What is the Trade-Off between Snowpack Stratification and Simulated Snow Water Equivalent in a Physically-Based Snow Model?

Julien Augas,Michel Baraer,Alain N Rousseau,Kian Abbasnezhadi

doi:10.3390/w12123449

Abstract

In Nordic watersheds, estimation of the dynamics of snow water equivalent (SWE) represents a major step toward a satisfactory modeling of the annual hydrograph. For a multilayer, physically-based snow model like MASiN (Modèle Autonome de Simulation de la Neige), the number of modeled snow layers can affect the accuracy of the simulated SWE. The objective of this study was to identify the maximum number of snow layers (MNSL) that would define the trade-off between snowpack stratification and SWE modeling accuracy. Results indicated that decreasing the MNSL reduced the SWE modeling accuracy since the thermal energy balance and the mass balance were less accurately resolved by the model. Nevertheless, from a performance standpoint, SWE modeling can be accurate enough with a MNSL of two (2), with a substantial performance drop for a MNSL value of around nine (9). Additionally, the linear correlation between the values of the calibrated parameters and the MNSL indicated that reducing the latter in MASiN increased the fresh snow density and the settlement coefficient, while the maximum radiation coefficient decreased. In this case, MASiN favored the melting process, and thus the homogenization of snow layers occurred from the top layers of the snowpack in the modeling algorithm.

Highlights

In northern watersheds, snowfall constitutes a significant proportion of the total precipitation [1,2].When rainfall happens at a low rate, water infiltrates until the soil becomes saturated, at which point surface runoff occurs
The results are displayed using boxplots, where the maximum number of snow layers (MNSL) values are shown on the abscissa, and the modeling performances are displayed on the ordinate
As the calibrated parameters directly affect different physical processes, studying their correlations with the MNSL values can provide valuable insights on how MASiN operates under different parameterizations

Summary

Introduction

Snowfall constitutes a significant proportion of the total precipitation [1,2].When rainfall happens at a low rate, water infiltrates until the soil becomes saturated, at which point surface runoff occurs. Snowfall constitutes a significant proportion of the total precipitation [1,2]. When snowfall takes place, water is stored on the ground surface in solid form, modifying the soil water dynamic throughout the watershed [3]. The snowpack starts melting as it absorbs the amount of energy required for phase change to occur. This process can happen partially during winter, the atmospheric warming during spring will gradually melt the entire snowpack. Accumulation and gradual snowmelt processes temporally alter a significant proportion of the total precipitation to flow toward the river network or recharge the groundwater [4,5,6]

Objectives

Methods

Results

Conclusion