Harvard Atmospheric Chemistry Modeling Group Leaders: Daniel Jacob, Jennifer Logan

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Harvard Atmospheric Chemistry Modeling
GroupLeaders Daniel Jacob, Jennifer Logan
www-as.harvard.edu/chemistry/trop/index.html
Our group
Some big problems in tropospheric chemistry
Regional air pollution
Trends in emissions and oxidants
Chemistry-climate interactions
Budget of CO2
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Good and bad ozone
Good (UV shield)
Bad (greenhouse gas)
Bad (smog)
NOx NO NO2 nitrogen oxide radicals VOC
(volatile organic compounds) light
hydrocarbons and
substituted organic compounds
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One motivation for our research Large numbers of
people live in regions with unhealthy air.
(millions)
old standard
new
Ozone
Particulate matter (aerosols)
EPA 2005
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How do we investigate problems in atmospheric
chemistry?

• Measurements satellites, aircraft, and
  ground-based instruments.
• Models GEOS-CHEM (3D tropospheric chemistry
  model) and other models.

Mean July 1995 afternoon O3 (ppb) in U.S. surface
air
Model results
Observations
Fiore et al., 2003
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Three parts of todays talk.

• Chemistry-climate interactions (Loretta Mickley,
  Rokjin Park)
• . . .Two major pollutants that have an impact on
  warming  black soot and tropospheric
  ozone.  Both are proven health hazards.  Reducing
  both would not only address climate change, but
  also dramatically improve people's health.
  (George W. Bush, 2001)

• Aircraft measurements (Rynda Hudman)
• Satellite measurements (Colette Heald)

our logo
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Chemistry- climate interaction How do ozone and
black carbon (soot) affect climate?
Soot attenuates incoming sunlight.
outgoing terrestrial radiation (heat)
smog O3
soot
heating
heating
cooling
Ozone absorbs outgoing terrestrial radiation
(like any greenhouse gas)
Soot also absorbs outgoing terrestrial radiation.
Funding NASA Interdisciplinary Science
Investigation, EOS
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Climate can also affect ozone and black carbon
and other particulates a two-way interaction
Hot, stagnant air pollution episode
New England
Number of summer days above EPA ozone threshold,
averaged over northeast U.S.
1988, hottest on record
days
Lin et al. 2001, Funded by EPA
90so F
Will severity or frequency of pollution episodes
change with a changing climate? Answer We dont
know!
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Pollution episodes intensify in model future
atmosphere, even with constant emissions.
Typical pollution episode over 6 days.
Model simulations using pollution tracers with
constant emissions.
2045-2052
cold front
summer
1995-2002
Pollution episodes double in duration in 2050s
due to decreasing frequency of cold fronts
ventilating the eastern and midwestern U.S.
Mickley et al. 2004
Funded by EPA-STAR,
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Life cycle of black carbon (soot) aerosol in the
atmosphere.
CHEMICAL AGING
EMISSION
CLOUD UPTAKE
coating by sulfate or organics
oxidation
How long ?
How much?
Where?
If soot falls on Arctic, it would melt the snow
and decrease albedo (amount of light reflected to
space) warming
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Can soot particles make it to the Arctic? How
much would they decrease the albedo (reflection)
there?
range of possible lifetimes
soot
reflected sunlight
Lifetime
Soot in ice and snow makes surface more
reflective and leads to warming. We calculate
that the warming could be large.
Park et al., 2004 Funded by NASA ACMAP
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ICARTT COORDINATED ATMOSPHERIC CHEMISTRY
CAMPAIGN OVER EASTERN NORTH AMERICA AND NORTH
ATLANTIC IN SUMMER 2004
People at Harvard working on ICARTT analysis
Daniel Jacob, Rynda Hudman, Solene Turquety,
Dylan Millet, Lee Murray, Qinbin Li, Colette
Heald, Yaping Xiao
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NASA DC-8 PAST ATMOSPHERIC CHEMISTRY MISSIONS
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The DC-8 at MidAmerica airport (St. Louis)
NASAs flying laboratory
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NASA DC-8 the inside
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ICARTT COORDINATED ATMOSPHERIC CHEMISTRY
CAMPAIGN OVER EASTERN NORTH AMERICA AND NORTH
ATLANTIC IN SUMMER 2004
International, multi-agency collaboration
Satellite validation
Sources of greenhouse gases
Pollution in Northeastern U.S.
Intercontinental Transport
Aerosol sources, properties
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ICARTT JULY 1-AUGUST 15, 2004
INTEX-NA Flight tracks July 1-Aug 8
NASA INTEX- NA Transcontinental and
intercontinental scale
ITCT-2K4 Flight tracks Jul 1-Aug 15
NOAA ITCT-2K4 Regional source/process study
focused on NE U.S.
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ICARTT GEOS-CHEM FORECASTS ASSISTED IN FLIGHT
PLANNING
Web interface by Lyatt Jaeglé Univ. Washington
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FIRES
NA Pollution
(McMillan, UMBC)
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Inventory of boreal fire emissions for North
America evaluation with satellite observations
for the summer 2004
1) Daily emissions created Comparable to U.S
fossil fuel emissions for July-Aug!

