Joint UNEP F&T and TF HTAP meeting, Rome 2008
EMEP/MSC-E Hg modeling system:application to TF HTAP intercomparison study
Oleg Travnikov
EMEP/MSC-E
Joint UNEP F&T and TF HTAP meeting, Rome 2008
Outline
EMEP/MSC-E Hg model description
TF HTAP Hg models intercomparison study
Modeling Hg atmospheric dispersion in the Northern Hemisphere
Intercomparison of modeling results
Major uncertainty sources of Hg modeling on a global scale
Joint UNEP F&T and TF HTAP meeting, Rome 2008
Hemispheric model (MSCE-HM-Hem)
Coverage – Northern Hemisphere
Resolution – 2.5° 2.5°Global model (MSCE-HM-Glob)
Coverage – global
Resolution – 1° 1°
EMEP/MSC-E Hg modeling system
Regional model (MSCE-HM)
Coverage – EMEP region
Resolution – 50 50 km2
Joint UNEP F&T and TF HTAP meeting, Rome 2008
Model processesAtmospheric dispersion:
Eulerian framework
Met input – ECMWF, NCEP/DOE
Met driver – SDA, GEMCVC
Atmospheric chemistry:
Gas-phase oxidation by O3, OH, Cl2
Aqueous-phase oxidation by O3, OH,
HOCl, OCL-
Aqueous-phase reduction by SO3=
No halogen chemistry in MBL
No explicit treatment of AMDE
Air-surface exchange:
Dry and wet deposition
Prescribed evasion fluxes from land
and ocean
No explicit treatment of Hg cycling
between media (atmosphere, ocean …)
Joint UNEP F&T and TF HTAP meeting, Rome 2008
TF HTAP intercomparison study
Aims of the TF HTAP model intercomparison study:
Assessment of intercontinental source-receptor
relationships
Evaluation of current models variability and uncertainties
Guidance of future model developments
Participants of Hg hemispheric/global models comparison:
MSCE-HM (EMEP/MSC-E)
GRAHM (Environment Canada, Canada)
ECHMERIT (CNR-IIA, Italy)
GEOS-Chem (Harvard University, USA)
CTM-Hg (AER, USA)
Joint UNEP F&T and TF HTAP meeting, Rome 2008
TF HTAP intercomparison study
Simulation experiment conditions:
Reference year 2001
Baseline simulation with all emission sources
Perturbation runs with 20% emission reduction in four
source regions (Europe & N. Africa, North America, East
Asia, South Asia)
North AmericaEurope & N.Africa
South Asia
East Asia
Joint UNEP F&T and TF HTAP meeting, Rome 2008
Hg emissions data
Evasion from land and ocean
Based on Lamborg et al., 2002(ca. 1800 t/y)
East Asia
839 t/y (38%)
South Asia
178 t/y (8%)
Europe
273 t/y (12%)North America
144 t/y (7%)
Other
756 t/y (35%)
Anthropogenic Hg emissions for 2000 (Pacyna et al., 2006)
North America
Europe & N.Africa
South Asia
East Asia
Joint UNEP F&T and TF HTAP meeting, Rome 2008
Evaluation of modeling results
- air concentrations- wet deposition flux
TGM concentration Hg concentration in prec.
0 1 2 3 40
1
2
3
4
Cmod
= 0.93 Cobs
Rcorr
= 0.69
M
odel, n
g/m
3
Observed, ng/m3
0 5 10 15 20 25 300
5
10
15
20
25
30
Cmod
= 1.18 Cobs
Rcorr
= 0.3
Mo
de
l, n
g/L
Observed, ng/L
Long-term simulation of Hg dispersion in the Northern Hemisphere (1990-2004)
Spatial variation (annual means)
2
1/2
2
1/2
Joint UNEP F&T and TF HTAP meeting, Rome 2008
- air concentrations- wet deposition flux
Evaluation of modeling resultsLong-term simulation of Hg dispersion in the Northern
Hemisphere (1990-2004)
Temporal variation (monthly means)
NO99 FL05
Correlation 0.41 0.40
Bias -10% -3%
Monthly statistics
0
10
20
30
40
50
янв 9
0
ию
л 9
0
янв 9
1
ию
л 9
1
янв 9
2
ию
л 9
2
янв 9
3
ию
л 9
3
янв 9
4
ию
л 9
4
янв 9
5
ию
л 9
5
янв 9
6
ию
л 9
6
янв 9
7
ию
л 9
7
янв 9
8
ию
л 9
8
янв 9
9
ию
л 9
9
янв 0
0
ию
л 0
0
янв 0
1
ию
л 0
1
янв 0
2
ию
л 0
2
янв 0
3
ию
л 0
3
янв 0
4
ию
л 0
4
Conc. in
pre
cip
itation, ng/L
Model
