26th Conference on Hurricanes and Tropical Meteorology

Wednesday, 5 May 2004
The eyewall evolution and intensity change in a landfalling typhoon (Formerly Paper Number 12A.1)
Richelieu Room (Deauville Beach Resort)
Hsiu-Ju Cheng, National Taiwan University, Taipei, Taiwan; and C. C. Wu and Y. Wang
Poster PDF (329.2 kB)
The eyewall evolution and intensity change of Typhoon Zeb (1998) before, during, and after its landfall at Luzon were studied from a series of numerical simulations. It is found that the terrain plays a critical role in leading to such an eyewall evolution: first an eyewall contraction just before landfall, a following breakdown at and just after landfall, and then a reformation of the eyewall after the storm returned to the ocean. The angular momentum budget is carried out to understand the interactions between eddies and the mean vortex circulation at the different stages of the eyewall evolution. The roles of terrain and ocean are also analyzed to show the effect of boundary layer processes. It is believed that the improved understanding of the physical mechanisms responsible for such an eyewall evolution can improve the skill in predicting the structure and intensity changes of tropical cyclones in general and landfalling ones in particular.

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