Benchmark-screened temporal transferability for historical gridded precipitation reconstruction and spatial drought assessment in hyper-arid Kuwait

Study region Kuwait Study focus Long-term drought assessment is difficult in data-sparse regions where only one or a few stations have records long enough for historical validation, while the wider gauge network is shorter. This study develops a benchmark-screened temporal transferability (BSTT) framework for gridded precipitation reconstruction. PERSIANN-CDR was evaluated using the Airport station as the temporal benchmark and shorter stations for local method selection. Candidate bias-correction methods were tested across calibration windows using backward and forward validation and robustness tests. Transferable methods were then evaluated locally, and the selected method was calibrated independently for each native grid cell to reconstruct precipitation. New hydrological insights for the region Conventional forward validation alone was insufficient to establish historical transferability. LOCI showed the strongest temporal transferability, while MVS and QM remained stable across all calibration windows. The reconstructed record revealed spatial and timescale differences in drought behavior using the Standardized Precipitation Index at 3- and 12-month scales. Drought occurred during about 12.3% and 18.1% of months, respectively, with moderate drought dominant at both scales. Longer-timescale droughts were more persistent, more severe, and affected a larger mean area. The 2001–2018 period showed greater long-timescale duration and severity than 1983–2000, while mean intensity changed little. Regional patterns in duration, severity, intensity, and affected area demonstrate the value of BSTT-based reconstruction where long gauge records are spatially limited