Nonlinear Processes in Geophysics www.nonlin-processes-geophys.net 1023-5809 1607-7946 14 1 2007 10.5194/npg-14-31-2007 http://www.nonlin-processes-geophys.net/14/31/2007/ http://www.nonlin-processes-geophys.net/14/31/2007/npg-14-31-2007.html http://www.nonlin-processes-geophys.net/14/31/2007/npg-14-31-2007.pdf 31 47 2007-01-30 Models for strongly-nonlinear evolution of long internal waves in a two-layer stratification T. Sakai tsakai@usc.edu L. G. Redekopp Department of Aerospace & Mechanical Engineering, University of Southern California, Los Angeles, CA 90089-1191, USA Models describing the evolution of long internal waves are proposed that are based on different polynomial approximations of the exact expression for the phase speed of uni-directional, fully-nonlinear, infinitely-long waves in the two-layer model of a density stratified environment. 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