Wind Speed Scaling in Fully Developed Seas

Abstract

Recent tests of all generations of numerical wave models indicate that extreme wave heights are significantly underpredicted by these models. This behavior is consistent with the finding by Ewing and Laing that fully developed wave spectra do not have the universal self-similar form postulated by Pierson and Moskowitz. This paper postulates that it is inappropriate to scale fully developed seas by winds taken from a fixed level above the mean sea surface. Instead, winds should be taken from a dynamically scaled height that is linearly related to the wavelength of the spectral peak. This alternative scaling is consistent with friction-velocity scaling and yields predicted wave heights and periods that are in better agreement with the data collected by Ewing and Laing and appear to explain some of the discrepencies in results from previous studies with numerical wave models in large storms.