EGU General Assembly 2022
© Author(s) 2022. This work is distributed under
the Creative Commons Attribution 4.0 License.

Unraveling energy balance partitioning in sub-alpine forests: interplay of canopy structure, topography, and meteorological conditions

Giulia Mazzotti1, Clare Webster1,2, Louis Quéno1, Bertrand Cluzet1, Richard Essery3, and Tobias Jonas1
Giulia Mazzotti et al.
  • 1WSL Institute for Snow and Avalanche Research SLF, Davos, Davos Dorf, Switzerland (
  • 2University of Oslo
  • 3University of Edinburgh

In Alpine regions, forests that overlap with seasonal snow mostly reside in complex terrain. Due to major observational challenges in these environments, the combined impact of forest structure and topography on seasonal snow cover dynamics is still poorly understood. However, recent advances in forest snow process representation and increasing availability of detailed canopy structure datasets now allow for hyper-resolution (<5 m) snow model simulations capable of resolving tree-scale processes. These simulations can shed light on the complex process interactions that govern forest snow cover dynamics.

We present multi-year simulations at 2 m resolution obtained with FSM2, a mass- and energy-balance based forest snow model specifically developed and validated for meter-scale applications. Our 3km2 model domain encompasses forested slopes of a sub-alpine valley in the Eastern Swiss Alps. Simulations thus span a wide range of canopy structures, terrain characteristics, and meteorological conditions typical for the region. We analyze spatial and temporal variations in forest snow energy balance partitioning, aiming to quantify and understand the contribution of individual energy exchange processes at different locations and times.

Our results suggest that snow cover evolution is equally affected by fine-scale canopy structure, terrain characteristics and meteorological conditions. We show that the interaction of these three factors can lead to snow distribution and melt patterns that vary between years. Generally, we find higher snow distribution variability and complexity in slopes that receive solar radiation early in winter. Our process-level insights corroborate and complement existing empirical findings that are largely based on snow distribution datasets only. Hyper-resolution simulations as presented here will thus help us to better understand how ecohydrological regimes sub-alpine regions may evolve as a result of forest disturbances and a warming climate.

How to cite: Mazzotti, G., Webster, C., Quéno, L., Cluzet, B., Essery, R., and Jonas, T.: Unraveling energy balance partitioning in sub-alpine forests: interplay of canopy structure, topography, and meteorological conditions, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-11913,, 2022.