WIND EVOLUTION CHARACTERISTICS OF SEVERE TROPICAL STORM FUNG WONG (1416) AFTER MAKING LANDFALL IN ZHEJIANG PROVINCE

YAO Ri-sheng; TU Xiao-ping; HUANG Xuan-xuan; GU Xiao-li; ZHENG Zheng

doi:10.16032/j.issn.1004-4965.2017.04.002

Abstract：By using the observation data from a Doppler radar at Ningbo,automatic weather stations in Zhejiang Province,and an observation tower on the Hill Liangmaoshan at Ningbo,a comprehensive analysis was conducted on the wind field evolution of the severe tropical storm (STS) Fung Wong (1416) after its landfall in Zhejiang Province.Results show that Fung Wong was asymmetric with strong winds (scale 8 and up) in the front and to the right ofthe STS center.In the front,the radii of maximum velocities (RMV) remained around 60 km without much change,and the maximum wind band was about 50 km wide.To the right of the STS center,the RMW were 80～120 km away from the center with an ascending trend while the STS was going northwards,and the maximum wind band was about 100 km wide.The RWV showed few vertical differences both in the front and to the right of the STS center.The TREC winds were strongest at the altitude of lkm in the front,and decreased with height above it;on the right side,wind speeds showed little vertical variation between 1～3 km,much smaller compared to that in the front.The TREC winds and gradient observations from the tower on the Hill Liangmaoshan show that several wind speed maxima existed at around 159 m and 2～4 km.A constant flux layer height of Fung Wong was about 159 m.Within the constant flux layer,the wind profile followed the logarithm law.When the tower was in the front right side of the STS center,the gust coefficients decreased with altitude;while the tower was near or at the right rear of the center,the gust coefficients increased obviously with height and the vertical differences decreased.Above the constant flux layer,at 159～318 m,the wind profile did not follow the logarithm law and the gust coefficients showed little differences with height.