High-resolution analysis of convective rainfall properties in a tropical city

Urban hydrological systems are highly sensitive to precipitation variability at fine spatial and temporal scales, yet such variability remains poorly characterized due to limited high-resolution observations. Here, we analyze extreme rainfall in equatorial Singapore using a uniquely dense observational network, including 122 rain gauges at 5-min resolution (2020–2024), and long-term hourly gauge records (1980–2024), which are then combined with X-band radar data at 100-m and 5-min resolution to produce a high-resolution gridded rainfall reanalysis. We use this new dataset to quantify the changing space–time organization of extreme convective rainfall over 45 years. Results show that extreme convective rainfall in this tropical urban environment is more highly localized and short-lived than previously thought, with spatial and temporal correlations halving over just 1.6 km and 4 min. In response to climate warming, the total rainfall amount, spatial extent, and temporal persistence of extreme events have increased, while peak rainfall intensities remained largely stable, likely due to limitations in local humidity supply. Such compact storm structures challenge the representativeness of sparse rain gauge networks and underscore the need for high-resolution analysis in tropical regions.