Heat Island due to the Increasing of Height and Number-density of Buildings in the Big City, and the Relaxation Effect of Green

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The fundamental thermodynamic characteristics over the urban canopy and the rural surface are determined from the albedo, the Stanton number and the value of heating inertia defined by c ρ λ where : c is the effective heat capacity, ρ is the effective density and λ is the effective heat conductivity of the canopy layer. These values are determined from the height, number density and the gross coverage ratio of the buildings (Hizuka and Yasuda, 2005). With these values and the non-hydrodynamic simulation model developed by Sha, the sea-breeze over the Miyagi Prefecture including Sendai City. The distance of mesh in the lowest layer was 1km. In the results of simulations, general patterns of wind and air temperature nearly coincide with the observation results and the air temperature in the central area of the urban. But the effects of the green belts in the urban were not seen. This result means that the mesh-distance should be smaller than 100m or maybe smaller than 1m. Therefore, the … More 2-dimensional model vertically integrated were used with the very small mesh and the effect of green belt were clarified. The cooling of the leaf-temperature due to the evapo-transpiration from the stomata of leaves in the green belts is most effective against the heat islands. Under the conditions with the same total number of woods and the same leaf area index of woods, the arrangement of the many small green belts is more effective than the arrangement of the few number of large green belts. Even in the 2-dimensional model the representation of eddy diffusivity is most important. Especially in the cases with the scattered small green belts, the presentations of diffusivity were showed to be very important. The characteristics of turbulence in the surface boundary layer were investigated with the analyses of observation data and theoretical investigations for the primitive equations of air(Ishida and Yasuda, 2005). The pressure terms have been showed to be very important in the turbulent energy equations. We will now continue the development of turbulent diffusivity. Less