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List of Abstracts 58P-Interfaces.35 ID:4410 15:35IMPACT OF TROPOSPHERIC OZONE ON VEGETATION AS SIMULATED BY THECHIMERE-ORCHIDEE COUPLED MODELAlessandro Anav 1 , Laurent Menut 1 , Dmitry Khvorostyanov 1 , Nicolas Viovy 21 Laboratoire de Meteorologie Dynamique, LMD2 Laboratoire des Sciences du Climat et de l'Environnement, LSCEContact: alessandro.anav@lmd.polytechnique.frThe impact of ozone on different European forest ecosystems is largely under-investigated, despite hugeareas of Europe are exposed to high ozone levels (> 40 ppb). We investigated the potential effects of ozoneon photosynthesis and leaf area index using a land surface model (ORCHIDEE) fully coupled with achemistry transport model (CHIMERE) for the whole year 2002. Results shown that the effect oftropospheric ozone on vegetation lead to a reduction in yearly gross primary production (GPP) of about22%, as well as a reduction in leaf area index (LAI) of 15-20%. Larger impacts have been found duringsummer, when ozone reach the higher concentrations. During these months the maximum GPP decrease isup 4 gC m-2 d-1, and the LAI reduction is up to 0.7. In general we found that crops are the most sensitive tothe ozone, while the deciduous trees exhibit a larger reduction in photosynthesis with respect to needleleavesspecies. Since CHIMERE uses the LAI computed by ORCHIDEE to account for the biogenicemissions, a LAI reduction has severe implications on the simulated atmosphere chemistry. Specifically, wefound a significant reduction in ozone precursors that lead to a change of both tropospheric and stratosphericozone concentrations, and to large changes in surface NO2 concentration.P-Interfaces.36 ID:4602 15:35Ozone pollution during stratosphere – troposphere exchange events over equatorial AfricaKassahun Ture, G. Mengistu TsiduAddis Ababa UniversityContact: kassahunture@yahoo.comBoth natural factors such as thunderstorm events and anthropogenic activities contribute to very high ozoneproduction. On the flight route from Johannesburg to Vienna enhanced ozone and relative humidity spikeswere observed by MOZAIC (Measurements of Ozone by Airbus In service airCraft). MOZAIC recordedhigh resolution in-situ ozone and relative humidity at a flying altitude of 250-200 hPa at equatorial Africa.This area is one of lightning hot spot regions of the world. We report introduction of enhanced ozone ofstratospheric origin into the troposphere during two events and the resulting pollution. Vertical cross-sectionof potential vorticity over the region of interest showed high PV intrusion below the tropopause level. BothOLR and vertical wind have indicated presence of strong convection. Cloud water content transport and highlatent heat have confirmed the existence of thunderstorm activity coupled to PV intrusion. The two distinctevents are characterized by very low ozone within the thunderstorm cloud and very high ozone ofstratospheric origin outside the thunderstorm cloud. The events have produced ambient air pollution.P-Chemistry Climate.1 ID:3354 15:35ASSESSMENT OF FACTORS RESPONSIBLE FOR CLIMATE CHANGE AND HUMAN HEALTHSapana GuptaGovt Rajiv Lochan College RajimContact: sapana.gupta02@gmail.comiCACGP-IGAC 2010 12 July, 2010