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  • Thomas Kurosu, Harvard-SmithsonianHCHO August 2006Ozone Monitoring ExperimentUsing space-based measurements of formaldehyde to learn about BVOC distributionsPaul Palmer, University of Edinburgh

  • Environmental factors: temperature solar irradiance leaf area index leaf ageJuly2003MEGAN Isoprene Emission Inventory

  • Global Ozone Monitoring Experiment (GOME) &the Ozone Monitoring Instrument (OMI) GOME (European), OMI (Finnish/USA) are nadir SBUV instruments Ground pixel (nadir): 320 x 40 km2 (GOME), 13 x 24 km2 (OMI) 10.30 desc (GOME), 13.45 asc (OMI) cross-equator time GOME: 3 viewing angles global coverage within 3 days OMI: 60 across-track pixels daily global coverage O3, NO2, BrO, OClO, SO2, HCHO, H2O, cloud propertiesLaunched in 2004GOME

  • GOME HCHO columnsJuly 2001Biogenic emissionsBiomass burning* Columns fitted: 337-356nm * Fitting uncertainty < continental signalsData: c/o Chance et al fractionally cloudy pixels (>40%) removed

  • Relating HCHO Columns to VOC EmissionsVOCLocal linear relationship between HCHO and EEVOC: HCHO from GEOS-CHEM CTM and MEGAN isoprene emission modelPalmer et al, JGR, 2003.Net

  • MCM HCHO yield calculationsCumulative HCHO yield [per C] pinene( pinene similar)DAYS0.4IsopreneHOURS0.5Parameterization (1ST-order decay) of HCHO production from monoterpenes in global 3-D CTMHigher CH3COCH3 yield from monoterpene oxidation delayed (and smeared) HCHO productionPalmer et al, JGR, 2006.C5H8+OH(i) RO2+NOHCHO, MVK, MACR (ii) RO2+HO2ROOHROOH recycle RO and RO2

  • GOME Isoprene Emissions: 1996-2001[1012 molecules cm-2s-1]0510Palmer et al, JGR, 2006.

  • Surface temperature explains 80% of GOME-observed variation in HCHOTime to revise model parameterizations of isoprene emissions? Palmer et al, JGR, 2006.

  • Tropical ecosystems represent 75% of biogenic NMVOC emissionsWhat drives observed variability of tropical BVOC emissions?

  • Slant Column HCHO [1016 molec cm-2]Sep 1997Nov 199719971998199920002001X = Active Fire (ATSR)Monthly ATSR FirecountsDay of YearSignificant pyrogenic HCHO source over tropicsGood: Additional trace gas measurement of biomass burning; effect can be identified largely by firecounts (see below)Bad: Observed HCHO a mixture of biogenic and pyrogenic difficult to separate without better temporal and spatial resolutionGOME

  • HCHO and Isoprene over the AmazonTrostdorf et al, 200419971998199920002001GOMEATSR Firecounts used to remove HCHO from fires

  • C/o J. KesselmeierC/o J. Saxton A. LewisAmazonAfricaCan isoprene explain the observed magnitude and variance of HCHO columns over the tropics?

  • OMI gives a better chance of estimating African BVOCsOMI Data c/o Thomas Kurosu; horizontal resolution O(10x25 km2)

  • Isoprene concentrations during AMMA July 2006 measured by the Bae146 aircraft; MODIS tree cover overlaidIsoprene data c/o Jim Hopkins and Ally Lewis, U. YorkJulOMIATSR FirecountsJul

  • Isoprene c/o Ally LewisAn increasing role for BVOCs in UK air quality?

  • 1016 [molec cm-2]OMI HCHO2
  • Final Comments

    Proper interpretation of HCHO requires an integrated approach, i.e., including surface data, lab dataInterpreting space-based HCHO data is still in its infancy new instruments bring better resolution but also new challengesWith the frequency of European heatwaves projected to increase the role of BVOCs in future UK air quality must be better quantified

    Three/four prong attack:Chemistry; Emissions: magnitude and controls; Transport

    Explain reasons for delayed production of HCHO from pinenesIsoprene is normally 2-50 pptNo temperature dependence given!!!!Same latitude as hudson bay!!No temperature dependence on isoprene emission.spruce plantation on the borders

    Tropospheric O3 production results from NO + RO2 NO2 + RO The influence of different VOCs on this step can be calculatedMuch higher total rate of NO NO2 conversion during the heatwave period (NB the graphs have different scales)Isoprene contributes substantially to O3 productionGiven the short lifetime of isoprene, it must have been generated and reacted locally