Precipitation is not only a key variable in climate studies, but also a crucial forcing factor of the hydrological cycle (Do et al., 2020;Jiang & Bauer-Gottwein, 2019;Yao et al., 2020). Currently, various precipitation products are developed through different technologies, such as gauge interpolation, radar observation, satellite retrieval, and assimilation reanalysis (Foufoula-Georgiou et al., 2020;Sun et al., 2018). However, despite the significant advances of these products, there still exists errors associated with them due to many factors (e.g., algorithms, data sources, bias correction). Therefore, it is important to identify and quantify these error sources before proceeding to applications, which is also beneficial to the iterative updates of products (Alijanian et al., 2019;Sorooshian et al., 2000).Many efforts have been done to address this task, including the comparison of gauge observations, intercomparison, and hydrological validation (