Urbanization and Local-scale storm characteristics dominate spatially divergent tropical cyclone rainfall trends in South China

This article examines how urbanization and local-scale storm characteristics shape tropical cyclone rainfall trends in South China, challenging the common assumption that climate warming leads to uniform increases in storm-related precipitation. Drawing on an analysis of 366 tropical cyclones affecting South China between 1979 and 2018, the authors show that rainfall trends are spatially divergent and strongly influenced by processes operating at the 50–150 km scale. 

The study identifies changes in local storm characteristics as key drivers of this divergence. At the 150 km scale, increases in storm duration, intensity, and track density closely match areas with rising rainfall trends. Storms have become longer-lasting, more intense, and more tortuous in their tracks, contributing to higher rainfall accumulation in certain regions. Correlation analysis shows that local-scale duration is the strongest predictor of precipitation trends (R = 0.70), far exceeding relationships at broader regional scales. This demonstrates that local storm dynamics, rather than basin-scale climate signals alone, dominate spatial rainfall outcomes.