Searching for freak waves from in-situ buoy measurements

There are several criteria to determine a freak wave in the ocean. These criteria are independent but the results are often not the same. This study tests on four presented criteria including the ratios of H/H_1/3 and H/Hs, the kurtosis k, and the groupiness factor GF, and add one more condition (Hs>1m) on the searching of freak wave in the database of data buoy during typhoon from 1998 to 2009. The water elevation is inversed from buoy measured acceleration signal by wavelet transform. It has still not enough knowledge to know how a freak wave looks like in the real world. The result shows more confident cases of freak waves by the joint assessment of 5 conditions. In this study, we find 18 freak wave cases within the 9122 time series during Typhoons.