Robust AR Representations of Ocean Spectra

A general criterion to qualify ARMA representations of ocean spectra is presented. An objective criterion to qualify simulators becomes the key element to justify the selection or rejection of ARMA representations for practical applications. A technique to calculate robust AR representations appears to be the natural engineering solution to overpass the instability and poor results provided by classical methods. An addition of modicum white noise (0.0025 $m_0$) to the theoretical JONSWAP-type spectra is proved to be sufficient to generate robust AR representations free of instabilities and showing an excellent qualification according to the general criterion justified for most ocean engineering applications.