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Urban Air Pollution, Tropospheric Chemistry, and Climate Change:
An Integrated Modeling Study
Chien WangMIT
Linking Urban Pollution, Tropospheric Chemistry and Climate Change
� Impact of urban air pollution on global tropospheric chemistry and climate (e.g., tropospheric O3 and NOxbudgets, radiative forcing by O3 and aerosols);
� Impact of future climate change on urban air pollution and tropospheric chemistry (e.g., effects of clouds, UV, precipitation, H2O, and temperature on reaction rates);
� Interaction between urban/tropospheric chemistry and climate under various emissions policies;
� Anthropogenic aerosols' impact on human health;� Impact of air pollution and climate change on natural
ecosystems
Integrated Modelling Study� Climate-chemistry interactions require models with integrated
components of atmosphere, ocean, tropospheric chemistry, emissions (policy and non-policy), and ecosystem;
� Integration time: ≥≥≥≥ 10 years for tropospheric chemistry studies (primarily due to CH4 and O3 simulation as well as aerosol forcing assessment), ≥≥≥≥ 100 years for tropospheric chemistry and climate interaction studies;
� Subgrid scale nature of urban and fast tropospheric chemistry aswell as lightning production of certain chemical species in current global models with resolution coarser than ~100 km requires adequate parameterizations for relevant processes;
� Data base (measurement and emissions);� Computational efficiency (parallel, esp. distributed memory
computing)
Atmospheric Chemistry ModelAtmospheric Chemistry Model
25 Chemical species25 Chemical species4 Aerosol groups4 Aerosol groups
Advection, convection, and mixingAdvection, convection, and mixingGaseous and aqueous reactionsGaseous and aqueous reactions
Wet and dry depositionWet and dry deposition Climate ModelClimate ModelMIT 2DLO, MIT 2DLO,
NCAR CCM/CSM, MIT AIM/OGCMNCAR CCM/CSM, MIT AIM/OGCM
Circulation and state of atmosphereCirculation and state of atmosphereLand and oceanLand and ocean
Clouds and PrecipitationClouds and PrecipitationRadiationRadiation
Urban Air Pollution Model Urban Air Pollution Model Natural Emission ModelNatural Emission Model
Ocean Carbon ModelOcean Carbon ModelEPPA and Emission PreprocessorEPPA and Emission Preprocessor
Terrestrial Ecosystem ModelTerrestrial Ecosystem Model
NPP, NEP, soil carbon poolNPP, NEP, soil carbon pool
Concentrations Concentrations of chemicalsof chemicals
Winds, T, HWinds, T, H22O,O,precipitation precipitation
and radiative fluxesand radiative fluxes
MIT Interactive Chemistry-Climate Model
Urban Air Pollution Model and Global Chemistry Model
Projected Future Increases of Emissions (Emissions/Emissions of 1995; MIT EPPA)
0.5
1
1.5
2
2.5
3
3.5
4
1995 2010 2025 2040 2055 2070 2085 2100YearYearYearYear
Ra
tio
sR
ati
os
Ra
tio
sR
ati
os
SO2
BC
OC
South Pole (102W 87S)
0.00
0.50
1.00
1.50
2.00
2.50
3.00
3.50
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Month
Surfa
ce B
C in
ng/
M^3
OBS 1989Model
Barrow (40W 70N)
0.00
20.00
40.00
60.00
80.00
100.00
120.00
140.00
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Month
Surfa
ce B
C in
ng/
M^3
OBS 1989Model
Mauna Loa (155.4W 19.3N)
0.00
5.00
10.00
15.00
20.00
25.00
30.00
35.00
40.00
45.00
50.00
1 2 3 4 5 6 7 8 9 10 11 12
Month
Sur
face
BC
in n
g/M
^3
OBS 1992Model
Amsterdam Island (77.3E 37.5S)
0.00
2.00
4.00
6.00
8.00
10.00
12.00
14.00
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Month
Surfa
ce B
C in
ng/
M^3
OBS 1991Model
Summary� Integrated models are needed for linking urban air pollution,
tropospheric chemistry, and climate; required integration time varies from 10 - 100 years depending on the given topics;
� Adequate parameterizations of urban scale air chemistry and other subgrid scale chemical processes in global models are critical to modeling results;
� Future black carbon emissions may increase according to the MIT EPPA Model;
� Modeled radiative forcing of aerosols is highly uncertain, multiple year integrations with uncertainty analyses are needed for assessment;
� Policy and health issues related to urban air pollution and anthropogenic emissions of aerosols need to be explored and inclusion of interaction between tropospheric chemistry and climate change is important.
