Utility of Open-Access Long-Term Precipitation Data Products for Correcting Climate Model Projection in South China

Insufficient precipitation observations hinder the bias-correction of Global Climate Model (GCM) outputs in ungauged and remote areas. As a result, reliability future water resource projections is restricted for these Open-access quantitative estimation (QPE) products offer potential solution to this challenge. This study assesses effectiveness three widely used, long-term QPEs, including ERA5, PERSIANN-CDR, CHIRPS, bias-correcting from CMIP6 GCMs. The evaluation involves reproduction distribution, streamflow simulation utility based on hydrological model, accuracy extreme indices associated with rainstorm/flood/drought events. selects Beijiang basin located subtropical monsoon area South China as case area. results demonstrate that using QPEs improves performance GCM reproducing precipitation/streamflow distribution indices, few exceptions. PCDR generally exhibits most effective utility, consistently delivering reasonable across various cases, making it suitable alternative gauge data However, corrected by ERA5 tend overestimate overall (by up about 25% 30%), while correction CHIRPS significantly certain 50% 100%). Based revealed correcting outputs, provides references selecting GCM-based