Numerical Simulation of Atmospheric Pollution over Kanto area using the MM5/CMAQ Model 'Simulation of ozone concentration between two different climatic days'

摘要

It is known that in summer, Ozone (O{sub}3) concentration in urban areas can be strongly affected by local climatic condition in which some factors play an important role such as precipitation, cloud, fog especially urban heat island (UHI). In this study, we use the MM5/CMAQ model to investigate influence of climatic change on the atmospheric pollution over Kanto area with two case studies; (1) simulation period with mild weather, and (2) the period that it's hot and clear weather pattern associated with climatic change. The 3 domains, which cover a region of Kanto with grid resolutions of 9 km, 3 km, and 1 km respectively, have been employed for this study. Numerical simulation results showed that: (1) Atmospheric pollution was strongly effected by urban heat island event; (2) the high temperature and weak wind speed lead to significantly increase O{sub}3 concentration; (3) simulated O{sub}3 temporal trends showed good agreement with observation. On the hot day the model overestimated the ozone concentrations after 15:00 pm. One reason may relate to calculating of the vertical diffusion coefficient in the MM5 model. This will be investigated in the next work.