华东沿海地带台风风廓线特征的观测个例分析

利用2007年的“韦帕”、2009年的“莫拉克”、2010年的“凡亚比”和2011年的“梅花”四个台风的GPS探空数据,本文对华东近海和沿海地带的台风风廓线特征进行分析。首先求出梯度风速及其对应的高度,在此基础上利用指数律和对数律对风廓线进行拟合,并对幂指数、10米高度的地表风速和梯度风速的风速比,以及由对数律定义的常通量层高度等参数进行计算,并对梯度风高度和常通量层高度进行比较。结果表明:登陆台风沿海地带风廓线的梯度风高度和常通量层高度有明显差异。本文还对登陆台风平均风廓线的各参数进行了计算,并对梯度风高度以下风廓线偏离对数律的原因进行了讨论。

Case Studies on the Characteristics of the Coastal Wind Profiles of Three Typhoons Landing along East China

Characteristics of wind profiles were studied using the Global Positioning System (GPS) sonde data from typhoons Wipha in 2007, Morakot in 2009, Fanapi in 2010, and Muifa in 2011. The gradient wind speed and corresponding level were first obtained. The wind profiles were then fitted by the power law and the logarithmic law. The exponential index, the ratio between the wind speed at 10 m and the gradient wind speed, and the height of the constant flux layer defined by the logarithmic law were further calculated. The possible difference between the gradient wind level and the height of the constant flux layer was investigated. The results show an obvious difference between the height of the constant flux layer and the gradient wind level for the typhoons landing along East China. Moreover, the parameters of the mean wind profiles from the typhoons were calculated, and the reason for the deviation of the wind profile below the gradient wind level from the logarithmic law was discussed.