ALPINE3D: a detailed model of mountain surface processes and its application to snow hydrology

Abstract

Abstract:Current models of snow cover distribution, soil moisture, surface runoff and river discharge typically have very simple parameterizations of surface processes, such as degree-day factors or single-layer snow cover representation. For the purpose of reproducing catchment runoff, simple snowmelt routines have proven to be accurate, provided that they are carefully calibrated specifically for the catchment they are applied to. The use of more detailed models is, however, useful to understand and quantify the role of individual surface processes for catchment hydrology, snow cover status and soil moisture distribution.We introduce ALPINE3D, a model for the high-resolution simulation of alpine surface processes, in particular snow processes. The model can be driven by measurements from automatic weather stations or by meteorological model outputs. As a preprocessing alternative, specific high-resolution meteorological fields can be created by running a meteorological model. The core three-dimensional ALPINE3D modules consist of a radiation balance model (which uses a view-factor approach and includes shortwave scattering and longwave emission from terrain and tall vegetation) and a drifting snow model solving a diffusion equation for suspended snow and a saltation transport equation. The processes in the atmosphere are thus treated in three dimensions and are coupled to a distributed (in the hydrological sense of having a spatial representation of the catchment properties) one-dimensional model of vegetation, snow and soil (SNOWPACK) using the assumption that lateral exchange is small in these media. The model is completed by a conceptual runoff module. The model can be run with a choice of modules, thus generating more or less detailed surface forcing data as input for runoff generation simulations. The model modules can be run in a parallel (distributed) mode using a GRID infrastructure to allow computationally demanding tasks. In a case study from the Dischma Valley in eastern Switzerland, we demonstrate that the model is able to simulate snow distribution as seen from a NOAA advanced very high-resolution radiometer image. We then analyse the sensitivity of simulated snow cover distribution and catchment runoff to the use of different surface process descriptions. We compare model runoff simulations with runoff data from 10 consecutive years. The quantitative analysis shows that terrain influence on the radiation processes has a significant influence on catchment hydrology dynamics. Neglecting the role of vegetation and the spatial variability of the soil, on the other hand, had a much smaller influence on the runoff generation dynamics. We conclude that ALPINE3D is a valuable tool to investigate surface dynamics in mountains. It is currently used to investigate snow cover dynamics for avalanche warning and permafrost development and vegetation changes under climate change scenarios. It could also serve to test the output of simpler soil-vegetation-atmosphere transfer schemes used in larger scale climate o...

Hysteretic dynamics of seasonal snow depth distribution in the Swiss Alps

“…A main objective of snow-hydrological modeling is to estimate the total amount of snow water equivalent (SWE) and to predict the snow melt water run-off originating from the snow. There exists a large range of snow model types, from physical deterministic spatial distributed models [e.g., Lehning et al, 2006;Liston and Elder, 2006] and lumped snowmelt models including the concept of the areal depletion curve [Luce et al, 1999] to pure statistical models using sums of correlated gamma distributed variables [Skaugen, 2007].…”

Fine‐scale modeling of the boundary layer wind field over steep topography

“…[10] In a companion study, the wind fields computed with the ARPS model are used to drive the three-dimensional model of Alpine surface and snow drift processes, ALPINE3D [Lehning et al, 2006]. Detailed results of the snow drift modeling with ALPINE3D are presented in a companion paper by Lehning et al [2008].…”

Local and regional variability in snow conditions in northern Finland: A reindeer herding perspective

“…SNOWPACK is a physically based, energy balance model simulating the temporal evolution of the snow Lehning et al (1998) and Rasmus et al (2007). A canopy sub-model (Lehning et al 2006) simulates the impact of vegetation on the upper boundary conditions of the underlying snow cover and models snow depth and structure below forest canopies. The reliability of the sub-model in simulating the radiation transmission through the canopies and snow interception and subsequent effect of these on forest snow mass and energy balance has been validated by Stähli et al (2009) and Musselman et al (2012).…”