Introducing Building Architectural Aspects in the Urban Canopy Model

There is a growing interest for developing urban canopy models since these models could describe physical phenomena related to the environmental problems such as the urban heat island, pollution, and weather change. In this paper, we propose a new simple urban energy balance model for mesoscale simulations (SUMM). The SUMM consists of 3-D theoretical radiation scheme (Kanda et al., 2004a) and conventional heat transfer expression that uses a network of resistances (Masson, 2000; Kusaka et al., 2001). The present model allows one to readily calculate the energy balance and surface temperature at each face of the urban canopy (i.e., roof, floor, and four vertical walls) without time-consuming iterations. The SUMM model geometry is assumed to be an infinitely extended regular or staggered array of uniform buildings, each of which is composed of six faces (roof, floor, and four vertical walls). The SUMM explicitly considers the three dimensionality of surface geometry and theoretically predicts the energy balance. More importantly, several building architectural settings, namely ventilation ratio, wall and roof thickness, glazing ratio and heating and cooling effects, have been used as a new additional menus in the SUMM. One of the advantages of these additional menus is that they can facilitate the simulation in the context of a more complex real urban surface area. These menus have two distinguished cases, namely the natural cases and the heating/cooling cases. In the natural cases, only the passive components of the building, such as passive ventilation ratio, glazing ratio and thickness of roof and wall, have been taken into account during the calculation. In the heating/cooling cases, in addition to the passive components, the anthropogenic energy, from heating/cooling systems, has also been calculated. Moreover, SUMM can be automatically adjusted to the winter and summer model. The simulation results showed that various building architectural settings in the natural cases have no significant impacts on the urban energy balance in the reference height. Whereas in the heating and cooling cases, even though heating intensity is generally lower than the incoming solar flux, the anthropogenic heating from heating and cooling systems has a significant contribution. Furthermore, we observed significant effect from the various architectural settings on the change of temperature inside the building