2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/80616We study the dynamics of two-dimensional coherent structures in planetary atmospheres and oceans. We derive the Zakharov-Kuznetsov equation for large scale motion from the barotropic quasigeostrophic equation in a weakly nonlinear, long wave approximation. We consider coherent structures emerging out of an instability caused by a narrow jet-like meanflow. We use multiple scale analysis combined with asymptotic matching.12 pagesPattern Formation and Solitonstext