• 2004 fire season in North America
• worst fire season on record in
• Alaska

30 Tg CO
2) Compare GEOS-Chem to MOPITT to evaluate
estimated of strength and height of emissions
Fire season duration and intensity expected to
increase as earth warms!
MOPITT
GEOS-Chem
Pyro-convective cloud from aircraft June 27,
2004 www.cpi.com/remsensing/midatm/smoke.html
S. Turquety et al.
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CORRECTING THE GEOS-Chem OZONE UNDERESTIMATE IN
BACKGROUND AIR IN SUMMER
Observations from ICARTT suggest a factor 4
underestimate of lightning NOx emissions
Simulated Observed
T gt 30,000 oC
NO2 (ppbv)
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LIGHTNING NOx emissions mixed with local
pollution ? LARGE OZONE (OZONE IS A GREENHOUSE
GAS) ENHANCEMENTS
July 10, 1996 storm 4 pm (Barth et al. 2000)
Generic tracer illustrating convective uplift
Thunderstorms lift boundary layer pollution to
high altitudes. These gases combined with
lightning NOx emissions and slow air movement let
air cook ? large ozone enhancement
GEOS-CHEM Ozone 9 km, July 2000
Li et al., 2005
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OTHER CONTINUING ICARTT WORK

• Reactive nitrogen budgets over North America (R.
  Hudman)
• Fire sources and height of injection during
  summer 2004 (S. Turquety)
• Inverse analysis of CO sources (S. Turquety, M.
  Kopacz)
• Biogenic analysis of HCHO using SCHIAMACHY (D.
  Millet)
• Regional Ozone/CO correlations and source
  constraints (L. Murray)
• Using ethane correlations to deduce sources (Y.
  Xiao)
• Organic Carbon in the free troposphere (C.
  Heald)

INTEX- B March April 2006
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SATELLITE OBSERVATIONS OF TROPOSPHERIC
COMPOSITION
Randall V. Martin1, Paul I. Palmer2, Dorian S.
Abbot, Tzung-May Fu, Colette L. Heald, Yang Liu,
Lin Zhang, Parvadha Suntharaligham
Work supported by NASA, EPA, EPRI
1 now at Dalhousie University 2 now at Leeds
University
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OBSERVATION SYSTEM FOR TROPOSPHERIC COMPOSITION
very sparse at present satellites will change
this
satellites
Ozone Layer
Stratosphere
8-12 km
Troposphere
aircraft campaigns
Greenhouse Gases and Pollutants
sondes
Emissions
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TROPOSPHERIC COMPOSITION FROM SPACEplatforms,
instruments, species

• Improving estimates of global emission sources
• Long-range transport of pollution
• Air quality and chemical data assimilation

