Modelling Spatio-temporal Transformations of Glacial Moulins
Ecole polytechnique fédérale de Lausanne - EPFL
Lay summary
Surface melt-water from glaciers either drains through supra-glacial rivers or enters the ice sheet through moulins, near vertical shafts that descend deep into the glacier, where it forms englacial and subglacial streams. As water accumulates in moulins it increases the water pressure on the glacial bed. If the water pressure on the glacier bed is high enough, bed separation can occur which reduces basal friction and leads to an increased glacial flow.
We study moulins to foresee the influence of increased surface water melting, due to a changing climate, on the flow velocity of the worlds’ glaciers. Particularly in polar regions, where temperatures rise fastest, an increased glacial flow and the associated freshwater discharge can have negative effects on maritime ecosystems.
In traditional models, which aim to predict glacial flow, moulins are modelled as cylindrical vertical tubes. However, moulins have recently been discovered to not only divert as much as 45 degrees from the vertical, but also to have complex geometries which affects their water storing capacity.
To better understand the geometry and temporal changes of moulins, we will lower a novel sensor rig deep into moulins. The onboard instruments allow us to create geotagged maps of a moulin in a common coordinate reference across repeated field trips. These geotagged maps will allow us to draw conclusions on the spatio-temporal evolution of the observed moulins, in particular their water holding capacity. With the acquired data, we aim to enable the development of novel dynamic models for the water holding capacity of moulins throughout the seasons to predict glacial flow more accurately.
Details
| Regional focus | High-altitude |
| Location | Mer de Glace, Chamonix, France |
| Funded amount | 11,000 CHF |
| Project dates | 1st September 2022 – 31st December 2023 |
| Category | Polar Access Fund |
Publications
| Into the ice: Exploration and data capturing in glacial moulins by a tethered robot |