Effects of Urban Expansion and Anthropogenic Heat Enhancement on Tropical Cyclone Precipitation in the Greater Bay Area of China

Abstract

AbstractThe impact of urban expansion and anthropogenic heat (AH) enhancement on tropical cyclone precipitation (TCP) in the Guangdong–Hong Kong–Macau Greater Bay Area (GBA) of China is investigated by using the Weather Research and Forecasting (WRF) model. Sensitivity experiments are conducted during the landfall periods of two tropical cyclones, Hato (2017) and Mangkhut (2018), by artificially varying the surface AH flux from 0 to 600 W/m2 and the urban land surface from 1985 to 2017, respectively. Results show that the TCP in the GBA's urban region increases with both urban expansion and AH enhancement. However, in the urban downstream region, only AH enhancement causes an increase in TCP, whereas urban expansion has no significant influence on TCP. AH enhancement and urban expansion affect surface temperature, surface sensible heat flux, and surface latent heat flux, leading to changes in atmospheric instability and surface water evaporation, resulting in changes in low‐level moisture convergence. The change patterns of the vertically integrated moisture flux divergence between 850 and 910 hPa in the urban and urban downstream regions of the GBA are consistent with those of the TCP changes in this area, indicating that low‐level moisture convergence is the key factor determining the TCP changes in the region.