Hydroclimate assessment of gridded precipitation products for the Tibetan Plateau

Precipitation is the main water source shaping the Tibetan Plateau (TP) to be the Asian "water tower," but it is challenging to estimate. It is crucial to assess the performances of the increasingly available precipitation products for hydroclimate research on the TP. In this paper, three precipitation products (CMFD, TRMM and CHIRPS) are evaluated within a comprehensive framework, covering temporal and spatial consistency between the products, the errors of each product on the basis of extended triple collocation (ETC) analysis, and the performance of each product in reproducing streamflow when used as input in a hydrological model. The results show that, overall, the three products have better precipitation estimates in the southeast of the TP (a wetter region) than in the northwest (a drier region). CMFD and TRMM are more consistent with each other and represent precipitation across the TP better than CHIRPS. Among the three products, the areal precipitation from CMFD results in more satisfactory simulation of streamflow. Collectively, these precipitation products, together with the limited available gauge observations, address the uncertainty range of the predicted streamflow well.