CFD study on urban climate in Tokyo — Effects of urbanisation on climatic change

The results of CFD analyses of mesoscale climate in the Tokyo area are presented. The model for geophysical flow problems developed by Mellor and Yamada is used for turbulence closure. The accuracy of CFD analysis is examined by comparing its results with the measured data. The topography and present land-use situation in Japan are incorporated into the predictions with the numerical database provided by the National Land Agency of Japan. First, influence of grid resolution and treatment of artificial heat release on predicted results is investigated. The numerical method is then revised to improve prediction accuracy. Furthermore, the urban climate in the end of the Japanese Medieval Period (“Tempo period in Tokugawa Dynasty”: 1830–1844) is also analyzed. By comparing the results of this analysis with those for the case of present situation, the effects of urbanization on the heat island in the Tokyo area are clarified.