Improved snow cover model in terrestrial ecosystem models over the Qinghai-Tibetan Plateau

Snow cover is an important land surface variable, especially in the Qinghai-Tibetan Plateau, and profoundly impacts plant phenology, growth, soil respiration and net ecosystem production. However, few studies have been conducted to examine the reliability of current snow cover models in the Qinghai-Tibetan Plateau. This study examined three snow cover models (SnowMAUS, revised SnowMAUS, and SnowFrostIce) across 23 meteorological stations covering a variety of altitudes. All three models substantially overestimated snow cover depth and numbers of days with snow cover because they ignored the impact of wind speed. Based on SnowMAUS, this study has incorporated equations dealing with wind speed impacts to develop a new model (SnowWind). Moreover, the parameter inversion method was improved by separating snow cover calculations into two processes (snow accumulation and melting) and estimating the parameters of the two processes separately. The results showed that SnowWind can estimate snow cover dynamics with reasonable precision of snow cover presence or absence and, to a large extent, snow cover depth. The better inversion method also improved the number of constrained parameters and model performance. Regional estimates of snow cover are comparable with those derived from satellite-based snow cover products with regard to snow cover days. This result shows the SnowWind model is an alternative approach that makes it possible to simulate sow cover and depth over large areas.