<title>Application of computational geometry to the analysis of directional wave spectra as measured by hf radar</title>

Abstract

Directional ocean wave spectra are extremely important to oceanographers in that they provide full quantative information on the wave systems present on the ocean surface. The use of H. F. radar as a remote sensing tool for the direct measurement of directional ocean spectra has, in recent years, been shown to be extremely effective and reliable. It possesses a number of characteristics that are important for remote sensing. Namely these are excellent offshore range (typically 150 - 200 km), and excellent frequency, spatial, and temporal resolution. It is the frequency resolution that is furnishing scientists with a quality of directional ocean spectra that is unrivalled. In analysing the measured spectra, it is useful to consider the ocean surface as being made up of a number of combined wave systems. These would be for example a mixed wind and swell wave system. These systems manifest themselves as separate modes in the directional spectra and, may be analysed separately in order to individually parameterize them. Work at Sheffield has concentrated on how this analysis may be performed automatically. This involves the segmentation of the spectra into the individual modes followed by parameter extraction. Presented will be results of how computational geometry, in particular the Voronoi diagram, and recent results from mathematical morphology are being employed to pIovide a system capable of roviding such analysis.