Fractal dimension characteristics of wind speed time series under typhoon climate

Abstract

On the basis of fractal theory, the fractal dimension is assumed to be a quantitative parameter to assess the complexity of fluctuations and persistence of wind speeds. This study examines characteristics of the fractal dimension of wind speeds during three typhoons based on field measurements. The time series of all wind speeds exhibited three prominent stages and excellent synchronization among four heights (35 m, 55 m, 75 m, and 95 m). The results show that peak regions of the fractal dimension occur at the times of arrival and departure of a typhoon, and the mean values of fractal dimension in the high wind speed stage reach the maximum. The wind speed time series are anti-persistent, with the fractal dimension varying from 1.55 to 1.75 throughout the typhoon. Moreover, the values of fractal dimension rely slightly on the length of wind speed data, and are positively correlated with the mean horizontal wind speed. This study aims to enhance the understanding of fractal features in wind speeds under typhoon climate and these findings on the characteristics of the fractal dimension can be incorporated into the simulation algorithms of typhoons.