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List of Abstracts 30P-Sources.41 ID:4533 15:35CARIBIC passenger aircraft measurements of the distribution, seasonal cycle, and variability ofacetone in the UTLSAndreas Zahn 1 , Detlef Sprung 1 , Carl Brenninkmeijer 2 , Tanja Schuck 2 , Franz Slemr 21 IMK, KIT, Karlsruhe, Germany2 Max Planck Institute for Chemistry, Mainz, GermanyContact: carl.brenninkmeijer@mpic.deThe CARIBIC platform uses a Lufthansa Airlines Airbus A340-600 that is equipped with dedicated air inletsystem. Equipment in the monthly deployed 1.5 ton measurement container records aerosol sizes and ~100trace gases at 10-12 km cruising altitude. At the same time aerosol and air samples are collected in flight.This poster presents the recently constructed budget of acetone (measured by the PTRMS system) in theupper troposphere and lower stratosphere. More than 100 measurement flights resulted in the largestairborne dataset of acetone from the UTLS. The following findings are described: • A strong seasonalvariation of acetone occurs at the mid-latitude tropopause with maxima of ~900 pptv in summer and minimaof ~200 pptv in mid-winter. • This seasonality propagates into the LMS with rapidly decreasingconcentrations and increasing phase shift reaching ~6 weeks 2 km above the tropopause. • Probabilitydensity functions (PDFs) and the course of the seasonal variation of acetone relative to the tropopause areinterpreted regarding the in-mixing and subsequent dispersion of acetone in the LS. • The production of HOxdue to the photolysis of acetone is compared with the one following the photolysis of ozone and subsequentreaction of O(1D) with water vapour.P-Sources.42 ID:4318 15:35Evaluation of isoprene flux and its impact on oxidants and inorganic aerosols in East AsiaKyung M. Han 1 , Chul H. Song 1 , Rae S. Park 1 , Jung H. Woo 2 , Hyun K. Kim 21 Department of Environmental Science and Engineering, Gwangju Institute of Science and Technology2 Department of Advanced Technology Fusion, Konkuk UniversityContact: kmhan@gist.ac.krAs a major precursor of the ozone and SOAs (secondary organic aerosols) formations, biogenic species areof primary importance in the atmospheric chemistry. Isoprene influences the level of inorganic aerosols (i.e.sulfate and nitrate) by controlling OH radicals. However, isoprene fluxes are highly uncertain in East Asia.While isoprene fluxes from the GEIA (Global Emissions Inventory Activity) and POET (Precursors ofOzone and their Effects in the Troposphere) inventories estimate approximately 20 Tg yr -1 in East Asia,those from the MEGAN (Model of Emissions of Gases and Aerosols from Nature) and MOHYCAN (MOdelfor Hydrocarbon emissions by the CANopy) estimate approximately half of the GEIA and POETinventories. In order to evaluate and/or quantify the magnitude of the isoprene fluxes over East Asia, theHCHO columns obtained from the GOME (Global Ozone Monitoring Experiment) observations werecompared with the HCHO columns from the CMAQ (Community Multi-scale Air Quality) simulations overEast Asia. In this study, US EPA Models-3/CMAQ v4.5 modeling using the ACE-ASIA (Asia PacificRegional Aerosol Characterization Experiment) emission inventory for anthropogenic pollutants and GEIA,POET, MEGAN, and MOHYCAN emission inventories for biogenic species was carried out in conjunctionwith the Meteorological fields generated from the PSU/NCAR MM5 (Pennsylvania stateUniversity/National Center for Atmospheric Research Meso-scale Model 5) model for the summer episodesof the year 2002. In addition to an evaluation of the isoprene fluxes, we investigated the impact of theuncertainty in biogenic emission inventory on inorganic aerosol formations and variations of oxidants (OH,O 3 , and H 2 O 2 ) in East Asia. The results show that isoprene fluxes from the GEIA, POET, and MEGAN areoverestimated, particularly over South China. Also, differences in biogenic emission fluxes lead to changesiCACGP-IGAC 2010 12 July, 2010