INTERCONTINENTAL TRANSPORT OF TROPOSPHERIC OZONE AND PRECURSORS AT NORTHERN MIDLATITUDES: IMPLICATIONS FOR SURFACE AIR QUALITY AND GLOBAL CHANGE

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INTERCONTINENTAL TRANSPORT OF TROPOSPHERIC OZONE
AND PRECURSORS AT NORTHERN MIDLATITUDESIMPLICAT
IONS FOR SURFACE AIR QUALITY AND GLOBAL CHANGE

• Daniel J. Jacob, Arlene M. Fiore, Qinbin Li,
  Randall V. Martin, Loretta J. Mickley, Paul I.
  Palmer, Rokjin Park

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OZONE TREND AT EUROPEAN MOUNTAIN SITES, 1870-1990
Marenco et al. 1994
Preindustrial ozone models

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1750-2000 radiative forcing from tropospheric
ozoneis less well constrained than implied by
IPCC 2001 report (and could be greatly
underestimated)
Global simulation of late 19th century ozone
observations with the GISS GCM
Standard model DF 0.44 W m-2 Adjusted
model (lightning and soil NOx decreased, biogenic
hydrocarbons increased) DF 0.80 W m-2
Mickley et al., 2001
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GLOBAL MEAN TEMPERATURE CHANGE SINCE 1750 DRIVEN
BY MODEL TROPOSPHERIC OZONE CHANGE
and compared to temperature changes from equal
radiative forcings (0.45 W m-2) by uniformly
mixed ozone and CO2 (GISS GCM 2)
Compared to an equivalent CO2 radiative forcing,
tropospheric ozone gives less tropospheric
warming and more stratospheric cooling
CO2
Uniform ozone
Ozone
Loretta Mickley, In preparation
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SURFACE OZONE IN U.S. INCLUDES A 20-40 ppbv
BACKGROUND THAT HAS INCREASED BY 3 ppbv OVER
THE PAST 20 YEARS
8-h daily maximum ozone probability distribution
at rural U.S. sites Lin et al., 2000
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THIS OZONE BACKGROUND IS A SIZABLE INCREMENT
TOWARDS VIOLATION OF U.S. AIR QUALITY
STANDARDS(even more so in Europe!)
Europe (8-h avg.)
Europe (seasonal)
U.S. (8-h avg.)
U.S. (1-h avg.)
0 20 40
60 80 100
120 ppbv
preindustrial
present background
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Simulated increase in mean U.S. surface ozone
(ppbv) from tripling of Asian emissions (1985 to
2015)with other emissions held constant
Enough to offset the benefits of 25 reductions
in domestic emissions!
Jacob et al. 1999
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GEOS-CHEM global model of tropospheric
chemistry(www-as.harvard.edu/chemistry/trop/geos)

• assimilated meteorological data from NASA DAO,
  1988-2001
• 1ox1o- 4ox5o horizontal resolution, 20-48 layers
  in vertical
• used by groups at Harvard, Duke, U. Washington,
  Rutgers, JPL, BNL, EPFL, Toulouse, Aquila
  standard versions and benchmarks maintained at
  Harvard
• RECENT AND CURRENT APPLICATIONS
• Tropospheric ozone global budget, Asian
  outflow, U.S. air quality, Middle East,
  transatlantic transport, tropics (TOMS),
  interannual variability, trends
• Carbon monoxide global and regional budgets,
  interannual variability
• Aerosols sulfate-organics-dust-sea salt
• Stratospheric ozone coupling with troposphere
• Carbon dioxide source/sink information from
  correlations with chemical tracers
• Organics budgets of hydrocarbons, oxygenated
  organics, nitriles, methyl halides
• Satellite retrievals, inversions, chemical data
  assimilation CO, CO2, ozone, formaldehyde, NO2
• Chemical forecasting TRACE-P

