Quantification of transport across the boundary of the lower stratospheric vortex during Arctic winter 2002/2003 G. Günther1, R. Müller1, M. von Hobe1, F. Stroh1, P. Konopka1, and C. M. Volk2 1Institute for Chemistry and Geodynamics (ICG-1), Forschungszentrum Jülich, 52425 Jülich, Germany 2Institute for Meteorology and Geophysics, Universität Frankfurt, 60325 Frankfurt, Germany
Abstract. Strong perturbations of the Arctic stratosphere during the winter 2002/2003 by
planetary waves led to enhanced stretching and folding of the vortex. On two
occasions the vortex in the lower stratosphere split into two secondary vortices
that re-merged after some days. As a result of these strong disturbances the role
of transport in and out of the vortex was stronger than usual. An advection and
mixing simulation with the Chemical Lagrangian Model of the Stratosphere (CLaMS)
utilising a suite of inert tracers tagging the original position of the air masses
has been carried out. The results show a variety of synoptic and small scale
features in the vicinity of the vortex boundary, especially long filaments peeling
off the vortex edge and being slowly mixed into the mid latitude environment. The
vortex folding events, followed by re-merging of different parts of the vortex led
to strong filamentation of the vortex interior. During January, February, and March
2003 flights of the Russian high-altitude aircraft Geophysica were performed
in order to probe the vortex, filaments and in one case the merging zone between
the secondary vortices. Comparisons between CLaMS results and observations
obtained from the Geophysica flights show in general good agreement.
Several areas affected by both transport and strong mixing could be identified,
allowing explanation of many of the structures observed during the flights.
Furthermore, the CLaMS simulations allow for a quantification of the air mass
exchange between mid latitudes and the vortex interior.
The simulation suggests that after the formation of the vortex was completed, its
interior remaind relatively undisturbed. Only during the two re-merging events
were substantial amounts of extra-vortex air transported into the polar
vortex. When in March the vortex starts weakening additional influence from lower
latitudes becomes apparent in the model results.
In the lower stratosphere export of vortex air leads only to a fraction of about
5% polar air in mid latitudes by the end of March. An upper limit for the
contribution of ozone depleted vortex air on mid-latitude ozone loss is derived,
indicating that the maximum final impact of dilution is on the
order of 50%.
Citation: Günther, G., Müller, R., von Hobe, M., Stroh, F., Konopka, P., and Volk, C. M.: Quantification of transport across the boundary of the lower stratospheric vortex during Arctic winter 2002/2003, Atmos. Chem. Phys., 8, 3655-3670, doi:10.5194/acp-8-3655-2008, 2008.