Comparative Analyses of Physically Based Snowmelt Models for Climate Simulations

• DOI: 10.1175/1520-0442(1999)012<2643:caopbs>2.0.co;2
• Publication Date: 2002-07-27T12:27:51Z
• Authors: J. Jin; X. Gao; Z.-L. Yang; R. C. Bales; S. Sorooshian; R. E. Dickinson; S. F. Sun; G. X. Wu
• Keywords: Snowpack; Snowmelt; Meltwater; Energy budget; Liquid water content; Forcing (mathematics)

A comparative study of three snow models with different complexities was carried out to assess how a physically detailed model can improve modeling within general circulation models. The were (a) the U.S. Army Cold Regions Research and Engineering Laboratory Model (SNTHERM), which uses mixture theory simulate multiphase water energy transfer processes in layers; (b) simplified three-layer model, Snow–Atmosphere–Soil Transfer (SAST), includes only ice liquid-water phases;and (c) submodel Biosphere–Atmosphere Scheme (BATS), calculates snowmelt from budget temperature by force–restore method. Given same initial conditions forcing atmosphere radiation, these simulated time series equivalent, surface temperature, fluxes very well, SNTHERM giving best match observations SAST simulation being close. BATS captured major upper portion snowpack where solar radiation provides main source gave satisfying results for seasonal periods. Some biases occurred exchange due its neglecting liquid underestimating density. Ice heat conduction, meltwater transport, melt–freeze process exhibit strong diurnal variations large gradients at uppermost layers snowpacks. Using two 20 cm one deeper layer bottom processes, closely approximated performance computational requirements comparable those BATS.