A Numerical Study on Atmospheric Transport and Diffusion Response to Rapid Urbanization

With a three-dimensional, non-hydrostatic regional boundary layer model of Nanjing University (NJU-RBLM), some numerical experiments are employed to investigate the land-use change impacts on the urban turbulence diffusion. The land-use change of Beijing in 1980, 1990, 2000, 2004 are taken as examples. The simulation results show that land-use change has a great effect on the thermal and dynamical structure of urban boundary layer in the fine, light wind weather condition whenever in summer or winter. The urban land-use change directly impacts the surface energy balance, and also alters the exchange of momentum, heat, and water vapor between ground surface and near surface atmosphere. The turbulence strengthens and the mixture layer depth lifts at the same time, and the materials´ vertical mixture are more sufficient at noon in summer. While for more obvious convergence airflow and stable atmospheric stratification at night in winter, the more many materials and energy are held up in near surface layers atmosphere of urban region.