A case study of urbanization impact on summer precipitation in the Greater Beijing Metropolitan Area: Urban heat island versus aerosol effects

摘要: Convection-resolving ensemble simulations using the WRF-Chem model coupled with a single-layer Urban Canopy Model are conducted to investigate individual and combined impacts of land use anthropogenic pollutant emissions from urbanization on heavy rainfall event in Greater Beijing Metropolitan Area (GBMA) China. The simulation effect included generally captures spatial pattern temporal variation event. An improvement precipitation is found experiment including aerosol both clouds radiation. expanded urban cover increased aerosols have an opposite processes, latter playing more dominant role, leading suppressed convection over upstream (northwest) area, enhanced downstream (southeast) region GBMA. In addition, influence indirect overwhelm that direct this Increased lead cloud droplets smaller size, which favor evaporative cooling reduce updrafts suppress early stage As system propagates southeastward, latent heat released due freezing larger number drops lofted above level, responsible for updraft strength convective invigoration area.