Assessment of uncertainty sources in snow cover simulation in the Tibetan Plateau

State-of-the-art models, however, show significant simulation biases. In this study, we assess the main uncertainty associated with model physics in snow cover modeling over the TP using ground-based observations and high-resolution snow cover satellite products from the Moderate Resolution Imaging Spectroradiometer (MODIS) and FengYun-3B (FY3B).

We first conducted 10-km simulations using the Noah with multiparameterization (Noah-MP) land surface model by optimizing physics-scheme options, which reduces 8.2% absolute bias of annual snow cover fraction (SCF) compared with the default model settings. Then, five SCF parameterizations in Noah-MP were optimized and assessed, with three of them further reducing the annual SCF biases from around 15% to less than 2%. Thus, optimizing SCF parameterizations appears to be more important than optimizing physics-scheme options in reducing the uncertainty of snow modeling.