Study on wind characteristics of a strong typhoon in near-ground boundary layer

In order to solve the problems existing in predicting typhoon design wind speeds used for tall and special buildings, a 40-m-high meteorological tower, which is located near the coast of the East China Sea in Shanghai, was built to observe the strong winds. Based on the measurement data during Typhoon Muifa (2011), the characteristics of strong wind such as wind speeds and directions, turbulence integral scales, probability densities, power spectra, spatial correlation coefficients, and coherence coefficients were analyzed. The results revealed that the turbulence integral scales increased with height and averaging time interval. All three fluctuating wind components follow the Gaussian distribution, regardless of the measurement height and the time interval of the segment. The power spectra of longitudinal fluctuating wind velocity agreed with the von Karman spectrum. However, the power spectra of lateral and vertical fluctuating wind velocity are deviated from the von Karman model in high-frequency region. The decay rate of the autocorrelation coefficients of the longitudinal and lateral fluctuating wind velocity decreased with height. The variations of cross-correlation coefficients among three fluctuating wind display no clear regulation. The spatial cohesion coefficients follow the predictions made according to Davenport's empirical formula.