Abstract
Snow profiles simulated by the numerical model SNOWPACK were compared with the results of snow pit observations. Comparisons were performed for three regions：(1) Nagaoka, a warm and wet snow region, (2) Shinjo, a dry snow region, and (3) Sapporo, a cold snow region. The purpose of this study was to determine the discrepancy between the simulated and observed results and to discuss methods to effectively improve the accuracy. Average values, standard deviations, and weighted centers of snow temperatures, snow densities, grain sizes, and water contents were calculated for observed and simulated snow profiles to perform quantitative comparisons. Furthermore, adjustment of parameterization for albedo was performed using observed data to minimize the discrepancy caused by the albedo in the snow profile. Adjustment of parameterization showed that the albedo should be parameterized to be lower in wet snow regions than in dry snow regions. Simulated snow profiles agreed well with the observed snow profiles. In the analysis of determining the discrepancies, underestimation of heat conduction, densities, and grain size for fresh snow were found. Heterogeneity of water content was also underestimated. Our results indicate that improvement of thermal conductivity and viscosity coefficient for fresh snow and incorporation of the influence of preferential flow are necessary to effectively enhance the accuracy of SNOWPACK.
