Evaluation of Various Precipitation Products Using Ground-Based Discharge Observation at the Nujiang River Basin, China

Precipitation observation and prediction is difficult in many high elevation regions due to the complex terrain and the lack of in situ observations for comparison. The Nujiang River (upper and middle Salween River) basin in the Tibetan Plateau is no exception. Because of this shortcoming, we propose the use of gauge-observed discharge time series at the basin outlet (e.g., Jiayuqiao hydrological station) to evaluate the performance of four different precipitation products (e.g., satellite-based products and reanalysis datasets). A physically-based distributed cryosphere hydrological model with coupled snow and frozen soil physics was adopted to transfer the basin-wide gridded precipitation into the basin-outlet discharges. First, we corrected and evaluated the four precipitation products. A correlation relationship was established between each precipitation product and the available (limited) gauge rainfall within different elevation zones, and then used to correct the four precipitation products in the study basin. Secondly, a distributed cryosphere hydrological model was used to simulate the basin-outlet runoff driven by each corrected precipitation product. The results indicated that modern-era retrospective analysis for Research and Applications, version 2 (MERRA2) precipitation has better performance in the upper Nujiang River basin relative to the other precipitation products based on comparisons of observed and simulated runoff.