Extreme Precipitation Trend in Multiple Urban Systems

Cities are increasingly vulnerable to the effects of flooding due to changes in heavy precipitation patterns as a result of climate warming and rapid urbanization. Under the support of the NASA Interdisciplinary Research in Earth Science Program, we undertake coordinated research activities to explore the impact of urban physical processes on extreme precipitation, especially sub-daily extremes, in multiple urban areas (Tokyo, Singapore, Lagos, Houston, etc.) These research activities were performed by integrating remote-sensing and in-situ observations and high-resolution long-term convection-permitting WRF-urban simulations to tease out the relationship between extreme precipitation evolution and larger-scale climate warming and regional urbanization. We will present and discuss the research approach and main scientific findings. For instance, the study focusing on the Tokyo and Singapore pointed out enhanced hourly extreme precipitation by global-warming. The extreme part of heavy precipitation intensifies, and its intensification rate is at a super Clausius-Clapeyron rate. This has important implications to urban flooding prevention and mitigation and to urban planners, because the precipitation response to future climate warming is not linear, and skewed toward more increased extremes. As a team, we also conduct a coordinated study of the impact of urbanization over the Lagos, Nigeria, region, and examine the evolution of urban heat islands and precipitation as a result of Lagos rapid urbanization in the last two decades. To translate scientific findings into actionable science, we initiated dialogues with university groups in different cities to discuss possible pathways for sharing data and connecting with local stakeholders. Those activities are with the general goal of the World Climate Research Programme (WCRP) My Climate Risk (MCR) initiative. One proposed idea is to establish MCR Regional Urban Hubs to address various urban climate risks.