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Recent developments in the GEOSChem mercury model and application to future
emission and climate scenarios
Bess Sturges Corbitt9th ICMGP
June 9th, 2009
Harvard UniversityEarth & Planetary Sciences PhD Candidatesturges@fas.harvard.edu
Collaborators:Harvard University: Daniel Jacob, Christopher Holmes, Nicole Smith Downey;MIT: Noelle Eckley Selin; Argonne National Lab: David Streets;Max Planck, Chemistry: Franz Slemr, Ralf Ebinghaus
Funding from NSF Graduate Research Fellowship Program& EPA STAR
dry deposition
Hg(0)
H
Hg(II)
H
Hg(P)
H
dry deposition
evasion
Emissions: geogenic,
soil volatilization, biomass
burning, anthropogenic
dry deposition
wet deposition
dry deposition
wet deposition
Anthropogenic
emissions
oxidation by Br
photoreduction
2D slab ocean: Hg(0), Hg(II),
nonreactive Hg
2D soil Hg
3D transport
GEOSChem atmosphereoceanland model
Reservoirs: Mg HgRates: Mg Hg/ y
Preindustrial mercury budget
Reservoirs: Mg HgRates: Mg Hg/ y
Present day mercury budget
Streets et al., 2009
Year 2006
Anthropogenic emissions
The latitudinal gradient of TGM is better represented in the simulation with oxidation of Hg(0) by bromine.
Spatial pattern of total gaseous mercury
Effect of model changes on wet deposition
Civil Aircraft for the Regular Investigation of the atmosphere Based on an Instrument Container
TGM
CARIBIC Flights 20052008
See references: Brennikmeijer, et al. 2007, Ebinghaus et al. 2007,Slemr et al. 2008
Lufthansa Airbus 3400600
Stratospheric Influence
Biomass Burning
CARIBIC CO vs O3
CO
(ppb
)
C
O3 (ppb)
CARIBIC
TGM
Vertical trend in the model and observations Vertical Profiles Along CARIBIC Flights
North Hemisphere Midlatitudes
Red bars: standard deviation of observations in 10mb pressure binsDashed lines: GEOSChem profiles for representative months for each of four seasons
Average Vertical Profile in GEOSChem
CARIBIC TGMGEOSChem Hg(0)
G
standard deviation
Decrease in observed TGM with altitude is comparable to the modeled vertical trend in Hg(0). It is possible that the oxidized mercury is partitioned to the particulate phase.
Streets et al. 2009
2050 B12050 A1B1Residential Fuel CombustionIndustrial Fuel CombustionPower Plant Fuel Combustion
Cement ManufactureCopper SmeltingLead Smelting
Zinc SmeltingArtisanal Gold ExtractionMercury Mining
Transportation Fuel CombustionBiomass BurningPig Iron ManufactureCaustic Soda Production
Future anthropogenic mercury emissions
A1B scenario most pessimistic global emissions of Hg among A1B, A2, B1 and B2 scenarios United States Hg emissions increase by 38% overall in this scenario, while the locally deposited Hg(II) increases by 52% Central American total Hg emissions increase by 240%; Hg(II) by 430%
Future increases in anthropogenic emissions increase deposition of Hg to US
B1 most optimistic scenario for United States total Hg deposition Bulk of gains come from local reduction in emissions in the Eastern half of the country United States emissions reduced by 38%; global emissions nearly constant with respect to 2006
Hg deposition reductions are possible in a lower emissions scenario
Total Hg Deposition 2006 Emissions
Total Hg Deposition 2050A1B Emissions Total Hg Deposition 2050B1 Emissions
Hg deposition predicted for Asia
Thank you for your attention
Questions?