Chaotic transport across two-dimensional jet streams

A dynamically consistent model of a jet stream modulated by Rossby waves is used to analyze the onset of chaotic transport of a passive tracer across the jet (cross-jet transport). For odd Rossby wavenumbers, a technique is developed to find a central invariant curve whose breakup signifies the onset of cross-jet transport. Amplitude and resonance mechanisms of breakup of this curve are investigated. For even-odd pairs of wavenumbers, an alternative technique is proposed for detecting cross-jet transport, based on an overlap of northern and southern stochastic layers. In this case, the Rossby-wave amplitudes required for global crossjet transport to occur are larger than those in the case of odd wavenumbers. The predicted results should be tested in laboratory experiments simulating jet streams modulated by Rossby waves.