The Impact of Urbanization on Tropical Cyclone Rainfall Over Complex Coastal Terrain

Abstract

Abstract Rapid coastal urbanization alters land–atmosphere interactions and can modify tropical cyclone (TC) rainfall. This study examines urbanization effects on TC rainfall in the Yongjiang River basin, China, using the Weather Research and Forecasting model. Two TCs (Lekima 2019 and In‐fa 2021) with contrasting predominant wind directions are analyzed under historical and future land use scenarios derived from multiple Shared Socioeconomic Pathways–Representative Concentration Pathways. Results show that urbanization enhances TC precipitation downwind of urban areas and in the mountainous region. Urban‐induced warming and increased surface roughness strengthen low‐to mid‐level convergence and ascent, and enhance moisture and equivalent potential temperature. In complex terrain, convergent ascent anomalies can propagate downwind, further amplifying rainfall over the mountainous region. Terrain‐removal experiments further verify the role of topography in the urbanization effect of TC precipitation. These results quantify how urbanization intensifies TC rainfall in coastal regions and highlight the importance of accounting for urban expansion in flood and disaster planning.