Hysteretic dynamics of seasonal snow depth distribution in the Swiss Alps

Abstract

The dynamics of the spatial snow distribution is a key feature when investigating a seasonal snow cover on the catchment scale. This study explores the spatial variability of snow depth during the course of snow accumulation and depletion, based on daily data from 77 weather stations in the Swiss Alps during 6 consecutive seasons. We derive a statistical description of the snow cover dynamics by analyzing temporal trajectories in plots of the standard deviation σ() over mean , where xi is a set of snow depth measurements on one particular day. The analysis reveals that the evolution of σ() closely follows a power law σ() = 0.84±0.01 during the accumulation period for all 6 winters. However, during snowmelt, the trajectory of σ() displays a clearly different path as with classical hysteresis phenomena. Surprisingly, a simplistic model of uniform melting describes this path reasonably well. We believe that the conceptual framework outlined in this study is helpful in describing important characteristics of the dynamics of seasonal snow depth spatial variability. Future studies could apply the methodology introduced here to incorporate stochastic means in modeling snow distribution, even for a broader range of length scales and different alpine terrain.