Investigation on characteristics of thousand-meter height wind profiles at non-tropical cyclone prone areas based on field measurement

Accurate representation of the atmospheric wind profiles is very important for the relevant research works on the environmental wind engineering and wind-resistance design of buildings. Recently, the characteristics of thousand-meter height wind field in the atmospheric boundary layer (ABL) are investigated based on the field measurement by a wind profiler, which was installed in a coastal area of China (121.75 degrees E, 39.05 degrees N). Specifically, mean wind velocity profiles and wind direction profiles measured during 16 strong windy days (synoptic wind) are analyzed in the present paper. It is found that based on the agglomerative clustering analysis, the mean wind velocity profiles can be divided into two categories, namely, I and R categories. For I category, the wind velocity increases with height monotonously. While for R category, the wind velocity reaches a maximum value at a height of 500-600 m, and then recedes with height. In most cases, I category wind velocity profile can envelope that of R category, and thus becomes the main consideration for the wind - resistance design of megatall buildings. Furthermore, for I category, the log - law can be used to describe the variation of wind velocities below the height of 360 m, while the power - law is valid up to 1000 m. With the increment of total twist angle and wind velocity, the variation of measured wind directions shows a better agreement with that implied by Ekman spiral. And the total wind twist angles can reach 5 degrees-40 degrees over the first 1000m.