Development of a Multi-Layer Urban Canopy Model for the Analysis of Energy Consumption in a Big City: Structure of the Urban Canopy Model and its Basic Performance

A multilayer one-dimensional canopy model was developed to analyze the relationship between urban warming and the increase in energy consumption in a big city. The canopy model, which consists of one-dimensional diffusion equations with a drag force, has three major parameters: building width, distance between buildings, and vertical floor density distribution, which is the distribution of a ratio of the number of the buildings that are taller than some level to all the buildings in the area under consideration. In addition, a simplified radiative process in the canopy is introduced. Both the drag force of the buildings and the radiative process depend on the floor density distribution. The thermal characteristics of an urban canopy including the effects of anthropogenic heat are very complicated. Therefore, the focus of this research is mainly on the basic performance of an urban canopy without anthropogenic heat. First, the basic thermal characteristics of the urban canopy alone were investigated. The canopy model was then connected with a three-dimensional mesoscale meteorological model, and on-line calculations were performed for 10 and 11 August, 2002 in Tokyo, Japan. The temperature near the ground surface at the bottom of the canopy was considerably improved by the calculation with the canopy model. However, a small difference remained between the calculation and the observation for minimum temperature. Deceleration of the wind was well reproduced for the velocity at the top of the building by the calculation with the canopy model, in which the floor density distribution was considered.

[1]  M. Nakanishi.  Large-Eddy Simulation Of Radiation Fog , 2000 .

[2]  Yukihiro Kikegawa,et al.  Temperature Variation in the Urban Canopy with Anthropogenic Energy Use , 2003 .

[3]  Marek Uliasz,et al.  Some numerical urban boundary-layer studies , 1982 .

[4]  V. Ca,et al.  A k-*epsiv Turbulence Closure Model For The Atmospheric Boundary Layer Including Urban Canopy , 2002 .

[5]  H. Kondo,et al.  Development of a numerical simulation system toward comprehensive assessments of urban warming countermeasures including their impacts upon the urban buildings' energy-demands , 2003 .

[6]  J. Kondo,et al.  Numerical studies on the two-dimensional flow in horizontally homogeneous canopy layers , 1976 .

[7]  A. Martilli.  Numerical Study of Urban Impact on Boundary Layer Structure: Sensitivity to Wind Speed, Urban Morphology, and Rural Soil Moisture , 2002 .

[8]  A. Clappier,et al.  An Urban Surface Exchange Parameterisation for Mesoscale Models , 2002 .

[9]  Arthur H. Rosenfeld,et al.  Summer heat islands, urban trees, and white surfaces , 1990 .

[10]  Valéry Masson,et al.  A Physically-Based Scheme For The Urban Energy Budget In Atmospheric Models , 2000 .

[11]  Yukihiro Kikegawa,et al.  A Study on the Effect of Anthropogenic Heat on the Temperature Distribution in the Urban Canopies , 1998 .

[12]  Hiroaki Kondo,et al.  A Study on the Urban Thermal Environment Obtained through One-Dimensional Urban Canopy Model , 1998 .

[13]  Keisuke Hanaki,et al.  Thermal environment simulation for three dimensional replacement of urban activity , 1999 .

[14]  Hiroaki Kondo,et al.  The Thermally Induced Local Wind and Surface Inversion over the Kanto Plain on Calm Winter Nights , 1995 .

[15]  M. Aida,et al.  Urban albedo as a function of the urban structure — A two-dimensional numerical simulation , 1982 .

[16]  Nobuko Saigusa,et al.  A Numerical Simulation of the Daily Variation of CO2 in the Central Part of Japan —Summer Case— , 2001 .

[17]  M. Aida,et al.  Urban albedo as a function of the urban structure — A model experiment , 1982 .

[18]  J. Kondo,et al.  The Influence of Canopy Structure and Density upon the Mixing Length within and above Vegetation , 1990 .

[19]  H. Kondo,et al.  A Simple Single-Layer Urban Canopy Model For Atmospheric Models: Comparison With Multi-Layer And Slab Models , 2001 .

[20]  Takashi Asaeda,et al.  Building canopy model for the analysis of urban climate , 1999 .

[21]  Kanzaburo Gambo,et al.  Notes on the Turbulence Closure Model for Atmospheric Boundary Layers , 1978 .

[22]  Walter Jürges.  Der Wärmeübergang an einer ebenen Wand , 1924 .

[23]  A. Blackadar.  The vertical distribution of wind and turbulent exchange in a neutral atmosphere , 1962 .

[24]  Itsushi Uno,et al.  Numerical modeling of the nocturnal urban boundary layer , 1989 .

[25]  Keisuke Hanaki,et al.  Impact of anthropogenic heat on urban climate in Tokyo , 1999 .

[26]  J. Kondo,et al.  Air-sea bulk transfer coefficients in diabatic conditions , 1975 .