Nonlinear Processes in Geophysics www.nonlin-processes-geophys.net 1023-5809 1607-7946 16 1 2009 10.5194/npg-16-33-2009 http://www.nonlin-processes-geophys.net/16/33/2009/ http://www.nonlin-processes-geophys.net/16/33/2009/npg-16-33-2009.html http://www.nonlin-processes-geophys.net/16/33/2009/npg-16-33-2009.pdf 33 42 2009-02-05 The transformation of an interfacial solitary wave of elevation at a bottom step V. Maderich T. Talipova R. Grimshaw r.h.j.grimshaw@lboro.ac.uk E. Pelinovsky B. H. Choi I. Brovchenko K. Terletska D. C. Kim Department of Marine and River Systems, Institute of Mathematical Machine and System Problems, Kiev, Ukraine Department of Nonlinear Geophysical Processes, Institute of Applied Physics, Nizhny Novgorod, Russia Department of Mathematical Sciences, Loughborough University, Loughborough, UK Department of Civil and Environmental Engineering, Sungkyunwan University, Suwon, Korea In this paper we study the transformation of an internal solitary wave at a bottom step in the framework of two-layer flow, for the case when the interface lies close to the bottom, and so the solitary waves are elevation waves. The outcome is the formation of solitary waves and dispersive wave trains in both the reflected and transmitted fields. We use a two-pronged approach, based on numerical simulations of the fully nonlinear equations using a version of the Princeton Ocean Model on the one hand, and a theoretical and numerical study of the Gardner equation on the other hand. 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