Asian Sources of Methane and Ethane Y. Xiao, D.J. Jacob, J. Wang, G.W. Sachse, D.R. Blake, D.G....
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Asian Sources of Methane and Ethane Y. Xiao, D.J. Jacob, J. Wang, G.W. Sachse, D.R. Blake, D.G. Streets, et al. Atmospheric Chemistry Modeling Group Harvard University June, 2002 OBJECTIVE: use a global 3-D model interpretation of the CH 4 -C 2 H 6 -CO correlations observed in TRACE-P as constraints on the sources of these gases
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Transcript of Asian Sources of Methane and Ethane Y. Xiao, D.J. Jacob, J. Wang, G.W. Sachse, D.R. Blake, D.G....
Asian Sources of Methane and Ethane
Y. Xiao, D.J. Jacob, J. Wang, G.W. Sachse, D.R. Blake, D.G. Streets, et al.
Atmospheric Chemistry Modeling GroupHarvard University
June, 2002
OBJECTIVE: use a global 3-D model interpretation of the CH4-C2H6-CO correlations observed in TRACE-P as constraints on the sources of these gases
Observed correlations
C2H6-CH4 CO-C2H6
GEOS-CHEM C2H6 simulation during TRACE-P
• 4x5 horizontal resolution, 48 vertical levels
• Monthly OH from full chemistry simulation(CH3CCl3 lifetime ~ 5.6 years)
• Driven by DAO assimilated meteorological data during TRACE-P
Sink: reaction with OH, lifetime: 1-3 months
Model setup:
Asian emissions are superimposed with Y2K D. Streets emissions
Sources Global
Asia Asia*
Natural gas leakage scaled to the corresponding sources of CH4
[J.Wang, 2002, Fung et al., 1991]Uniform mass ratio of C2H6/CH4: 8%
3.0
1.73 0.58Natural gas venting
0.8
Coal mining 2.5
Biomass burning Scaled to CO BB emission [Duncan et al., 2001] w/ seasonal variation 2.0 0.62 0.60
Biofuel useInventory: Yevich and Logan [2001] EF: Andreae and Merlet [2001]
2.0 1.24 1.22* D. Streets inventory
The model has a distinct bias in the boundary layer
European industrial source has large influence in Asian outflow
ObservationModel22.2
6.7
25.0
6.3
21.4
6.5
27.3
6.2
Streets Logan
Bb0.6/2/(70*12/28)
=20~5.5
Bf 1.22/2/(104*12/28)=32
~20.
Ind.
0.58/2/(70*12/28)=22
Asian C2H6/CO emission ratio
(moleC2H6/moleCO*10-3)
Free
Troposphere
Boundary
Layer
C2H6-CO correlation
Preliminary inventory of CH4 sources
Animals
Gas ventin
g
Gas leakage
Landfills
Coal miningTerm
ite
sSoil s
inkRice
paddiesWetland
sBiomass
burning
Application of CH4 simulation to TRACE-P
? Background CH4
Initiate the model with observed latitudinal distribution from CMDL
Work to do
Higher horizontal resolution: 2x2.5
Tagged tracer simulation: quantify the contributions of different source regions and source types
To interpret discrepancies in terms of errors in individual source terms
