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利用近岸海上气象平台对登陆台风“黑格比”近海层风廓线观测资料,计算分析了近海层大气的湍流动量通量交换参数,以期认识高风速情况下的海气动量交换特征。数据分析结果显示,当海面上方10 m处风速U10≤24 m/s时,摩擦速度(U*)随风速的增大而增大,当U10>24 m/s时,U*呈饱和趋势。海面粗糙度长度(Z0)、拖曳系数(Cd)在低风速(U10≤6 m/s)随风速的增大而减小,在U10处于6~24 m/s之间时,Z0、Cd随风速的增大而增大,当U10>24 m/s时,Z0、Cd达到极值后开始减弱。Z0、Cd极值出现在U10为24~28 m/s之间。并对高风速时拖曳系数衰减现象的对应机制进行了讨论。另外,还探讨了台风期间的阵风因子(G(t,T))等参数的演变特征。
Based on the observation data of the wind profile near the surface of the typhoon and the “Hagupit” landing platform, the parameters of turbulent momentum flux exchange in the offshore atmosphere are calculated and analyzed in order to know the characteristics of the momentum exchange . The results of data analysis show that the friction velocity (U *) increases with the increase of wind speed when the wind speed at 10 m above the sea surface is U10 ≤ 24 m / s, and U * tends to be saturated when U10> 24 m / s . The sea surface roughness length (Z0) and drag coefficient (Cd) decreased with the increase of wind speed at low wind speed (U10≤6 m / s). When U10 was between 6 and 24 m / s, Z0 and Cd With the increase of wind speed, when U10> 24 m / s, Z0, Cd began to weaken after reaching the extreme value. Z0, Cd extreme value appears in U10 is between 24 ~ 28 m / s. The corresponding mechanism of the drag coefficient attenuation at high wind speed is also discussed. In addition, evolution characteristics of gust factors (G (t, T)) and other parameters during typhoon are also discussed.