FACTORS CONTROLLING TROPOSPHERIC OZONE AND ITS COUPLING FROM REGIONAL TO GLOBAL SCALES

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FACTORS CONTROLLING TROPOSPHERIC OZONE AND ITS
COUPLING FROM REGIONAL TO GLOBAL SCALES
Daniel J. Jacob Harvard University
with support from NASA, NOAA, EPA, EPRI
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GLOBAL BUDGET OF TROPOSPHERIC OZONE
Global sources and sinks, Tg O3 yr-1 (GEOS-CHEM)
O2
hn
O3
STRATOSPHERE
8-18 km
TROPOSPHERE
hn
NO2
NO
O3
hn, H2O
OH
HO2
H2O2
Deposition
CO, VOC
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TREND IN TROPOSPHERIC OZONE BACKGROUNDAT
NORTHERN MIDLATITUDES
Observations from European mountain sites
Marenco et al., 1994
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THIS OZONE BACKGROUND IS A LARGE INCREMENT
TOWARDS VIOLATION OF AIR QUALITY STANDARDS
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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GLOBAL TRANSPORT OF TROPOSPHERIC OZONEAROUND THE
NORTHERN MIDLATITUDES POLLUTION BELT
Ozonesonde and MOZAIC observations at 400 hPa,
July 1997
Li et al. 2001
How does this intercontinental transport of ozone
contribute to regional air quality issues?
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SUMMER 1995 MEAN AFTERNOON OZONE IN SURFACE AIR
Fiore et al. 2002a
AIRS observations
GEOS-CHEM model (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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SURFACE OZONE ENHANCEMENTS OVER U.S. IN
SUMMERDUE TO ASIAN EUROPEAN ANTHROPOGENIC
EMISSIONSGlobal 3-D model results (GEOS-CHEM)
sampled for ensemble of summer days over the U.S.
Fiore et al. 2002a
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NORTH AMERICAN OZONE OUTFLOW IN SURFACE AIR
(GEOS-CHEM model results for 1997)
L
APRIL
H
L
JULY
H
Li et al. 2002a
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TRANSPORT OF U.S. OZONE POLLUTIONTO BERMUDA IN
SPRING
Observations (S. Oltmans)
GEOS-CHEM model
(S. Oltmans)
Most of surface ozone over Bermuda in spring
originates from the U.S. stratosphere
contributes less than 5 ppbv
Li et al. 2002b
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OZONE AT MACE HEAD, IRELAND (Mar-Aug 97)
North American pollution events enhance ozone by
5-15 ppbv
Li et al. 2002b
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TRANSPORT OF U.S. POLLUTION TO EUROPECORRELATION
WITH THE NAO INDEX
NAO index normalized surface P anomaly between
Iceland and Azores
North Atlantic Oscillation (NAO) Index
North American ozone pollution enhancement At
Mace Head, Ireland (GEOS-CHEM model)
r 0.57
Li et al. 2002a
Greenhouse warming a NAO index shift a change
in transatlantic

transport of pollution
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SPRINGTIME ENHANCEMENT OF OZONE OVER ASIADUE TO
EUROPEAN ANTHROPOGENIC EMISSIONS
GEOS-CHEM model results at 900 hPa, March-May 1996
Liu et al. 2002
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Combined effects of future anthropogenic emission
trendson U.S. ozone air quality and on global
climate
Ozone pollution
Fiore et al. 2002b
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NOx EMISSIONS (Tg N yr-1) TO TROPOSPHERE
STRATOSPHERE 0.2
LIGHTNING 5.8
FOSSIL FUEL 23.1
SOILS 5.1
BIOMASS BURNING 5.2
BIOFUEL 2.2
AIRCRAFT 0.5
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OZONE POLLUTION IN THE UNITED STATES
90th percentiles of summer afternoon (1-5 pm)
surface ozone concentrations (ppbv), 1980-1995
Fiore et al. 1998