ObservedHg in precipitation, NO99 (Norway)
0
10
20
30
40
50
янв 9
0
ию
л 9
0
янв 9
1
ию
л 9
1
янв 9
2
ию
л 9
2
янв 9
3
ию
л 9
3
янв 9
4
ию
л 9
4
янв 9
5
ию
л 9
5
янв 9
6
ию
л 9
6
янв 9
7
ию
л 9
7
янв 9
8
ию
л 9
8
янв 9
9
ию
л 9
9
янв 0
0
ию
л 0
0
янв 0
1
ию
л 0
1
янв 0
2
ию
л 0
2
янв 0
3
ию
л 0
3
янв 0
4
ию
л 0
4
Conc. in
pre
cip
itation, ng/L
Model
Observed
Hg in precipitation, FL05 (USA)
Joint UNEP F&T and TF HTAP meeting, Rome 2008
Baseline simulation
Total deposition of Hg in the Northern Hemisphere in 2001 Average deposition flux
0
5
10
15
20
Europ
e & N
.Afri
ca
Nor
th A
mer
ica
East A
sia
South
Asia
Arctic
Nor
th A
tlant
ic
Nor
th P
acific
Depositio
n flu
x, g/k
m2/y
Evasion North America
Europe & N.Africa South Asia
East Asia Other
Joint UNEP F&T and TF HTAP meeting, Rome 2008
Perturbation runs
Decrease of Hg deposition in the Northern Hemisphere due to 20% emission reduction
in Europe in North America
Joint UNEP F&T and TF HTAP meeting, Rome 2008
Perturbation runs
Decrease of Hg deposition in the Northern Hemisphere due to 20% emission reduction
in East Asia in South Asia
Joint UNEP F&T and TF HTAP meeting, Rome 2008
Seasonal variability
Spring
Summer Fall
Winter
Decrease of Hg deposition in the Northern Hemisphere due to 20% emission reduction in Europe
Joint UNEP F&T and TF HTAP meeting, Rome 2008
Response of Hg deposition to emission reduction
Receptors Deposition decrease due to 20% emission reduction in different source regions
0
5
10
15
20
Europe&
N.Africa
North
America
East
Asia
South
Asia
Arctic North
Atlantic
North
Pacific
Receptors
Depositi
on d
ecre
ase, %
Europe & N.Africa North America
East Asia South Asia
Joint UNEP F&T and TF HTAP meeting, Rome 2008
Models intercomparison
0
5
10
15
20
Europe&
N.Africa
North
America
East Asia South Asia
Receptors
Depositio
n d
ecre
ase, %
Europe & N.Africa North America
East Asia South Asia
0
5
10
15
20
Europe&
N.Africa
North
America
East Asia South Asia
Receptors
Depositi
on d
ecre
ase, %
Europe & N.Africa North America
East Asia South Asia
0
5
10
15
20
Europe&
N.Africa
North
America
East Asia South Asia
Receptors
Depositi
on d
ecre
ase, %
Europe & N.Africa North America
East Asia South Asia
MSCE-HM GRAHM GEOS-Chem
Emissions (t/y) MSCE-HM GRAHM GEOS-Chem CTM-Hg
Anthropogenic 2200 (55%) 3400 (37%) 2200 (34%)
Natural 1800 (45%) 5830 (63%) 4340 (66%)
Total 4000 9230 6540
0
5
10
15
20
Europe&
N.Africa
North
America
East Asia South Asia
Receptors
Depositi
on d
ecre
ase, %
Europe & N.Africa North America
East Asia South Asia
CTM-Hg
Global Hg emissions used by the models
Joint UNEP F&T and TF HTAP meeting, Rome 2008
Preliminary conclusions
In general models agree in assessment of Hg deposition response to emission reduction
Hg depositions to most receptor regions (except North America) are the most sensitive to reduction of own emissions
The largest deposition response is predicted for East Asia and the smallest for North America
Total sensitivity of Hg deposition to emission reduction varies between the models and depends on relative contribution of anthropogenic emission
Joint UNEP F&T and TF HTAP meeting, Rome 2008
Sources of modeling uncertainty
Anthropogenic (incl. speciation) and natural emissions
Ignoring Hg dispersion and cycling betweendifferent media (atmosphere, ocean, soil etc.)
Hg chemistry in atmosphere and other media (reaction rates, halogen chemistry in MBL, AMDE, photoreduction in snow and seawater etc.)
Lack of measurements to evaluate the models
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