Articles | Volume 19, issue 4
Nonlin. Processes Geophys., 19, 449–472, 2012
https://doi.org/10.5194/npg-19-449-2012
Nonlin. Processes Geophys., 19, 449–472, 2012
https://doi.org/10.5194/npg-19-449-2012

Review article 21 Aug 2012

Review article | 21 Aug 2012

Review Article: "The Lagrangian description of aperiodic flows: a case study of the Kuroshio Current"

C. Mendoza2,1 and A. M. Mancho1 C. Mendoza and A. M. Mancho
  • 1Instituto de Ciencias Matemáticas, CSIC-UAM-UC3M-UCM, C/ Nicolás Cabrera 15, Campus Cantoblanco UAM, 28049, Madrid, Spain
  • 2ETSI Navales, U. Politécnica de Madrid, Av. Arco de la Victoria 4, 28040 Madrid, Spain

Abstract. This article reviews several recently developed Lagrangian tools and shows how their combined use succeeds in obtaining a detailed description of purely advective transport events in general aperiodic flows. In particular, because of the climate impact of ocean transport processes, we illustrate a 2-D application on altimeter data sets over the area of the Kuroshio Current, although the proposed techniques are general and applicable to arbitrary time dependent aperiodic flows. The first challenge for describing transport in aperiodical time dependent flows is obtaining a representation of the phase portrait where the most relevant dynamical features may be identified. areas that are related to confinement regions. This representation is accomplished by using global Lagrangian descriptors that when applied for instance to the altimeter data sets retrieve over the ocean surface a phase portrait where the geometry of interconnected dynamical systems is visible. The phase portrait picture is essential because it evinces which transport routes are acting on the whole flow. Once these routes are roughly recognised, it is possible to complete a detailed description by the direct computation of the finite time stable and unstable manifolds of special hyperbolic trajectories that act as organising centres of the flow.