Abstract
Surface-layer features with different prevailing wind directions for two distinct seasons (Southwest Monsoon and Northeast Monsoon) on the west coast of India are studied using data obtained from tower-based sensors at a site located about 500 m from the coast. Only daytime runs have been used for the present analysis. The surface boundary-layer fluxes have been estimated using the eddy correlation method. The surface roughnessz 0 obtained using the stability-corrected wind profiles (Paulson, 1970) has been found to be low for the Southwest monsson season. For the other season,z 0 is relatively high. The drag coefficientC D varies with height in the NE monsoon season but not in the season with lowz 0. This aspect is reflected in the wind profiles for the two seasons and is discussed in detail. The scaling behaviour of friction velocityu * and the turbulence intensity of longitudinal, lateral and vertical winds σu, σv and σw, respectively) are further examined to study their dependence on fetch. Our study shows that for the non-dimensional case, σu/u* and σv/u* do not show any surface roughness dependence in either season. On the other hand, for σw/u* for the season with lowz 0, the values are seen to agree well with that of Panofskyet al. (1977) for homogeneous terrain whereas for the other season with highz 0, the results seem to conform more to the values observed by Smedman and Högström (1983) for coastal terrain. The results are discussed in the light of observations by other investigators.
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Ramachandran, R., Prakash, J.W.J., Gupta, K.S. et al. Variability of surface roughness and turbulence intensities at a coastal site in India. Boundary-Layer Meteorol 70, 385–400 (1994). https://doi.org/10.1007/BF00713777
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DOI: https://doi.org/10.1007/BF00713777