Assessments of multiple precipitation products and application in hydrodynamic simulations: A case of casualty-inducing mountain torrents in Sichuan, Southwest China

Mountain torrents are frequent and severe hazards, causing serious economic losses and personnel casualties, and in particular, they are the most dangerous threat in the complex terrain. Multi-source precipitation products should be used to drive the hydrological models to improve understanding of the processes of mountain torrents. Fifteen sets of precipitation products are evaluated against the ground observations in situ within a serious mountain torrent caused by a severe rainstorm at June 26, 2020 in Sichuan. The multi-source merged precipitation products performed better than the others. Satellite-based precipitation performed better than model-based products, while IMERG-Early and FY2G performed better than other satellite-based precipitation products. The reanalysis datasets are relatively worse than the observed products. The operational NWPs strongly underestimated precipitation in the mountainous areas. Furthermore, the related floods caused by the rainstorm is simulated based on various precipitation products by a raster-based hydrodynamic two-dimensional model of FloodArea. Most observation-based precipitation products represented the flooding area well, while the model-based precipitation products underestimated the severity of the mountain torrents. Finally, the risk of mountain torrents under variant return-period rainfall is analyzed. The result shows the potential of real-time torrent monitoring and forecasting using high-resolution DEM and precipitation products.