Comparative study of wind and turbulence characteristics during Super Typhoon Saola based on stationary and nonstationary models

An in-depth understanding of typhoon wind and turbulence characteristics in the atmospheric boundary layer is of crucial importance to structural design of high-rise structures. This study utilizes observational wind records collected from the 356-m-high Shenzhen Meteorological Gradient Tower, which is currently the tallest in Asia and the world's second tallest meteorological tower during Super Typhoon Saola to investigate typhoon wind and turbulence characteristics based on the stationary and nonstationary models. The mean wind speed and direction, power law exponent, friction velocity, and wind speed profiles are analyzed using the stationary model. Moreover, a comparative analysis employing the stationary and nonstationary models is carried out to study turbulence characteristics involving turbulence intensity, gust factor, turbulence integral length scale, power spectral density (PSD), and turbulence parameter profiles, along with a comparison to those stipulated in several building or structural design codes and standards. The results indicate that the typhoon wind speed signals exhibit strong nonstationarity, especially for longitudinal wind direction. The turbulence parameters calculated within the nonstationary framework are lower than those from the stationary model. In addition, the PSDs of the three orthogonal wind components obtained from the stationary and nonstationary model display similarities at the frequency above 0.01 Hz, and von Kármán spectra perform better in fitting the observed PSDs compared to the Kaimal spectra. The findings of this research reveal notable disparities in typhoon wind and turbulence characteristics yielded from the stationary and nonstationary models, highlighting the necessity of accounting for nonstationarity under typhoon wind conditions.