Analysis of error characteristics of Multi-source precipitation products in Hanjiang River Basin

Multi-source precipitation products provide convenient access to large-scale precipitation information, and understanding their error characteristics and applicability is essential for regional water resource planning and management, flood forecasting, and related fields. This study focuses on Hanjiang River Basin and conducts a systematic evaluation for four precipitation products(ERA5, CHIRPS, GPCC, and PERSIANN-CDR) at the daily scale, using a comprehensive quantitative and qualitative accuracy assessment indicator system. Additionally, an error structure decomposition method is employed to analyze error characteristics across different precipitation intensities. The results indicate that: (1) Topography is a key factor influencing the accuracy of multi-source precipitation products. (2) GPCC demonstrates the highest overall accuracy, effectively capturing precipitation trends and spatial distribution in the Han River Basin. ERA5 exhibits significant overall overestimation but performs well in detecting precipitation across all intensity levels. CHIRPS has the lowest accuracy with pronounced misseddetection errors at all precipitation intensities. PERSIANN-CDR shows abnormally prominent false-alarm errors in light precipitation events. (3) The dominant error for all products is the hit errors, with positive (negative) hit errors are particularly significant during extreme light (heavy) precipitation. This study provides valuable reference for precipitation data research in the Han River Basin and offers a solid basis for the selection and application of precipitation data in similar basins.