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SUMMER 1995 AFTERNOON OZONE IN SURFACE AIR
Fiore et al. 2001
AIRS observations
GEOS-CHEM (r2 0.4, bias3 ppbv)
Background ozone produced outside the North
American boundary layer contributes 15-35 ppbv
to mean surface air concentrations in the model
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OZONE BACKGROUND OVER U.S. IS GENERALLY DEPLETED
DURING REGIONAL POLLUTION EPISODESdue to
deposition and chemical loss under stagnant
conditions
Observed (J.W. Munger) model (GEOS-CHEM) model
background
O3 vs. (NOy-NOx) At Harvard Forest,
Massachusetts
Background (clean conditions)
Background (pollution episodes)
Fiore et al. 2001
Pollution coordinate
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RANGE OF ASIAN/EUROPEAN POLLUTION SURFACE OZONE
ENHANCEMENTS OVER THE U.S. IN SUMMERas
determined from a simulation with these emissions
shut off
Subsidence of Asian pollution local production
Max Asian/European pollution enhancements (up to
14 ppbv) occur at intermediate ozone levels
(50-70 ppbv)
stagnation
tropical air
MAJOR CONCERN IF OZONE STANDARD WERE TO DECREASE!
Fiore et al. 2001
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NORTH AMERICAN OZONE OUTFLOW IN SURFACE AIR
(GEOS-CHEM model results for 1997)
APRIL
L
H
L
JULY
H
Li et al. 2001
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ORIGIN OF SURFACE OZONE AT BERMUDA IN SPRING
(S. Oltmans)
Production over U.S. is the dominant source of
ozone at Bermuda stratosphere contributes less
than 5 ppbv
Li et al. 2001
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OZONE DATA AT MACE HEAD, IRELAND
Model vs. observed stats, 1993-1997
Time series, Mar-Aug 1997
GEOS-CHEM model
N.America pollution events in model
Li et al. 2001
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EFFECT OF NORTH AMERICAN SOURCESON VIOLATIONS OF
EUROPEAN AIR QUALITY STANDARD (55 ppbv, 8-h
average)
GEOS-CHEM model results, summer 1997
Number of violation days (out of 92)
of violation days that would not have been in
absence of N.American emissions
Li et al. 2001
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FORECASTING TRANSATLANTIC TRANSPORT OF NORTH
AMERICAN POLLUTION TO EUROPE WITH THENORTH
ATLANTIC OSCILLATION (NAO) INDEX
NAO index normalized surface P anomaly between
Iceland and Azores
NAO Index
North American ozone pollution enhancement At
Mace Head, Ireland (GEOS-CHEM model)
r 0.57
Li et al. 2001
Greenhouse warming a NAO index shift a change
in transatlantic

transport of pollution
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SURFACE OZONE ENHANCEMENTS CAUSED
BYANTHROPOGENIC EMISSIONS FROM DIFFERENT
CONTINENTS
GEOS-CHEM model, July 1997
North America
Europe
Asia
Li et al. 2001
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QUANTIFYING INTERCONTINENTAL TRANSPORTTHROUGH
INTEGRATION OF OBSERVATIONS AND MODELS
SATELLITE OBSERVATIONS Global and continuous but
few species, low resolution
Source/sink inventories
3-D CHEMICAL TRACER MODELS
SURFACE OBSERVATIONS high resolution but
spatially limited
Assimilated meteorological data
AIRCRAFT OBSERVATIONS High resolution, targeted
flights provide critical snapshots for model
testing
Chemical and aerosol processes
INTERCONTINENTAL TRANSPORT CONCENTRATIONS,
FLUXES, BUDGETS
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INTERCONTINENTAL TRANSPORT EXPERIMENT NORTH
AMERICA (INTEX-NA)
A NASA Global Tropospheric Experiment (GTE)
mission
OBJECTIVES

• To quantify the North American import and export
  of
• (1) atmospheric oxidants and their precursors,
  (2) aerosols and their precursors, (3) long-lived
  greenhouse gases
• To relate this import/export to surface
  sources/sinks and to continental boundary layer
  chemistry

TWO AIRCRAFT NASA DC-8 and P-3

• TWO PHASES
• Summer 2004
• active photochemistry, biosphere
• aerosol radiative forcing
• carbon uptake
• Spring 2006
• maximum Asian inflow
• contrast with summer

