Terrain roughness and atmospheric stability at a typical coastal site

Abstract

Directional dependence of horizontal wind direction fluctuations (us) is studied at the coastal site of Madras Atomic Power Project, Kalpakkam with significant inhomogeneity in roughness element distribution around the location of measurement. 'usis measured by a potentiometric wind vane mounted on a 30 m meteorological tower. Values of ee showed as high as threefold variation for the same atmospheric stability depending on the effective roughness length of the upwind sector. Average trs values separated for sea-and land-breeze conditions, when correlated with Pasquill stability categories showed a monotonic decrease with increasing stability for land breeze but was found to increase for change from D to F category during sea breezes presumably due to the influence of an internal boundary-layer development.