Propagation of solitary internal waves in two-layer ocean of variable depth

The propagation of internal solitons of moderate amplitude in a two-layer ocean of variable depth is studied in terms of the Gardner and Euler equations. An analytical solution is obtained with the use of asymptotic expansions on a small parameter (bottom slope). The theoretical results are compared with the numerical modeling results. The possibility of soliton shape preservation during pulse propagation is discussed. It is obtained that, as the initial amplitude increases, the pulse deviates from the soliton shape more rapidly.