- 期刊
賀伯颱風眼轉動可能機制探討
A Possible Mechanism for the Rotation of Typhoon Herb
摘要
由雷達回波得知1996年侵台賀伯颱風的颱風眼為精圓形。此橢圓颱風眼以144分鐘周期反鐘向旋轉。橢圓颱風眼之長軸約為30km，短軸約為20km，而颱風最大風速約為60m/s，颱風眼旋轉周期明顯大於空氣平流繞行颱風眼之時間（約為50分鐘），我們以線性與非線性理論解釋此眼之旋轉。此二理論皆強調了颱風眼附近中性位渦波的重要性。此位渦波之存在是因為颱風眼內之位渦較外部大，因此在位渦梯度上產生位渦波動。以賀伯颱風為例，線性及非線性理論的結果是一致的。我們以線性不穩度分析，了解正壓不穩度對位渦波的影響。我們並討論可以影響颱風結構的不同物理機制，對於颱風眼旋轉的影響。
並列摘要
Linear and non-linear theories are reviewed to investigate the rotation of the ecliptic eye of Typhoon Herb (1996). Both theories emphasize the importance of the neutral potential vorticity (PV) waves. Both linear and non-linear theories yield similar results for the eye rotation. Linear stability analysis was used to estimate the impact of the barotropic instability on the PV waves. We discussed physical mechanisms that might affect the typhoon eye rotation to estimate their influence to the rotation of eyes of typhoon.