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List of Abstracts 129Contact: jeremy.vouzelaud@aero.obs-mip.frNO y species play a major role in the tropospheric chemistry by controlling ozone. In the upper troposphere,NO y is principally emitted on the form of NO x through aircraft, surface emissions, stratospheric intrusionsand lightning activity. This study aims to discriminate lightning emissions and to evaluate their influence onthe NO y and O 3 distributions over the northern midlatitudes. We use 5 years (2001-2005) of aircraftobservations (NO y , CO, O 3 , Relative Humidity) from the MOZAIC program, ground based and satelliteobservations of clouds (GOES, METEOSAT) and lightning (LIS, NLDN, ATD), combined with systematicsimulations of the FLEXPART model, in order to assess the location of NO x sources and to quantifylightning activity and the main transport agents driving NO y and O 3 distributions. During fall and winterlightning emissions are generally characterised by low NO y /CO correlation, with NO y values higher than 1ppbv and low CO. In one case sampled over the Atlantic, mean NO y (0.70 ppbv) and CO (83 ppbv)concentrations were associated with lightning activity over the Gulf of Mexico, 72 hours prior to themeasurements, with more than 80.000 CG flashes. During summer, most of the large-scale plumes with highNO y are associated with lightning NO x emissions and pollution. Nevertheless, during July 2003, a 1000 kmzonal plume influenced by clean convection was observed over the Atlantic (87 ppbv of CO, 90 ppbv. of O 3 ,2.1 ppbv of NO y ), associated with lightning activity over the Gulf of Mexico with more than 100.000 flashesone to four days before the observation. Based on the observations, transport and lightning activityproperties, we estimate the NO y and O 3 produced for each episode. It is finally expected that the outcome ofsuch an exploitation of the MOZAIC records will serve as a basis to build a comprehensive climatology ofNO y in the upper troposphere.P-Transformation.14 ID:4168 10:30Record of Concentration, δ¹³C and δ¹⁸O of Atmospheric CO over the last millennium from AntarcticIce CoresZhihui Wang 1 , Jérôme Chappellaz 2 , Mak John 11 State University of New York at Stony Brook2 Laboratoire de Glaciologie et Géophysique de l'EnvironnementContact: zhihui.wang@stonybrook.eduA record of preindustrial biomass burning over the past ~650 years in the extratropical Southern Hemisphereis derived from the carbon monoxide (CO) isotope record based on new measurements of CO concentration,δ¹³C, and δ¹⁸O from 40 Antarctic ice core samples covering the time period from 1360 to 1900. COconcentration decreases by ~25% (14 ppbv) from 1360 to around 1600, then recovers completely from 1700to the late 1800s, followed by a very slight decrease by 2000. δ¹³C and δ¹⁸O of CO decrease by about 2‰and 4‰ respectively from 1360 to 1600, then increase by about 2.5‰ and 4‰ respectively frompreindustrial times to the late 1800s. Present day values of both isotopic ratios are close to those observedduring the 1600s. Based on these observations, we conclude that biomass burning strongly modulated theCO budget during preindustrial times and decreased significantly from the early 20th century to the presentday. This decrease was nearly compensated by the concomitant methane increase, which is an isotopicallydepleted source of atmospheric CO, bringing present day CO concentrations close to its maximum levelobserved over the last 650 years.iCACGP-IGAC 2010 14 July, 2010