Impact of spatial resolution on large-scale ice cover modeling of mountainous regions
- 1GFZ German Research Centre for Geosciences, Potsdam, Germany
- 2Institute of Geographical Sciences, Freie Universität Berlin, Berlin, Germany
- 3PIK Potsdam Institute for Climate Impact Research, Potsdam, Germany
- 4Institute for Physics and Astronomy, University of Potsdam, Potsdam, Germany
- 5Insitute of Earth Surface Dynamics, University of Lausanne, Lausanne, Switzerland
For reconstructing paleoclimate or studying glacial isostatic effects on the Earth’s lithosphere, increasingly more studies focus on modeling the large-scale ice cover in mountainous regions over long time scales. However, balancing model complexity and the spatial extent with computational costs is challenging. Previous studies of large-scale ice cover simulation in mountain areas such as the European Alps, New Zealand, and the Tibetan Plateau, typically used 1-2 km spatial resolution. However, mountains are characterized by high peaks and steep slopes - topographic features that are crucial for glacier mass balance and dynamics, but poorly resolved in coarse resolution topography.
The Instructed Glacier Model (IGM) is a novel 3D ice model equipped with a Convolutional Neural Network which is trained from high order ice models to simulate ice flow. This results in a significant acceleration of run times, and thereby opening the possibility of running in higher spatial resolution. We use IGM to perform simulations of the entire European Alps (covering 480 240 km2), comparing models with 200 m and 2000 m resolution. We apply a linear cooling rate to today’s climate until 6 °C colder to mimic ice age conditions and model the expanding ice cover over a time period of 70,000 years.
Preliminary results indicate systematic, resolution-related differences: At the beginning of cooling, when ice accumulates at high elevations, the lower resolution yields slightly more ice volume. However, this trend reverses after ~ 41,000 years, right before the large valleys are filled with thick ice. When the Alps are fully ice covered, we find up to 15% more ice volume in the higher resolution model. The differences in ice volume are not uniformly distributed in space. The higher resolution model yields thicker and more extensive ice in some regions - mostly large valley systems - of up to 12,000 km2 , and thinner and less extensive ice in other, slightly smaller regions of the Alps. Currently, we analyze to what extent the glacier flow from steep slopes into larger, shallow valleys is represented at the different resolutions.
How to cite: Werner, H., Scherler, D., Winkelmann, R., and Jouvet, G.: Impact of spatial resolution on large-scale ice cover modeling of mountainous regions, EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-4200, https://doi.org/10.5194/egusphere-egu23-4200, 2023.
