Improving the snow physics of WEB-DHM and its point evaluation at the SnowMIP sites

Abstract

Abstract. In this study, the snow physics of a distributed biosphere hydrological model, referred to as the Water and Energy Budget based Distributed Hydrological Model (WEB-DHM) is significantly improved by incorporating the three-layer physically based energy balance snowmelt model of Simplified Simple Biosphere 3 (SSiB3) and the Biosphere-Atmosphere Transfer Scheme (BATS) albedo scheme. WEB-DHM with improved snow physics is hereafter termed WEB-DHM-S. Since the in-situ observations of spatially-distributed snow variables with high resolution are currently not available over large regions, the new distributed system (WEB-DHM-S) is at first rigorously tested with comprehensive point measurements. The stations used for evaluation comprise the four open sites of the Snow Model Intercomparison Project (SnowMIP) phase 1 with different climate characteristics (Col de Porte in France, Weissfluhjoch in Switzerland, Goose Bay in Canada and Sleepers River in USA) and one open/forest site of the SnowMIP phase 2 (Hitsujigaoka in Japan). The comparisons of the snow depth, snow water equivalent, surface temperature, snow albedo and snowmelt runoff at the SnowMIP1 sites reveal that WEB-DHM-S, in general, is capable of simulating the internal snow process better than the original WEB-DHM. Sensitivity tests (through incremental addition of model processes) are performed to illustrate the necessity of improvements over WEB-DHM and indicate that both the 3-layer snow module and the new albedo scheme are essential. The canopy effects on snow processes are studied at the Hitsujigaoka site of the SnowMIP2 showing that the snow holding capacity of the canopy plays a vital role in simulating the snow depth on ground. Through these point evalua-Correspondence to: M. Shrestha (maheswor@hydra.t.u-tokyo.ac.jp) tions and sensitivity studies, WEB-DHM-S has demonstrated the potential to address basin-scale snow processes (e.g., the snowmelt runoff), since it inherits the distributed hydrological framework from the WEB-DHM (e.g., the slope-driven runoff generation with a grid-hillslope scheme, and the flow routing in the river network).

Optimizing Snowfall Correction Factor for Radar-Amedas Precipitation Using Distributed Snow Model (Web-DHM-S) and Modis Snow Cover Data

“…WEB-DHM-S was developed by coupling the three layer snow physics of Simplified Simple Biosphere Model version 3 (SSiB3) 14) and albedo physics of Biosphere-Atmosphere-TransferScheme (BATS) 15) into the WEB-DHM model. The point scale 11,16) and basin scale 12,17) evaluation of WEB-DHM-S at wide regions showed that the model was able to simulate the variability of snow density, snow depth and snow water equivalent, snow albedo, snow layer temperature, snow cover area and runoff. Details of the model equations and snow physics can be found in Shrestha et al 11,12) .…”

“…The point scale 11,16) and basin scale 12,17) evaluation of WEB-DHM-S at wide regions showed that the model was able to simulate the variability of snow density, snow depth and snow water equivalent, snow albedo, snow layer temperature, snow cover area and runoff. Details of the model equations and snow physics can be found in Shrestha et al 11,12) .…”

“…The snowmelt model applied in this study is the WEB-DHM-S (Water and Energy Budget -based Distributed Hydrological Model with improved snow physics) 11,12) . WEB-DHM-S is the improved version of WEB-DHM 13) in its snow physics in the distributed biosphere hydrological modeling framework.…”

The detailed snowpack scheme Crocus and its implementation in SURFEX v7.2

“…A snow scheme of this kind, named ISBAExplicit Snow (ES), is currently implemented in SURFEX, within the ISBA land surface model (Noilhan and Planton, 1989;Boone and Etchevers, 2001), and is used operationally for hydrological applications in Météo-France (Habets et al, 2008). Many intermediate complexity snowpacks schemes exist, such as JULES (Best et al, 2011), CLASS (Brown et al, 2006), the Community Land-surface Model (CLM) (Oleson et al, 2010), WEB-DHM (Shrestha et al, 2010), and Snow 17 (Anderson, 1976). Models of this kind have been recently implemented within NWP and Earth's system models such as HTESSEL (Dutra et al, 2010) and RACMO (Kuipers Munneke et al, 2011).…”

Correcting basin-scale snowfall in a mountainous basin using a distributed snowmelt model and remote-sensing data

“…This approach uses a comprehensive multilayer, energy balance-based snowmelt model, with both water and energy balance closure in a snow-soil-vegetationatmosphere transfer-based distributed biosphere hydrologic modelling framework (WEB-DHM-S; Shrestha et al, 2010Shrestha et al, , 2012a. The method optimises an elevation-dependent correction factor, using a heuristic algorithm called Shuffled Complex Evolution-University of Arizona (SCE-UA; Duan et al, 1992).…”