Urbanization exacerbates intensification of short-duration rainfall extremes in a warming climate

Abstract

<p>Intensification of short-duration rainfall extremes is posing greater urban flood risk. Yet, it remains intriguing how the upper-tail statistics update with regional warming. Here, we characterize the non-stationarity of rainfall extremes with durations from 1 to 24 hours over a rapidly developing coastal megalopolis, namely the Greater Bay Area in China, using multi-source merged gridded data of high spatiotemporal resolution. We observe prominent increasing rainfall intensities particularly for the north-central part of the region as opposed to the southern coastal region. Our results show, for the first time, that urbanization nonlinearly exacerbates the rainfall intensities at different extremities, which favors short durations ( 3-hour) and short return periods (2-year), with remarkably high return level-based scaling rates (> 34%/°C). Conversely, rural areas exhibit higher scaling rates than the urban areas for longer durations ( 9-hour), with lower degree of dependency on both durations and return periods.</p>