Global Evaluation of the Wettest Days Contributing to 50% of Annual Precipitation (WD50)

Amid intensifying global warming, precipitation regimes become increasingly concentrated on the wettest days. Yet, there remains limited research at the global scale analyzing how half of the annual precipitation falls predominantly on these days. Therefore, we leveraged five of the most notable satellite precipitation products (SPPs) to map the number of wettest days that account for 50% of annual precipitation (WD50) across all oceans and landmasses. We found substantial differences in WD50 between SPPs and further evaluated their ability to capture spatial patterns accurately. Out of the SPPs studied, data from the Integrated Multi-satellite Retrievals for Global Precipitation Measurement aligned most closely with rain-gauge measurements. This research also revealed substantial variability in WD50 across reference climate regions, shedding new lights onto the global distribution of WD50—a variable particularly relevant for water resources planning as precipitation regimes are projected to become more unevenly distributed in the future.