Nonlinear Processes in Geophysics www.nonlin-processes-geophys.net 1023-5809 1607-7946 9 1 2002 10.5194/npg-9-37-2002 http://www.nonlin-processes-geophys.net/9/37/2002/ http://www.nonlin-processes-geophys.net/9/37/2002/npg-9-37-2002.html http://www.nonlin-processes-geophys.net/9/37/2002/npg-9-37-2002.pdf 37 49 0000-00-00 Low-frequency variability in idealised GCM experiments with circumpolar and localised storm tracks W. Müller R. Blender K. Fraedrich Universität Hamburg, Meteorologisches Institut, Hamburg, Germany Present address: MeteoSwiss, Zürich, Switzerland Idealised global circulation model simulations with circumpolar and localised (one and two) storm tracks are re-analysed to determine scaling, intermittency and phase-space structures. In a hundred year experiment with a circumpolar storm track, the spectrum <i>S(f ) </i>of the first principal component of the zonal wind fluctuations shows the following power law regimes: (a) a short-term memory between <i>f^{- -4}</i> and <i>f&nbsp;^-2</i> up to 50 days and (b) a long-term memory <i>f ^-1</i> from 50 to 400 days and <i>f ^-0.24</i> beyond 400 days, similar to observed maritime single station near-surface air temperature data. In the presence of localised storm tracks, the wave number two dominates the dynamics and a long-term memory cannot be detected. The recurrence plot is introduced as a novel tool to comprehensively visualise the evolution of the dynamical system in terms of state separations (distances) in phase space. The patterns allow for a qualitative interpretation of the underlying local phenomena in phase space, such as waves, analogs, extremes, and global regimes. Attractor dimensions are, in general, larger than 10, but they appear to be lower in the wave-dominated regimes of the double storm track experiment.