Field measurement of typhoon winds near ground characteristics at different segment lengths in East China

In this research,the wind data was measured from a tower of 40m in height during the mild typhoon 'Meari' and ultra strong typhoon 'Muifa' near Shanghai Pudong International Airport by the East China Sea.The characteristics of turbulence intensity,gust factors,peak factor and turbulence integral scale for various segment lengths were analyzed in detail.It shows that turbulence intensity decreases with the increase of segment lengths and agrees well with Durst's results.As expected,the value measured from the mild typhoon 'Meari' is larger than that of the ultra strong typhoon 'Muifa'.Gust factors measured at 10 m are larger than those of the above heights which agree well with ASCE/SEI 7-10.The peak factor also decreases with the increase of segment lengths and agrees well with those proposed by Durst.For segment lengths more than 100 s,the value of peak factor measured from 'Meari' is larger than that of 'Muifa'.Furthermore,as the segment length increases,the turbulence integral scale will be larger,especially the lateral length scale will be larger than that of the longitudinal value,and all its components measured from 'Meari' are larger than those of 'Muifa' for various segment lengths.At a 10 m observation height,for instance,estimates of Lu vary from 27 m to 267 m for 'Meari' and 27 m to 205 m for 'Muifa',respectively.