Abstract ID: 3.11785 | Accepted as Talk | Talk/Oral | TBA | TBA

The temporary storage of water in the form of snow and ice and its delayed release as melt is a key feature of Alpine hydrological regimes. Rising temperatures are driving drastic changes in the Alpine cryosphere, including shorter snow seasons and accelerating glacier retreat. While these have profound implications on runoff amounts and seasonality in snow- and glacier-fed catchments, quantifying the contribution of snow and glacier melt to streamflow remains challenging. In particular, the trade-off between model complexity and input data availability often leads to the use of rather simple representations of cryospheric processes in hydrological models, which mostly disregard key drivers of snow distribution dynamics.
Here, we explore the application of FSM2trans, a recent fully distributed snow model based on mass and energy balance and including redistribution processes by wind and avalanches, to partially glacierized Alpine catchments. Simulations are, for the first time, evaluated against glaciological datasets, including spatially distributed in-situ measurements of winter accumulation across the glacier surface and point mass balance timeseries reconstructions at selected ablation stakes. This comparison allows detecting accumulation biases and areas with excessive snow transport in the simulations, and serves as the basis for finetuning FSM2trans for applications in high-alpine glacierized terrain. Comparison of FSM2trans simulations with existing, interpolation-based model estimates of glacier accumulation patterns corroborates the added value of process-based snow modelling for characterizing spatiotemporal accumulation dynamics. Enhanced representation of snow accumulation and depletion over glaciers is expected to enable increased spatial and temporal resolution of glacier mass balance estimates, especially where no in-situ measurements are available. As ultimate goal, this effort aims to provide improved surface water inputs from cryospheric components to hydrological models, thereby allowing for a better characterization of snow and glacier contributions to runoff in mountain catchments.