Structure of large-amplitude internal solitary waves

The horizontal and vertical structure of large-amplitude internal solitary waves propagating in stratified waters on a continental shelf is investigat ed by analyzing the results of numerical simulations and in situ measuremen ts. Numerical simulations aimed at obtaining stationary, solitary wave solu tions of different amplitudes were carried out using a nonstationary model based on the incompressible two-dimensional Euler equations in the frame of the Boussinesq approximation. The numerical solutions, which refer to diff erent density stratifications typical for midlatitude continental shelves, were obtained by letting an initial disturbance evolve according to the num erical model. Several intriguing characteristics of the structure of the si mulated large-amplitude internal solitary waves Like, for example, waveleng th-amplitude and phase speed-amplitude relationship as well as form of the locus of zero horizontal velocity emerge, consistent with those obtained pr eviously using stationary Euler models. The authors' approach, which tends to exclude unstable oceanic internal solitary waves as they are filtered ou t during the evolution process, was also employed to perform a detailed com parison between model results and characteristics of large-amplitude intern al solitary waves found in high-resolution in situ data acquired north and south of the Strait of Messina, in the Mediterranean Sea. From this compari son the importance of using higher-order theoretical models for a detailed description of large-amplitude internal solitary waves observed in the real ocean emerge. Implications of the results showing the complexity related t o a possible inversion of sea surface manifestations of oceanic internal so litary waves into characteristics of the interior ocean dynamics are finall y discussed.