Quality Assessment of CMPAS Precipitation Product Data over the Dadu River Basin

Abstract

The Dadu River is the largest tributary of the Minjiang system in the Yangtze River basin. In recent years, frequent storm events in the upper reaches of the Yangtze River have made accurate evaluation of precipitation data in the basin particularly important. The CMPAS (CMA Multi-source Precipitation Analysis System) precipitation product, generated by the National Meteorological Information Center through the fusion of multiple data sources, boasts high spatial and temporal resolution. This study evaluates the accuracy of CMPAS precipitation data at an hourly scale for the Dadu River basin and applies it to the distributed Xinanjiang model to assess the results of hourly runoff simulation. The results show that the spatial distribution of hourly CMPAS precipitation data aligns with isohyets, and the overall accuracy indicators of the data are relatively good. However, the reliability in terms of precipitation identification and hydrological simulation is poor, and the error distribution is uneven. Consequently, while CMPAS precipitation data can serve as a reference for the spatial distribution of precipitation in the Dadu River basin, further calibration is required for its use in hydrological forecasting and other applications.