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Characteristics of Wind Direction Shear and Momentum Fluxes within Roughness Sublayer over Sloping Terrain
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  • Journal title : Atmosphere
  • Volume 25, Issue 4,  2015, pp.591-600
  • Publisher : Korean Meteorological Society
  • DOI : 10.14191/Atmos.2015.25.4.591
 Title & Authors
Characteristics of Wind Direction Shear and Momentum Fluxes within Roughness Sublayer over Sloping Terrain
Lee, Young-Hee;
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 Abstract
We have analyzed wind and eddy covariance data collected within roughness sublayer over sloping terrain. The study site is located on non-flat terrain with slopes in both south-north and east-west directions. The surface elevation change is smaller than the height of roughness element such as building and tree. This study examines the directional wind shear for data collected at three levels in the lowest 10 m in the roughness sublayer. The wind direction shear is caused by drag of roughness element and terrain-induced motions at this site. Small directional shear occurs when wind speed at 10 m is strong and wind direction at 10 m is southerly which is the same direction as upslope flow near surface at this site during daytime. Correlation between vertical shear of lateral momentum and lateral momentum flux is smaller over steeply sloped surface compared to mildly sloped surface and lateral momentum flux is not down-gradient over steeply sloped surface. Quadrant analysis shows that the relative contribution of four quadrants to momentum flux depends on both surface slope and wind direction shear.
 Keywords
Eddy covariance data;lateral momentum flux;non-flat terrain;wind direction shear;
 Language
Korean
 Cited by
1.
비균질 도시 지표에서 측정된 에디 공분산 난류 플럭스의 불확실성 분석: 좌표계 편향 영향,이두일;이재형;이상현;

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