TEMIS User Workshop, Frascati, Italy October 8-9, 2007 Formaldehyde application Derivation of updated pyrogenic and biogenic hydrocarbon emissions over the last decade Jenny Stavrakou Belgian Institute for Space Aeronomy, Brussels, Belgium

Outline HCHO chemistry, sources and sinks NMVOCs - Current emission inventories Impact of NMVOCs on O 3 and HCHO Model, data and inversion method Simulated against observed HCHO columns Inversion results over South East Asia and Africa Objective : Use HCHO columns in order to assess the performance of current biomass burning and biogenic emission inventories

HCHO chemistry, sources and sinks CH 4 OH HCHO HO 2 CH 3 O 2 NMVOC RO 2 CH 3 OOH OH NO OH CO+2HO 2 CO+H 2 CO+HO 2 +H 2 O deposition The most abundant carbonyl in the atmosphere Short-lived - lifetime on the order of a few hours Directly emitted from fossil fuel combustion and biomass burning Also formed as a high-yield secondary product in the CH 4, and NMVOC oxidation

Involvement in tropospheric photochemistry NMVOCs Non-methane hydrocarbons Oxygenated non-methane hydrocarbons Short-lived species Production of organic aerosols

Impact of NMVOCs on O 3 mixing ratios July 1997 Simulations performed with the IMAGES global CTM without NMVOCswith NMVOCs

Impact of NMVOCs on HCHO mixing ratios July 1997 without NMVOCswith NMVOCs

Emission categories Global total (Tg C /yr) Reference Biogenic 1150 Guenther et al Anthropo- genic 160 EDGAR Biomass burning 40 Lobert et al., 1999 Andreae, 2007 NMVOC global burdens difficult to derive large uncertainties in the speciation key uncertainties in global modelling of highly reactive gases serious discrepancies between inventories Potential of spaceborne HCHO columns to provide quantitative information about biomass burning and biogenic NMVOC emissions

What is the total HCHO modelled column composed of? CH 4 oxidationAnthrop. sources958 Tg109 Tg 472 Tg48 Tg Biomass burningBiogenic 2006 Annual Mean

CTM with a chemical scheme optimized with respect to HCHO production, i.e. comprising a large number of explicit NMVOCs emitted by fires and vegetation Bottom-up inventories HCHO columns An inversion method necessary to « bring back » the observed HCHO columns to top-down NMVOC emissions IMAGES global CTM, res. 5x5x40, driven by monthly mean ECMWF fields (Muller and Stavrakou, 2005), updated chemical scheme (Stavrakou et al., 2007) GFEDv1 and 2 (van der Werf et al., 2003,2004,2006), MEGAN-based database (Guenther et al., 2006, Muller et al., 2007) TEMIS dataset over Adjoint model of IMAGES (Stavrakou and Muller, 2006, Stavrakou et al., 2007) Optimize the fluxes emitted from every model grid cell and month between 1997 and 2006 Distinguish between biomass burning, and biogenic sources

SE Asia Dashed lines : prior solid lines : posterior GFEDv1 GFEDv2

: prior, : posterior GFEDv1 GFEDv2 ~35% decrease in the posterior GFEDv2 inversion very good match after optimization

Africa Dashed lines : prior solid lines : posterior GFEDv1 GFEDv2

What’s next? Objectives: first assessment of the performance of the current inventories / construction of top-down inventory for pyrogenic/biogenic NMVOC emissions over the last decade optimization of the IMAGES chemical scheme to account for HCHO production from anthropogenic NMVOCs provide updated estimates for anthropogenic NMVOCs using inversion Move towards a finer model resolution (e.g. 2 O x2.5 O ) Need for long consistent data series Plan to use HCHO columns from GOME2 (higher resolution) References: 1) Stavrakou et 2) Stavrakou et al., Evaluating the performance of pyrogenic and biogenic emission inventories against one decade of space- based formaldehyde columns, in prep. 3) Muller et al., Global isoprene emissions estimated using MEGAN, ECMWF analyss and a detailed canopy environment model 4) Stavrakou and Muller, Grid-based versus big region approach for inverting CO emissions using Measurement of Pollution in the Troposphere (MOPITT) data, JGR, ) Muller and Stavrakou, Inversion of CO and NOx emissions using the adjoint of the IMAGES model, ACP, 2005