ANALYSIS OF GUST FACTOR ASSOCIATED WITH TYPHOONS ON ZHEJIANG COAST

HU Bo

doi:10.16032/j.issn.1004-4965.2017.06.005

Abstract：Using the data of typhoons affecting Zhejiang coastal islands from 2004 to 2015 and corresponding wind of coastal meteorological stations,the relationships between the gust factor and mean wind speed,intensity of typhoons,height of stations,position of islands,distance between typhoons and stations,typhoons quadrants and months are analyzed.The results show that the fluctuation and mean value of gust factor are large when the average wind speed is small,and with the same wind speed,the gust factor is large when the typhoon is strong;when the typhoon is relatively weak,the gust factor changes little with height,but when the typhoon is strong,it varies by large amplitude;the maximum gust factor appears generally in the distance of 150 ～250 km between the typhoon center and stations,and in the first and fourth quadrant of the typhoon the wind is not only stronger than in the second and third quadrant,but also the variation range of wind gust factor is wider;the gust factor in island stations near the coast is significantly smaller,and in September the fluctuation range of gust factor is smaller than that of July and August.From the analysis of typhoon circulations,it is known that the geopotential height field,vertical velocity field and humidity field are closely related with the gust factor.