Equatorial extreme convective storms are expanding and becoming more persistent

This study leverages the first long-term, sub-kilometer, sub-hourly observational network in equatorial Singapore (730 k⁢m2), with 122 rain gauges reporting 5 min intensities for 2020–2024 and 82 stations with hourly accumulations for 1980–2024, combined with X-band radar (5 min, 100 m) to produce a high-resolution gridded rainfall reanalysis. Extreme rainfall is projected to intensify with climate warming, yet changes in the spatiotemporal structure of extreme-producing storms remain poorly understood in the tropics, as the most convectively active regions of the world are also the most data-scarce.

The findings indicate that extreme rainfall in Singapore is becoming larger and more persistent, with intensification resulting in higher storm rainfall volumes while rainfall peak intensities remain largely unchanged. Furthermore, extreme rainfall storms are strikingly compact, with spatial and temporal correlations halving over just 2 km and 4 min, decaying faster than previously recognized and observed elsewhere. This suggests that analyses based on coarse data sets or single stations may have misrepresented rainfall intensification under warming.