A comparison between two statistical and a physically-based model in snow water equivalent mapping

Snow water equivalent (SWE) estimates at the end of the winter season have been compared for the 2002-2006 period in a 200 km(2) mountainous area in Switzerland, using three different models. The first model, ALPINE3D, is a physically based process-oriented model, which solves the snowpack energy and mass balance equations. The other two models, SWE-SEM and HS-SWE, are statistical algorithms interpolating snow data on a grid. While SWE-SEM interpolates local estimates of SWE, HS-SWE converts interpolated snow depth maps into maps of SWE using a regionally-calibrated conversion model. We discuss similarities and differences among the models' results, both in terms of total volume, and spatial distribution of SWE. The comparison shows a general good agreement of the results of the three models, with a mean difference in the total volumes between the two statistical models of similar to 8%, and between the physical model and the statistical ones of similar to-3% to -10%. (C) 2013 Elsevier Ltd. All rights reserved.