the Argentière glacier in the French Alps. Using a dense array of 98 seismic sensors, they were able to map the subglacial water flow system beneath the glacier.

The results revealed a water flow system dominated by multiple subglacial cavities, producing higher water pressure at the glacier's base. This finding is significant as subglacial water flow is known to influence glacier movement, which in turn affects sea level rise.

However, the relationship between subglacial water flow and glacier movement has been unclear due to a lack of observational data. This study provides valuable insights, showing a transition over time to a more efficient channel-like drainage system. This transition led to a slight deceleration of the glacier, suggesting that locations with a more efficient drainage system may be less sensitive to meltwater increases from climate change.

The study's findings could have far-reaching implications. The seismic observation system developed by Nanni and his team could be adapted to other glaciers and ice sheets with significant subglacial water dynamics, such as the Greenland Ice Sheet, Antarctic Ice Sheet, and large valley glaciers in the Alps and Himalayas.

For further information, Ugo Nanni can be contacted at +33 6 43 29 31 41 or via email. The team's innovative approach to studying subglacial water flow could pave the way for a better understanding of how glaciers respond to climate change, ultimately helping us predict and mitigate the impacts of sea level rise.