請用此 Handle URI 來引用此文件: http://hdl.handle.net/11455/45453
標題: Aerodynamic roughness over an urban area and over two farmlands in a populated area as determined by wind profiles and surface energy flux measurements
作者: Tsai, J.L.
莊秉潔
Tsuang, B.J.
關鍵字: aerodynamic roughness
urban area
farmlands
atmospheric surface layer
fingerprint area
complex terrain
boundary-layer
regional roughness
shear-stress
heat-flux
parameters
displacement
temperature
evaporation
tethersonde
期刊/報告no:: Agricultural and Forest Meteorology, Volume 132, Issue 1-2, Page(s) 154-170.
摘要: Aerodynamic roughness lengths (z(0)) were determined for an urban area and two rice paddies mixed with buildings over a complex terrain in central Taiwan. At each of the three sites, surface net radiation, ground heat flux and vertical profiles of wind speed, temperature and humidity within the atmospheric surface layer (ASL) were measured. The similarity theory of the ASL in conjunction with the energy budget equation of land surface under unstable atmospheric conditions was used to determine the roughness values. Over the urban area, the roughness was determined to be 1.2 m with a zero-plane displacement height (do) of 11 m. Over the two mixed farmlands, the roughness values were determined to be 0.2-0.5 m, 20 times higher than the values (0.008-0.02 m) for homogeneous rice paddies reported in the literature. A preliminary relationship for estimating roughness value as a function of residential fraction, farmland fraction and building height (or population density) is derived. The observations show that during the daytime, the mean height range of the ASL was 30 (+/- 6) <= (z - d(0))/z(0) <= 106 (+/- 38) and the fingerprint areas extended 1.5 km upwind from the three profile sites. (c) 2005 Elsevier B.V. All rights reserved.
URI: http://hdl.handle.net/11455/45453
ISSN: 0168-1923
文章連結: http://dx.doi.org/10.1016/j.agrformet.2005.07.008
顯示於類別:環境工程學系所

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