  We consider here asymptotic models describing the evolution of internal waves
propagating between a flat rigid-lid and a variable topography. In this paper,
we derive and fully justify (in the sense of consistency, well-posedness and
convergence) a new Green-Naghdi model in the Camassa-Holm regime taking into
account large amplitude topography variations, thus relaxing the smallness
assumption on the topographic variation parameter used in [Communications on
Pure & Applied Analysis, 2015, 14 (6): 2203-2230] and hence improving the
result of the aforementioned paper.