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INTEX NOMINAL FLIGHT TRACKS FOR PHASE A (SUMMER)
RL
BG
WL
AZ
DR
BR
NO
HI
DC-8
P-3B
Ozonesonde sites
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ATMOSPHERIC COLUMNS OF NO2 AND FORMALDEHYDE
(HCHO) MEASURED FROM GOME BY SOLAR
BACKSCATTERALLOW MAPPING OF NOx AND HYDROCARBON
EMISSIONS
GOME SATELLITE INSTRUMENT
Tropospheric NO2 column ENOx Tropospheric HCHO
column ENMHC
2 km
hn (420 nm)
hn (340 nm)
BOUNDARY LAYER
NO2
NO
HCHO
OH
CO
hours
O3, RO2
hours
NMHC
1 day
HNO3
Emission
Emission
Deposition
NITROGEN OXIDES (NOx)
NON-METHANE HYDROCARBONS
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CAN WE USE GOME TO ESTIMATE NOx EMISSIONS?TEST
IN U.S. WHERE GOOD A PRIORI EXISTS
Comparison of GOME retrieval (July 1996) to
GEOS-CHEM model fields using EPA emission
inventory for NOx
GOME
GEOS-CHEM (EPA emissions)
BIAS 3 R 0.79
Martin et al. 2001
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GOME RETRIEVAL OF TROPOSPHERIC NO2vs. GEOS-CHEM
SIMULATION (July 1996)
Martin et al. 2001
GEIA emissions scaled to 1996
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FORMALDEHYDE COLUMNS FROM GOMEJuly 1996 means
Palmer et al. 2001
BIOGENIC ISOPRENE IS THE MAIN SOURCE OF HCHO IN
U.S. IN SUMMER
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GOME DETECTS THE ISOPRENE VOLCANO IN THE OZARKS
Palmer et al. 2001
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CORRELATION WITH SURFACE TEMPERATUREOF GOME HCHO
COLUMNS OVER THE OZARKS
Temperature dependence of isoprene emission (GEIA)
Palmer et al. 2001
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MAPPING OF ISOPRENE EMISSIONS FOR JULY 1996 BY
SCALING OF GOME FORMALDEHYDE COLUMNS Palmer et
al., 2001
GOME
COMPARE TO
GEIA (IGAC inventory)
BEIS2
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ONGOING WORK AT HARVARD FOR PHASE I OF OAR/OAQPS
CLIMATE CHANGE MODELING INITIATIVE(Arlene Fiore,
Rokjin Park, Brendan Field, Daniel Jacob)

• OBJECTIVES
• Determine the global impacts of future changes
  in anthropogenic emissions on
• surface ozone in N. America, Europe, and Asia
• surface ozone background
• tropospheric oxidizing capacity
• radiative forcing (CH4 and O3).
• Develop coupled ozone-aerosol simulation
  capability in GEOS-CHEM for nesting with
  CMAQ/Models-3

• APPROACH
• Conduct global GEOS-CHEM simulations with
• 50 global reductions in emissions
• realistic future emission scenarios (Streets)
• Implement GEOS aerosol simulation from Mian Chin
  (NASA/GSFC) into GEOS-CHEM model

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IMPACTS OF 50 REDUCTIONS IN ANTHROPOGENIC
EMISSIONS
Simulations are for 7/94-12/95 (first 6 mos. for
initialization) with 4ox5o resolution
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NEXT STEP NESTING OF GEOS-CHEM WITH MODELS-3in
collaboration with EPA/OAQPS and ORD

• One-way nesting use GEOS-CHEM global model
  fields as time-dependent boundary conditions for
  simulation of ozone, aerosols, and their
  precursors in Models-3
• First application Texas 2000 field campaign
• Two-way nesting develop better simulation of
  regional effects on global atmospheric chemistry
  including intercontinental transport and
  radiative forcing

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SOME PRIORITY QUESTIONS FOR PHASE II OF
OAR/OAQPS CLIMATE CHANGE MODELING INITIATIVE

• How can we develop an integrated modeling
  framework to assess the effects of specific
  perturbations (e.g., anthropogenic emissions) on
  local surface air quality and global change in a
  consistent manner?
• Development of nested aerosol-chemistry models
• How can we design an observational strategy to
  evaluate model assessments of intercontinental
  transport?
• Use models to define the observations needed to
  test them
• How can we extract information from satellite
  observations on intercontinental transport of
  pollution?
• Integration with in situ observations and models,
  development of inverse modeling tools
• How can we better understand the climate forcings
  of ozone and aerosols?
• Development of coupled aerosol-chemistry-climate
  models