Finite-amplitude wave propagation in a stratified fluid of variable   depth
  Variable-coefficient Korteweg - de Vries equation is applied to describe the interfacial wave transformation in two-layer fluid of variable depth. The soliton dynamics in this fluid is studied. The solitary wave breaks in two transient points. One of them is the point when two-layer fluid transforms to the on-layer flow. The second one is the point where layer thickness are equaled. The soliton amplitude dependence on the thickness of lower layer is found. 
I. Didenkulova, T. Talipova, E. Pelinovsky, O. Kurkina, A. Rodin, A.   Pankratov, A. Naumov, A. Giniyatullin
physics.ao-ph nlin.SI