Extended Abstract (84K)9.2
Canopy albedo and representative temperatures for regularly distributed rectangular obstacles
Manabu Kanda, Tokyo Institute of Technology, Tokyo, Japan; and S. Katsuyama
Scale model experiments, using combination of 15cm x 15cm x 15cm concrete blocks, have been done for investigating the relationship between the radiation processes and urban geometry. As for the short-wave process, e a canopy albedo databasef, covering a wide range of urban geometry (plane area indexes and frontal area indexes) and different seasons, are obtained. This database can be available for validations of model studies for three-dimensional urban canopy. It is also shown that the high accurate radiation model can simulate well the observed albedo. As for the long-wave radiation, even though the thermal and turbulent similarities of scale models can not be achieved, the following qualitative discussion has been done. (1) The aerodynamic temperature, radiative temperature, complete surface temperature and satellite temperature, are compared with each other, and their dependency on the urban geometry is revealed. (2) Energy balance and heat transfer coefficients at the six different surfaces ( roof top, floor and four wall surfaces ) are estimated, using the conductive heat fluxes observed by heat plates and simulated net radiation. The heat transfer coefficients of sunlit walls are 2 to 3 times larger than those of sunshade walls. This strongly suggests the importance of the local thermal stability at each surface for the exchange processes.
Session 9, Urban radiation and energy exchanges
Wednesday, 22 May 2002, 9:30 AM-12:15 PM
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