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SATELLITE (GOME) OBSERVATIONS OF NITROGEN
DIOXIDEcombustion gas, major smog precursor
1996
Exploit observations to improve estimates of
emissions
Martin et al. 2002
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HIGHER SPATIAL RESOLUTION FROM SCIAMACHY
SCIAMACHY data May-Oct 2004 (R.V. Martin,
submitted)
SCIAMACHY 60x30 km2 GOME 320x40 km2
detection limit
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SATELLITE (GOME) OBSERVATIONS OF
FORMALDEHYDEdominant sources from vegetation,
biomass fires
2.5x1016 molecules cm-2
2
1.5
detection limit
1
0.5
0
-0.5
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SEASONAL VARIATION OF FORMALDEHYDE FROM
GOMEcompared to a global model
Agreement in general pattern, regional
discrepancies demonstrate potential of GOME for
improving understanding of biogenic emissions
SATELLITE MODEL
SATELLITE MODEL
JUL
MAR
AUG
APR
SEP
MAY
OCT
JUN
Abbot et al. 2003
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FORMALDEHYDE OVER EAST ASIA (1996-2001)
Satellite Model Satellite
Model Satellite Model

1016 molecules cm-2
Relationship to biogenic emissions far more
complex than for N. America biomass burning,
anthropogenic sources, direct emission all ALSO
contribute
Tzung-May Fu , in prep.
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MAPPING SURFACE PARTICULATE MATTER CONCENTRATIONS
USING SATELLITE DATA (MISR)
Liu et al. 2004
Satellite observations of aerosol optical depth
Satellite observes aerosols through entire
atmosphere
But for air quality we care about surface!
Derived Surface Particulate Matter
Surface Observations
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U.S. VISIBILITY IMPAIRMENT BY ASIAN DUST STORMS
clear day
April 16, 2001 Asian dust!
Glen Canyon, Arizona
anthropogenic pollution is transported together
with the dust
Aerosol optical depth (AOD) Carbon
monoxide (CO) MODIS satellite data model (dust)
model (sulfate) MOPITT satellite data
satellite data
satellite data
Colette Heald, in prep.
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INTEGRATION OF AIRCRAFT, SATELLITE AND MODEL TO
QUANTIFY CARBON MONOXIDE SOURCES FROM ASIA
AIRCRAFT CO DATA (TRACE-P)
Fossil and biofuel
Daily biomass burning
A PRIORI EMISSIONS
chemical forecasts
MODEL (GEOS-CHEM)
top-down constraints
validation
INVERSE ANALYSIS

• CONCLUSIONS
• A priori Chinese emissions too low by 40
• (small industrial coal facilities)
• A priori SE Asian and Indian emissions (biomass
  burning) too high by 55
• Satellite observations have more information
  than aircraft for constraining Asian sources

SATELLITE CO (MOPITT)
Heald et al. 2004
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MULTI-SPECIES OBSERVATIONS FROM TES
Tropospheric Emission Spectrometer (TES) launched
aboard EOS-Aqua 2004
Ozone Carbon
Monoxide
Satellite (TES)
Model (GEOS-Chem)
November 2004, 500hPa
Lin Zhang, in progress
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UNDERSTANDING THE ORIGIN OF ATMOSPHERIC CARBON
DIOXIDE
Reduced carbon is an important source of
atmospheric CO2. Essential that we understand
the global distribution of CO2 sources/sinks
Particularly with launch of Orbiting Carbon
Observatory (2008)
1.1 Pg C/yr
OTHER CARBON CO, CH4, NMVOCs
ATMOSPHERIC CO2
OXIDATION
(Increasing 3.2 PgC/yr)
6.3 PgC/yr
2.2 PgC/yr
-2.4 PgC/yr
FOSSIL
BIOMASS BURNING
OCEANS
BIOSPHERE
AGRICULTURE
Suntharaligham et al. 2005
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LOOKING TOWARD THE FUTUREGEOSTATIONARY AND L1
MISSION CONCEPTS
GEO
L1
NRC Decadal Survey Proposal Janus

• Continuous mapping of tropospheric columns of O3,
  aerosols, CO, CH2O, NO2, SO2
• Continental-scale for GEO, full sunlit disk for
  L1
• km-scale resolution