ESTIMATION OF THE SIGNIFICANT WAVE HEIGHT WITH X-BAND NAUTICAL RADARS

The measurement of ocean waves and surface currents with a nautical radar is based on the spatial and temporal structure analysis of radar images of the sea surface. These radar images are generated by the interaction of HHpolarized electromagnetic waves with the sea surface ripples at grazing incidence. In these radar images the sea surface is visible as sea clutter. The spatial and temporal variability of the sea clutter information is analyzed in order to extract the unambiguous directional wave spectrum, and further sea state parameters, such as peak periods, peak wave lengths, mean directions, angular spreading, etc. . A general description of the wave and surface current monitoring system WaMoS II based on a Xband radar is given. Furthermore this work deals with a method to obtain the significant wave height from sequences of nautical radar images. The method is based on a technique developed for the determination of significant wave height information from synthetic aperture radar imagery (Alpers and Hasselmann, 1982). Results of the significant wave height inferred by WaMoS II are presented for 3 different stations located in the northern and central North Sea and in the Gulf of Biscay.

[1]  D. Ross,et al.  On the detectability of ocean surface waves by real and synthetic aperture radar , 1981 .

[2]  K. Hasselmann,et al.  Spectral signal to clutter and thermal noise properties of ocean wave imaging synthetic aperture radars , 1982 .

[3]  G. Valenzuela.  Theories for the interaction of electromagnetic and oceanic waves — A review , 1978 .

[4]  Susanne Lehner,et al.  A first evaluation of ERS-1 synthetic aperture radar wave mode data , 1994 .

[5]  William J. Plant,et al.  Dominant wave directions and significant wave heights from synthetic aperture radar imagery of the ocean , 1997 .

[6]  Wolfgang Rosenthal,et al.  A three-dimensional analysis of marine radar images for the determination of ocean wave directionality and surface currents , 1985 .

[7]  F. Ziemer,et al.  Removal of ambiguity of two‐dimensional power spectra obtained by processing ship radar images of ocean waves , 1985 .

[8]  Lewis B. Wetzel,et al.  Electromagnetic Scattering from the Sea at Low Grazing Angles , 1990 .

[9]  José Carlos Nieto Borge.  Analisis de campos de oleaje mediante radar de navegacion en banda x , 1997 .

[10]  William J. Plant,et al.  Bragg Scattering of Electromagnetic Waves from the Air/Sea Interface , 1990 .

[11]  J. C. N. Borge,et al.  Use of nautical radar as a wave monitoring instrument , 1999 .

[12]  F. Ziemer,et al.  A system to monitor ocean wave fields , 1994, Proceedings of OCEANS'94.

[13]  F. Ziemer,et al.  An iterative technique to determine the near surface current velocity from time series of sea surface images , 1997, Oceans '97. MTS/IEEE Conference Proceedings.