Evaluation of GSMaP and MSWEP precipitation products for runoff simulation in the Lhasa River Basin

As the Asian Water Tower, the Tibetan Plateau (TP) plays a pivotal role in regulating the regional water cycle, yet sparse rain gauge networks hinder reliable hydrological modeling and climate change assessments.This study focuses on the Lhasa River Basin, a representative high-altitude basin in central TP, to evaluate the performance of two satellite-based precipitation products, GSMaP and MSWEP, for runoff simulation using the BTOP distributed hydrological model.Precipitation accuracy was assessed using the critical success index (CSI), correlation coefficient (CC), and coefficient of determination (R 2 ), while hydrological simulations were evaluated through calibration and validation against observed discharge using the Nash-Sutcliffe Efficiency (NSE).The main findings are: (1) GSMaP generally outperforms MSWEP, with an average CSI of 0.8126 compared to 0.7521, ranging from 0.8690 at Lhasa station to 0.7453 at Biruo station; (2) GSMaP shows stronger consistency with observations, with higher CC and R 2 values (R 2 = 0.82 vs. 0.77); (3) both datasets perform well in the wet season (CC > 0.8) but degrade in the dry season, with GSMaP exhibiting smaller time-series errors; and (4) the BTOP model driven by GSMaP achieves higher NSE values in both calibration (0.793) and validation (0.541) periods, more effectively reproducing basin hydrological processes despite some peak flow deviations during flood events.Overall, the results indicate that GSMaP provides more accurate precipitation estimates and runoff simulations in the Lhasa River Basin, offering reliable data support for hydrological research and water resource management in data-scarce regions of the TP.