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List of Abstracts 225Observations 4.3 ID:4333 09:15Observations of large HNO3-containing particles and redistribution of reactive nitrogen in the 2010winter Arctic stratosphere during RECONCILEHans Schlager 1 , Stephan Borrmann 2 , C. Michael Volk 3 , Jens-Uwe Grooß 4 , Andreas Dörnbrack 1 , FredStroh 4 , Marc Von Hobe 41 DLR-Institut für Physik der Atmosphäre, Oberpfaffenhofen, Germany2 Johannes Gutenberg Universität Mainz, Institut für Physik der Atmmosphäre, Mainz, Germany3 Bergische Universität Wuppertal, Fachgruppe Physik, Wuppertal, Germany4 Forschungszentrum Jülich, Institut für Chemie und Dynamik der Geosphäre 1, Jülich, GermanyContact:The sedimentation of HNO3-containing particles removes reactive nitrogen from air parcels in the polarvortex. Due to this denitrification chlorine remains longer in its active form and causes enhanced ozonedestruction. It is assumed that large low-density HNO3-containing particles (so called NAT rocks) aremainly responsible for the denitrification in the winter Arctic stratosphere. However, observations of theselarge HNO3-containing particles are very sparse and details of the denitrification process are not wellunderstood. This makes it difficult to predict denitrification and ozone loss accurately in models. Here wepresent the in situ detection of large HNO3-containing particles and redistribution of reactive nitrogen in the2010 winter Arctic stratosphere during the RECONCILE (Reconciliation of essential process parameters foran enhanced predictability of Arctic stratospheric ozone loss and its climate interactions) campaign using theNOy, particle, and tracer instruments on board the Geophysica high altitude aircraft. We discuss the spatialdistribution of these large particles and the ambient conditions under which they were detected. For the firsttime large HNO3-containing particles were measured embedded in nitric acid trihydrate and supercooledternary solution polar stratospheric clouds. We also observed for the first time these large particles duringevaporation in renitrified air masses. The measured denitrification and renitrification layers duringRECONCILE will be compared to model simulations of the redistribution of reactive nitrogen in the Arcticpolar vortex considering the nucleation and sedimentation of large NAT particles using the model CLaMS(Chemical Lagrangian Model of the Stratosphere).Observations 4.4 ID:4502 09:30Transport effects on the vertical distribution of ozone over marine regions surrounding IndiaShyam Lal, Shuchita Srivastava, S. VenkataramaniPhysical Research LaboratoryContact: shyam@prl.res.inAs a part of the Integrated Campaign for Aerosol, gases and radiation Budget (ICARB) conducted during18th March to 10th May, 2006, balloon borne ozone-sondes were launched to study vertical distribution ofozone over the Bay of Bengal (BoB) and the Arabian Sea (AS). A total of 29 ozone soundings were made onalternate days during the cruise. Higher ozone levels were observed above Marine Boundary Layer (MBL)up to 3 km over the BoB as compared to over the AS due to transport from the Indo-Gangetic plain, which isknown to be a polluted region. This has been confirmed using back trajectories and Potential SourceContribution Function (PSCF). These measurements also show higher levels of ozone up to 3 km in thenorthern parts of the two marine regions especially over the BoB as compared to southern regions. Theselayers are characterized by higher temperature and lower humidity which indicate advection of continentalair. On the contrary, in the free troposphere, ozone levels are lower over the BoB as compared to AS. This isdue to strong convective activities over the BoB, which lifts poor ozone air in the MBL to the freetroposphere. On the contrary, ozone rich air gets transported downwards over the AS especially over thenorthern AS. Thus, the two marine regions across the Indian sub-continent have opposite vertical transport,iCACGP-IGAC 2010 15 July, 2010