Boundary layer wind structure from observations on a 325 m tower

This paper is concerned with vertical distributions of mean wind speed and atmospheric turbulence characteristics over a typical urban area. The wind data were measured from more than 30 anemometers installed at 15 different height levels on the 325 m high Beijing Meteorological Tower during numerous windstorms. Profiles of mean wind speed are presented based on the field measurements and are compared with empirical models’ predictions. Aerodynamic parameters of atmospheric boundary layer are determined from the measured wind speed profiles. Furthermore, wind velocity data in longitudinal, lateral and vertical directions, which were recorded by ultrasonic anemometers at three height levels during windstorms, are analyzed and discussed. Atmospheric turbulence information such as turbulence intensity, gust factor, turbulence integral length scale and power spectral densities of the three-dimensional fluctuating wind velocity are presented and used to evaluate the adequacy of the existing theoretical and empirical models. A comparative study between the measured profiles of turbulence parameters and those estimated by AIJ-RLB-1996 and ASCE (1999) is performed. The objective of this study aims to provide useful information on boundary layer wind characteristics for the wind-resistant design of tall buildings and high-rise structures in urban areas.