On the Growth of Wind-Generated Waves in a Swell-Dominated Region in the South Atlantic

Abstract

The growth of surface gravity waves is investigated in an open sea region dominated by swell. An extensive database was collected by the Brazilian Oil Company during the South Atlantic Deep Water Program (PROCAP) in Campos Basin, off coast of Rio de Janeiro. This is the most important petrolic basin in Brazil where tens of drilling platforms are located. The data set contains over 5800 directional wave spectra measured by a heave-pitch-roll buoy in conjunction with meteorological data. A spectral approach is applied in a novel method for the partitioning of sea from swell and for the adjustment of the spectral parameters. The wave growth is investigated and the regression laws of the windsea extracted from the swell-contaminated spectra are compared to earlier works in sheltered areas. It is shown that, on the grounds of the equilibrium range theory, the high-frequency spectral level (the alpha parameter) scale with the reciprocal wave age in the same manner as in unimodal swell-free spectra.