Berlin 2005 – scientific programme

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EP: Extraterrestrische Physik

EP 2: CAWSES

EP 2.13: Talk

Friday, March 4, 2005, 18:00–18:15, TU BH349

Enhanced NOx-induced ozone loss in the Arctic middle stratosphere during the 2002/03 winter and spring. — •Paul Konopka, Jens-Uwe Grooß, Martin Kaufmann, and Rolf Müller — Forschungszentrum Jülich, ICG-I, 52425-Jülich

High resolution, 3D simulations of tracer distribution in the Arctic tratosphere during the winter and spring 2002/2003 (SOLVE2/VINTERSOL) have been conducted with the Chemical Lagrangian Model of the Stratosphere (CLaMS). CLaMS is based on a Lagrangian formulation of the tracer transportand, unlike Eulerian CTMs, considers an ensemble of air parcels on a time-dependent irregular grid that is transported by use of the 3d-trajectories. The NOx-induced ozone loss driven by the so-called summertime NOx chemistry is a well-known photolytical mechanism mainly occurring in the middle and upper tratosphere over polar regions in spring and summer. By transporting ozone in CLaMS as a passive tracer, the chemical ozone loss can be deduced as the difference between the observed (HALOE, POAM, MIPAS) and simulated ozone profiles. Our results show that at least for 2002/03 winter the column ozone loss driven by the NOx chemistry is of the same magnitude as the chlorine-induced ozone loss in the lower stratosphere. The NOx-induced ozone decline mainly occurs in high latitudes near the vortex edge, as the stratosphere undergoes a transition from a strong mixing situation in the late winter/spring, when the vortex breaks down (top-down process), to a weakly stirred situation in summer.We discuss NOx sources which are responsible for this ozone loss, in particular the amount of stratospheric NOx that can be traced back to their sources above the stratopause.