Nonlinear Processes in Geophysics www.nonlin-processes-geophys.net 1023-5809 1607-7946 16 6 2009 10.5194/npg-16-655-2009 http://www.nonlin-processes-geophys.net/16/655/2009/ http://www.nonlin-processes-geophys.net/16/655/2009/npg-16-655-2009.html http://www.nonlin-processes-geophys.net/16/655/2009/npg-16-655-2009.pdf 655 663 2009-12-08 Seasonal variability of the subpolar gyres in the Southern Ocean: a numerical investigation based on transfer operators M. Dellnitz dellnitz@math.upb.de G. Froyland C. Horenkamp K. Padberg-Gehle A. Sen Gupta Department of Mathematics, University of Paderborn, 33095 Paderborn, Germany School of Mathematics and Statistics, The University of New South Wales, Sydney NSW 2052, Australia Institute for Transport and Economics, Dresden University of Technology, 01062 Dresden, Germany Center for Information Services and High Performance Computing (ZIH), Dresden University of Technology, 01062 Dresden, Germany Centre for Climate Change Research, The University of New South Wales, Sydney NSW 2052, Australia The detection of regions in the ocean that are coherent over an extended period of time is a fundamental problem in many oceanic applications. For instance such regions are important for studying the transport of marine species and for the distribution of nutrients. In this study we demonstrate the efficacy of transfer operators in detecting and analysing such structures. 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