- 1Department of Hydraulic Engineering, Tongji University, Shanghai, China
- 2Institute of Earth Surface Dynamics, University of Lausanne, Switzerland
- 3Expertise Center for Climate Extremes (ECCE), Faculty of Business and Economics (HEC) - Faculty of Geosciences and Environment, University of Lausanne, Switzerland
Tropical cyclones, also known as typhoons in the western North Pacific, are one of the most devastating natural disasters in the world, especially when they strike highly urbanized regions with large populations. For instance, in September 2024, two typhoons, Bebinca and Pulasan, directly affected Shanghai within 4 days, resulting in severe floods, widespread power outages, and the evacuation of more than 500,000 residents. However, there is limited knowledge about the variability and mechanism of typhoon activities in this region under the effect of climate change and urbanization. In light of these facts, we use the Weather Research and Forecasting (WRF) convection-permitting model to simulate five typhoon events that made landfall along the southeastern coast of China and severely impacted Shanghai between 2018 and 2022. By comparing with various scenarios, including the current and projected expansion of Shanghai's urban area and the 1, 2, and 3 °C rise in sea surface temperature (SST), the effects of urbanization and climate change are estimated. The results find that typhoon tracks are significantly shifted southerly away from the city by higher SST, but the typhoon risk continues to increase due to substantial enhancement of rainfall intensity and wind velocity. Warmer SST increases air temperature and decreases sea level pressure, thereby facilitating the formation and development of typhoon sizes and their dynamic systems. The southward shift of the typhoon tracks is linked to the Fujiwhara effect when two typhoons exist and interact, causing an intensified mutual counterclockwise rotation with SST increase. Urbanization further intensifies the local rainfall intensity within Shanghai due to the increase in urban surface roughness. In the future, the risk of typhoons under the compound effects of urbanization and climate warming in Shanghai and other megacities in typhoon-affected regions should be raised to attention.
How to cite: Zhuang, Q., Koukoula, M., Liu, S., Zhou, Z., and Peleg, N.: Increasing typhoon risks in Shanghai under the effect of urbanization and sea surface temperature warming, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-1794, https://doi.org/10.5194/egusphere-egu25-1794, 2025.
