On the cryogenic removal of NOy from the Antarctic polar stratosphere

• Main Authors: de Zafra, R. L., Muscari, G., Smyshlyaev, S.
• Other Authors: de Zafra, R. L.; Institute for Terrestrial and Planetary Atmospheres, State University of New York, Stony Brook, NY, U.S.A., Muscari, G.; Institute for Terrestrial and Planetary Atmospheres, State University of New York, Stony Brook, NY, U.S.A., Smyshlyaev, S.; Russian State Hydrometeorological Institute, St. Petersburg, Russia, Institute for Terrestrial and Planetary Atmospheres, State University of New York, Stony Brook, NY, U.S.A., Russian State Hydrometeorological Institute, St. Petersburg, Russia
• Format: Article in Journal/Newspaper
• Language: English
• Published: INGV 2003
• Subjects: polar stratosphere; reactive nitrogen; heterogeneous chemistry; tracer-tracer correlations; 01. Atmosphere::01.01. Atmosphere::01.01.04. Processes and Dynamics; Antarctic; Arctic; The Antarctic; Antarc*; Antarctica
• Online Access: http://hdl.handle.net/2122/889

We review current knowledge about the annual cycle of transport of nitrogen oxides to, and removal from, the polar stratosphere, with particular attention to Antarctica where the annual winter denitrifi cation process is both regular in occurrence and severe in effect. Evidence for a large downward fl ux of NOy from the mesosphere to the stratosphere, fi rst seen briefl y in the Limb Infrared Monitor of the Stratosphere (LIMS) data from the Arctic winter of 1978-1979, has been found during the 1990s in both satellite and ground-based observations, though this still seems to be omitted from many atmospheric models. When incorporated in the Stony Brook- St. Petersburg two dimensional (2D) transport and chemistry model, more realistic treatment of the NOy fl ux, along with sulfate transport from the mesosphere, sulfate aerosol formation where temperature is favorable, and the inclusion of a simple ion-cluster reaction, leads to good agreement with observed HNO3 formation in the mid-winter middle to upper stratosphere. To further emphasize the importance of large fl uxes of thermospheric and mesospheric NOy into the polar stratosphere, we have used observations, supplemented with model calculations, to defi ne new altitude dependent correlation curves between N2O and NOy. These are more suitable than those previously used in the literature to represent conditions within the Antarctic vortex region prior to and during denitrifi cation by Polar Stratospheric Cloud (PSC) particles. Our NOy -N2O curves lead to a 40% increase in the average amount of NOy removed during the Antarctic winter with respect to estimates calculated using NOy-N2O curves from the Atmospheric Trace Molecule Spectroscopy (ATMOS)/ATLAS-3 data set. Published JCR Journal open