An observed extreme large wave

Typhoon generates large waves. The existence of gigantic maximum wave heights during a typhoon or hurricane in the world oceans is by no means new. Wang et al. (2005) reported a Hmax of 27.7m and Holliday et al. (2006) discovered a recorded Hmax of 29.1m from pressure gage and shipborne wave recorder respectively. In this paper, an extreme large wave observed from a data buoy named Gueisandao located at northeast Taiwan coast water in October 2007 during typhoon Krosa is reported. The maximum trough-to-crest wave height is 32.3m. Spectral and time series analyses are applied to check the data. It is shown this extreme wave record is well qualified. We try to find the reason of how this extreme wave occurred. By the evolution of directional wave spectra at Gueisandao Buoy, it is found that interaction of two opposite component waves which one was coming directly from typhoon center and the other one was diffracted when typhoon generated waves pass through an Island, may be one of the possibilities to form such an extreme wave.