Développement d'un modèle numérique d'évolution du couvert neigeux adapté à la modélisation hydrologique

Abstract

Most hydrological models simulate snowmelt using a degree day or simplified energy balance method which usually requires a calibration of the snow related parameters using discharge data. Despite its apparent efficiency, this method is recognized as promoting equifinalities in models having a large number of parameters and leads to empirical relations which are not proven to remain valid in a changing climate. The objective of this study is to develop a physically based snowpack model suitable for hydrological modeling and whose simulation process would ultimately not require calibration against discharge data. The model called MASiN computes the energy and mass balance of multiple layers of the snowpack using commonly measured meteorological parameters at hourly time step (air temperature, relative humidity, wind velocity) and daily time step (precipitation). Model parameterization is performed at a single site selected among 23 study sites in Canada and Sweden on which the model is tested at. The snow depth simulated by MASiN with a unique set of parameters is compared against measurements and simulations from three other models which were calibrated on the 23 study sites. Models used for comparison are the snow module of the hydrological model Hydrotel and two empirical snow models. On average, MASiN shows the best performance among the four models for two of the three criteria used for comparison. MASiN exhibits lower performances at the northernmost sites. MASiN globaly shows strong time and space transferability which make it a robust snow model for distributed modeling applications in snow cover related studies, particularly when the recourse to calibration is questionned. The application of MASiN to hydrological modeling has only been scratched in this study. The approach used in this first attempt did not bring the expected results regarding discharge simulation performance assessed on four watershed from southern Quebec. However, the results of this first try are presented here.

Date	6 Jun 2016
Original language	French
Awarding Institution	École de technologie supérieure
Supervisor	Michel Baraër (Supervisor)