Estimation of roughness length Z₀ for Kalpakkam site

The topographic characteristics of a complex terrain site are significantly different from those at flat terrain site due to different type of wind flow conditions. The rough surface retards the wind flow from a smooth surface, which results in sharp decrease in wind speed, change in vertical profile along with atmospheric stability. The estimation of site specific surface topographic parameters such as surface roughness length Z₀ and friction velocity U* which are related to the roughness characteristics of the terrain, require wind speed profile (0-200m height from surface) for the concerned site. In this paper sector dependent Z₀ and U* for Kalpakkam site is evaluated under neutral conditions for the year 2014 using data measured in 50 m height meteorological tower at Kalpakkam. The sector dependent and nature of Z₀ and U* parameters in relation to the site topographic features and its consequence in the atmospheric dispersion models are discussed