Land surface models (LSMs) are an integral part of the Global Climate Models (GCMs) and Earth System Models (ESMs). They play a critical role in increasing our understanding of global climate changes and assess the impacts of anthropogenic activities on those changes. 　　The purpose of this workshop is to bring together land surface modelers from several major land surface modeling research centers to discuss the state of research on uncertainty analysis of land surface models (LSMs), and explore ways to quantify and reduce uncertainties in land surface modeling. The four themes of the workshop are: How do we quantify uncertainties of global land surface models? Parameter sensitivity analysis: why are model outputs are so different? Observations: what trends have we identified in regional and global ET, GPP and GPP/ET and how to use observations to constrain model simulations? Model error analysis: what can we learn from different models to reduce model error?