title: Generation of internal solitary waves by frontally forced intrusions in geophysical flows.
abstract: Internal solitary waves are hump-shaped, large-amplitude waves that are physically analogous to surface waves except that they propagate within the fluid, along density steps that typically characterize the layered vertical structure of lakes, oceans and the atmosphere. As do surface waves, internal solitary waves may overturn and break, and the process is thought to provide a globally significant source of turbulent mixing and energy dissipation. Although commonly observed in geophysical fluids, the origins of internal solitary waves remain unclear. Here we report a rarely observed natural case of the birth of internal solitary waves from a frontally forced interfacial gravity current intruding into a two-layer and vertically sheared background environment. The results of the analysis carried out suggest that fronts may represent additional and unexpected sources of internal solitary waves in regions of lakes, oceans and atmospheres that are dynamically similar to the situation examined here in the Saguenay Fjord, Canada.
authors.affiliation: Institut de sciences de la mer de Rimouski, Université du Québec à Rimouski, 310 allée des Ursulines, Rimouski, Québec, Canada G5L 3A1.|Laboratoire de mécanique des fluides et d'acoustique (École Centrale de Lyon, CNRS, Université Lyon 1, INSA Lyon), 69134 Lyon, France.
authors.forename: Daniel
authors.initials: D
authors.lastname: Bourgault
authors.affiliation: Institut Maurice Lamontagne, Fisheries and Oceans Canada, 850 route de la Mer, Mont-Joli, Canada G5H 3Z4.
authors.forename: Peter S
authors.initials: PS
authors.lastname: Galbraith
authors.affiliation: Institut de sciences de la mer de Rimouski, Université du Québec à Rimouski, 310 allée des Ursulines, Rimouski, Québec, Canada G5L 3A1.
authors.forename: Cédric
authors.initials: C
authors.lastname: Chavanne