13.1
Effects of greenery patches on urban climate: A numerical experiment
PAPER WITHDRAWN
J. G. Sang, Peking Univ., Beijing, China
Numerical experiments were conducted to simulate the advection processes between the greenery patch and architectural complex , and the water and energy balance processes among air, vegetation canopy and buildings. A biosphere parameterization scheme, which was developed according to the data of field experiment carried out in Beijing City, is used to describe the surface and subsurface water transfer processes and the effects of water on the surface energy budget. In this scheme the parameters such as the volumetric surface soil moisture, the bulk soil moisture,the ground surface and vegetation medium temperature, and soil mean temperature etc. are included to represent the evaporarion from soil, transpiration from the canopy,latent heat flux, sensible heat flux as well as soil heat flux. The architectural complex is treated as porous medium. A space averaging technique allows computations inside the urban canopy layer with accouting for the volume of buildings and canopy structures. Total radiation, sensible heat, substrate heat, anthropogenic heat exchange between buildings and air are computed for architectural complex. The model is used to investigate the influences of greenery patches with different sizes and vegetation types on the microclimate of the urban canopy layer. Results indicate that the woodland or lawn with horizontal range of 50-100m has obvious influences on the distribution of temperature and moisture within the architectural complex. The relationship of the effects of greener patches with building density , building heights , street canyon width etc. is also discussed.
Session 13, Urban vegetation/atmosphere interactions
Thursday, 17 August 2000, 3:30 PM-5:15 PM
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