HR: 1340h
AN: A13D-0976    [Abstracts]
TI: Chemical Ozone Loss in the Arctic and Antartic Stratosphere Deduced From Ozone-Tracer Relations
AU: * Müller, R
EM: ro.mueller@fz-juelich.de
AF: Forschungzentrum Jülich (ICG-I), Leo Brandt Str., Jülich, 52425 Germany
AU: Tilmes, S
EM: tilmes@ncar.edu
AF: Forschungzentrum Jülich (ICG-I), Leo Brandt Str., Jülich, 52425 Germany
AU: Tilmes, S
EM: tilmes@ncar.edu
AF: NCAR (ACD), Table Mesa Drive, Boulder, CO 80305 United States
AU: Konopka, P
EM: p.konopka@fz-juelich.de
AF: Forschungzentrum Jülich (ICG-I), Leo Brandt Str., Jülich, 52425 Germany
AU: Grooss, J
EM: j.-u.grooss@fz-juelich.de
AF: Forschungzentrum Jülich (ICG-I), Leo Brandt Str., Jülich, 52425 Germany
AU: Jost, H
EM: hjost@mail.arc.nasa.gov
AF: Bay Area Environmental Research Institute, 560 Third St. West, Sonoma, CA 95476 United States
AU: Russell, J M
EM: james.russell@hamptonu.edu
AF: Hampton University, Center for Atmos. Sci., Hampton, VA 23668 United States
AB: Tracer-tracer relations have been used for a long time to separate physico-chemical change from change caused by transport processes. In particular, for more than a decade, ozone-tracer relations have been used to quantify ozone loss in the polar vortex. The application of ozone-tracer relations for quantifying ozone loss relies on two hypotheses; that a compact ozone-tracer relation is established in the `early' polar vortex and that any change of the ozone-tracer relation in the vortex over the course of winter is caused predominantly by chemical ozone loss. We revisit this issue analysing various sets of measurements and the results from several models. We find that mixing across the polar vortex edge impacts ozone-tracer relations in a way that may solely lead to an underestimation of chemical ozone loss and not to an overestimation. Further, differential descent in the vortex and internal mixing has only a negligible impact on ozone loss estimates. Moreover, the representation of mixing in three-dimensional atmospheric models can have a substantial impact on the development of tracer relations in the model. Rather compact ozone-tracer relations develop ---in agreement with observations--- in the vortex of a Lagrangian model (CLaMS) where mixing is anisotropic and driven by the deformation of the flow. We conclude that, if a reliable `early vortex' reference can be obtained and if vortex measurements are separated from mid-latitude measurements, ozone-tracer relations constitute a reliable tool for the quantitative determination of chemical ozone loss in the polar vortex. Ozone-tracer relations are used for estimating chemical ozone loss for several Arctic winters between 1991 and 2005 based on HALOE measurements. We find a close, linear relationship between chemical ozone loss and the potential for formation of polar stratospheric clouds for both Arctic and Antarctic winters. However, the slope of the linear relationship is much steeper for Arctic conditions because chemical ozone loss is almost saturated in Antarctica in early spring. Therefore, would stratospheric temperatures in the Arctic decrease owing to climate change, future chemical ozone loss in the Arctic could possibly exceed Antarctic values.
DE: 0300 ATMOSPHERIC COMPOSITION AND STRUCTURE
SC: Atmospheric Sciences [A]
MN: Fall Meeting 2005