temis user workshop, frascati, italy october 8-9, 2007 formaldehyde application derivation of...
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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 O3 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
CH4
OH
HCHO
HO2
CH3O2
NMVOC
RO2
CH3OOHOH OH
NO
OH
CO+2HO2
CO+H2
CO+HO2+H2O
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 CH4, 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 O3 mixing ratios
July 1997
Simulations performed with the IMAGES global CTM
without NMVOCs with NMVOCs
Impact of NMVOCs on HCHO mixing ratios
July 1997
without NMVOCs with NMVOCs
Emission categories
Global total
(Tg C /yr)Reference
Biogenic 1150 Guenther et al. 1995
Anthropo-genic 160 EDGAR
Biomass burning 40
Lobert et al., 1999
Andreae, 2007
C5H843%
C10H1611%
ORVOC23%
OVOC23%
85%
12%3%
Biogenic
Anthropogenic
Biomassburning
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?
CH4 oxidation Anthrop. sources958 Tg 109 Tg
472 Tg48 TgBiomass burning Biogenic
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 1997-2006
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. 2Ox2.5O)
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, 2006
5) Muller and Stavrakou, Inversion of CO and NOx emissions using the adjoint of the IMAGES model, ACP, 2005