Abstract. The present paper introduces an algorithm for the visualization, analysis and verification of transport and mixing processes in three-dimensional atmospheric flows. This algorithm is based on the methodology of Lagrangian descriptors (LDs), a technique from Dynamical Systems Theory. The algorithm is applied to reanalysis data in order to illustrate the evolution of the flow above Antarctica during a period of rapid changes in the southern spring of 1979. The evolution of Lagrangian coherent structures is discussed and connections with the stratosphere is examined. The results suggest that the cyclonic stratospheric polar vortex during late winter appears to extend down to the troposphere. The results are also indicative of features related to invariante manifolds that can act as deep vertical barriers to transport between vortices.

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