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

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

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


1
INTERCONTINENTAL TRANSPORT OF TROPOSPHERIC OZONE
AND PRECURSORS AT NORTHERN MIDLATITUDES IMPLICAT
IONS FOR SURFACE AIR QUALITY AND GLOBAL CHANGE
  • Daniel J. Jacob, Arlene M. Fiore, Qinbin Li,
    Loretta J. Mickley
  • Atmospheric Chemistry Modeling Group
  • Harvard University

2
OZONE TREND AT EUROPEAN MOUNTAIN SITES,
1870-1990
Marenco et al. 1994
Preindustrial ozone models

3
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
4
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
5
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
6
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

7
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
8
OZONE BACKGROUND OVER U.S. IS GENERALLY DEPLETED
DURING REGIONAL POLLUTION EPISODES due 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
9
RANGE OF ASIAN/EUROPEAN POLLUTION SURFACE OZONE
ENHANCEMENTS OVER THE U.S. IN SUMMER as
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
10
NORTH AMERICAN OZONE OUTFLOW IN SURFACE AIR
(GEOS-CHEM model results for 1997)
APRIL
L
H
L
JULY
H
Li et al. 2001
11
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
12
EFFECT OF NORTH AMERICAN SOURCES ON 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
13
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
14
FORECASTING TRANSATLANTIC TRANSPORT OF NORTH
AMERICAN POLLUTION TO EUROPE FROM THE NORTH
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
15
SURFACE OZONE ENHANCEMENTS CAUSED
BY ANTHROPOGENIC EMISSIONS FROM DIFFERENT
CONTINENTS
GEOS-CHEM model, July 1997
North America
Europe
Asia
Li et al. 2001
16
INTERCONTINENTAL TRANSPORT EXPERIMENT NORTH
AMERICA (INTEX-NA)
Revised white paper, Nov 2001 (H.B. Singh, D.J.
Jacob, L. Pfister)
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

17
INTEGRATION OF AIRCRAFT OBSERVATIONS WITH
SATELLITE DATA AND MODEL INFORMATION IS CRITICAL
TO THE OBJECTIVES OF INTEX-NA
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 snapshots with optimized
information
Chemical and aerosol processes
U.S IMPORT/EXPORT
18
INTEX NOMINAL FLIGHT TRACKS FOR PHASE A (SUMMER)
RL
BG
WL
AZ
DR
BR
NO
HI
DC-8
P-3B
Ozonesonde sites
19
SATELLITE MEASUREMENTS OF TROPOSPHERIC CHEMISTRY
20
MOPITT validation 40N, 132W
0226 at 2005Z double spiral bracketing in time
the MOPITT overpass. Solid stratus deck with
tops at 3.5Kft, otherwise clear sky. Layer at 4-7
km is aged Asian pollution.
DC-8 CO data (Sachse)
21
ATMOSPHERIC COLUMNS OF NO2 AND FORMALDEHYDE
(HCHO) MEASURED FROM GOME BY SOLAR
BACKSCATTER ALLOW MAPPING OF NOx AND HYDROCARBON
EMISSIONS
GOME
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
22
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
23
GOME RETRIEVAL OF TROPOSPHERIC NO2 vs. GEOS-CHEM
SIMULATION (July 1996)
Martin et al. 2001
GEIA emissions scaled to 1996
24
FORMALDEHYDE COLUMNS FROM GOME July 1996 means
Palmer et al. 2001
BIOGENIC ISOPRENE IS THE MAIN SOURCE OF HCHO IN
U.S. IN SUMMER
25
GOME DETECTS THE ISOPRENE VOLCANO IN THE OZARKS
Palmer et al. 2001
26
DEPENDENCE OF GOME HCHO COLUMNS OVER THE OZARKS
ON SURFACE AIR TEMPERATURE
Temperature dependence of isoprene emission (GEIA)
Palmer et al. 2001b
27
MAPPING OF ISOPRENE EMISSIONS FOR JULY 1996 BY
SCALING OF GOME FORMALDEHYDE COLUMNS Palmer et
al., 2001b
GOME
COMPARE TO
GEIA (IGAC inventory)
BEIS2 (official EPA inventory)
28
1750-2000 radiative forcing from tropospheric
ozone is less well constrained than implied by
IPCC 2001 report
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
29
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
30
ONGOING WORK AT HARVARD FOR PHASE I OF OAR/OAQPS
CLIMATE CHANGE MODELING INITIATIVE (Arlene Fiore,
Brendan Field, Daniel Jacob, David Streets)
  • OBJECTIVE 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).
  • APPROACH Conduct global GEOS-CHEM simulations
    with
  • 50 global reductions in emissions
  • realistic future emission scenarios
  • Simulations are for 7/94-12/95 (first 6 mos. for
    initialization) with 4ox5o resolution

31
IMPACTS OF 50 REDUCTIONS IN ANTHROPOGENIC
EMISSIONS
Diagnostic Standard 50 CH4 50 NOx 50 VOC 50 NOx VOC 50 CO 50 All
Median U.S. O3 (ppbv) 51 48 42 50 41 50 38
U.S. grid-square days with 1-5 p.m. O3 gt80 ppbv 37 17 0 26 0 27 0
U.S. grid-square-days with 1-5 p.m. O3 gt60 ppbv 1190 704 96 1059 87 1085 29
Mean U.S.1 background O3 (ppbv) 26 24 23 26 23 26 20
Global tropospheric O3 inventory (Tg) 321 294 300 317 297 317 269
Implied global CH4 concentration (ppbv) 1700 1000 1867 1685 1846 1643 1040
CH4 radiative forcing (W m-2) -- -0.30 0.06 -0.01 0.05 -0.02 -0.28
O3 radiative forcing (W m-2) -- -0.07 -0.06 -0.01 -0.07 -0.01 -0.15
4ox5o GEOS-CHEM model results for JJA 1995
32
GLOBAL MODEL LIMITATIONS FOR SIMULATIONS OF
REGIONAL OZONE POLLUTION Comparison of
GEOS-CHEM (2ox2.5o) and MAQSIP (40x40
km2) spatial statistics of summer means over
eastern U.S. for summer 1995
Statistic MAQSIP AIRS on MAQSIP grid GEOS-CHEM 2 x 2.5 AIRS on GEOS-CHEM grid
Mean (ppbv) 59 55 58 52
Variance (ppbv2) 86 72 47 78
Minimum (ppbv) 18 26 42 26
Maximum (ppbv) 83 72 76 66
Model bias (ppbv) 4 -- 7 --
r2 (model vs. observed) 0.42 -- 0.47 --
33
Varimax rotated EOFs for surface ozone summer
afternoon 1995 AIRS observations on 2ox2.5o grid
- cold fronts
- southeast stagnation
- midwest anortheast
34
Varimax rotated EOFs for surface ozone summer
afternoon 1995 GEOS-CHEM model results
Correlation with EOFs derived from observations
EOF r2 b
1 0.74 -1.0
2 0.91 -1.0
3 0.27 0.5
35
NEXT STEP NESTING OF GEOS-CHEM WITH
MODELS-3 collaboration with 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

36
SOME ISSUES FOR PHASE II OF OAR/OAQPS CLIMATE
CHANGE MODELING INITIATIVE
  • How can we develop an accurate modeling framework
    to address consistently local surface air quality
    and global change issues?
  • Development of nested models
  • 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 does photochemical coupling between aerosols
    and chemistry affect assessments of emission
    changes on surface air quality and global change
    issues?
  • Development of coupled aerosol-chemistry models
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