Fifth Conference on Urban Environment


Estimation of the heat transfer resistance in the real urban canopy

Hirofumi Sugawara, National Defense Academy of Japan, Yokosuka, Kanagawa, Japan; and M. Kawahara and K. Tomine

We evaluated the heat transfer resistance to transport out of the urban canopy in the real outdoor buildings. The transfer resistance is a key parameter for the canopy heat budget but very few studies have investigated it in the urban area. The heat budget of the canopy airmass determined the heat flux out of the canopy as a residual. The heat transfer resistance was determined from this heat flux, vertical temperature gradient at canopy top and horizontal wind above the roof. The estimated heat transfer resistance was two order less than those at the building surfaces. The resistance did not depend on the vertical stability. We also analyzed the resistance-wind speed correlation and found that the representative canopy air temperature was simple average of many points. These results support our idea that the mechanically induced turbulence whose size is similar to the canopy depth controls the heat exchange between inside and outside of canopy.

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Session 6, turbulent transport and dispersion processes (in urban areas and around buildings) (parallel with session 5)
Tuesday, 24 August 2004, 8:30 AM-11:45 AM

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