ABSTRACT
Probabilistic models, corrected for the finite bandwidth and taking into account wave nonlinearities, are required for more realistic description of sea waves. The second-order corrections displace the crest and trough amplitudes in a symmetric waveform upward equally and thus there is no net effect on wave height in an average sense. Analyzing the records with abnormal waves from the North Sea, Guedes Soares et al. (2003) have argued that second-order theory does not fully explain the sea conditions in which abnormal waves have appeared. Petrova et al. (2007), among others, have also found that the second-order approximation is not adequate enough to describe abnormal waves.
