ATMOSPHERIC CHEMISTRY: FROM AIR POLLUTION TO GLOBAL CHANGE AND BACK Daniel J. Jacob.
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Transcript of ATMOSPHERIC CHEMISTRY: FROM AIR POLLUTION TO GLOBAL CHANGE AND BACK Daniel J. Jacob.
ATMOSPHERIC CHEMISTRY:ATMOSPHERIC CHEMISTRY:FROM AIR POLLUTION TO GLOBAL CHANGE AND BACKFROM AIR POLLUTION TO GLOBAL CHANGE AND BACK
Daniel J. Jacob
NUMBER OF PEOPLE LIVING IN U.S. COUNTIES NUMBER OF PEOPLE LIVING IN U.S. COUNTIES VIOLATING NATIONAL AIR QUALITY STANDARDS, 1999VIOLATING NATIONAL AIR QUALITY STANDARDS, 1999
EPA [2001]
124 ppbv84 ppbv
Carbon monoxide (CO)
Lead
Nitrogen dioxide
Ozone (O3)
Particles < 10 m(PM10)
Particles < 2.5 m(PM2.5)
Sulfur dioxide(SO2)
Any pollutant
MEAN NUMBER OF SUMMER DAYS (1980-1998) MEAN NUMBER OF SUMMER DAYS (1980-1998) EXCEEDING THE U.S. OZONE AIR QUALITY STANDARD EXCEEDING THE U.S. OZONE AIR QUALITY STANDARD
(84 ppbv, 8-hour average)(84 ppbv, 8-hour average)
EPA/AIRS data [Lin et al., 2001]
SOURCES OF TROPOSPHERIC OZONESOURCES OF TROPOSPHERIC OZONE
?
?
?
Fires Biosphere Humanactivity
Lightning
Ocean physicschemistrybiology
Nitrogen oxides (NOx) CO, Hydrocarbons
hOzone (O3)
h, H2OHydroxyl (OH)
The Pacman of the atmosphere!
Complex non-linear chemistry
Tropopause (8-18 km)Stratospheric ozone
STRATOSPHERE
TROPOSPHERE
O2 + h
LARGE-SCALE POLLUTION IN THE TROPICS:LARGE-SCALE POLLUTION IN THE TROPICS:BIOMASS BURNINGBIOMASS BURNING
•
R. Husar
TRANSPACIFIC TRANSPORT OF ASIAN DUSTTRANSPACIFIC TRANSPORT OF ASIAN DUST
April 1998 event
CLIMATE FORCING BY AIR POLLUTANTSCLIMATE FORCING BY AIR POLLUTANTS
GLOBAL RADIATIVE FORCING OF CLIMATE, 1750-present [IPCC, 2001]GLOBAL RADIATIVE FORCING OF CLIMATE, 1750-present [IPCC, 2001]
POLLUTANT-RELATED
BLACK CARBON: A MAJOR “GREENHOUSE” AEROSOLBLACK CARBON: A MAJOR “GREENHOUSE” AEROSOL
Chin et al. [2000]
DIESEL
DOMESTICCOAL BURNING
BIOMASSBURNING
INCREASE IN TROPOSPHERIC OZONE BACKGROUNDINCREASE IN TROPOSPHERIC OZONE BACKGROUNDFROM INTERCONTINENTAL TRANSPORT OF POLLUTIONFROM INTERCONTINENTAL TRANSPORT OF POLLUTION
1870-1990 ozone trend at European mountain sites [Marenco et al.,1994]
Preindustrial ozone assumed in IPCC models
}
PRESENT OZONE BACKGROUND IS SIZABLE INCREMENT PRESENT OZONE BACKGROUND IS SIZABLE INCREMENT TOWARDS VIOLATION OF U.S. AIR QUALITY STANDARDSTOWARDS VIOLATION OF U.S. AIR QUALITY STANDARDS
(even more so in Europe!)(even more so in Europe!)
0 20 40 60 80 100 120 ppbv
Europe(seasonal)
U.S.(8-h avg.)
U.S.(1-h avg.)
preindustrial presentbackground
Europe (8-h avg.)
EFFECT OF NORTH AMERICAN SOURCESEFFECT OF NORTH AMERICAN SOURCESON EXCEEDANCES OF EUROPEAN AIR QUALITY ON EXCEEDANCES OF EUROPEAN AIR QUALITY
STANDARD (55 ppbv, 8-h average)STANDARD (55 ppbv, 8-h average)
GEOS-CHEM modelresults, summer 1997
Number of exceedance days(out of 92)
# of exceedance days thatwould not have happenedin absence of U.S. emissions
Li et al. [2002]
Growth of Asian emissions over next decades will Growth of Asian emissions over next decades will increase role of background for ozone air quality in U.S.increase role of background for ozone air quality in U.S.
109 atoms N cm-2 s-1
AnthropogenicNOx emissions[IPCC, 2001]
2000
2020
“Optimistic” IPCCscenario:OECD, U.S. down 20%Asia up 50%
WHAT DOES THE FUTURE HOLD?WHAT DOES THE FUTURE HOLD?Future emission scenarios from IPCC [2001] Future emission scenarios from IPCC [2001]
A1, A2, B1, B2: different socioeconomic story lines
A2: “dirty world”
B2: “clean world”
NOx
SO2
FUTURE EMISSIONS MAY BE LESS THAN PRESENT FUTURE EMISSIONS MAY BE LESS THAN PRESENT FORECASTS IF PUSH IS MADE FOR ENERGY EFFICIENCY FORECASTS IF PUSH IS MADE FOR ENERGY EFFICIENCY
AND AIR QUALITY IN DEVELOPING WORLDAND AIR QUALITY IN DEVELOPING WORLD
Streets et al. [2001]
GETTING A BIG BANG FOR THE BUCK:GETTING A BIG BANG FOR THE BUCK:controlling methane emissionscontrolling methane emissions
A 50% reduction in anthropogenic methane emissions would:• yield a fast negative global radiation forcing of 0.37 W m-2
(-0.30 W m-2 from methane, -0.07 W m-2 from ozone)• decrease the incidence of ozone > 80 ppbv in surface air over U.S. by more than 50%
[A.M. Fiore, GEOS-CHEM model results, 2002]
Historical methane trend
Recent methane trend
IPCC PROJECTION OF FUTURE METHANE EMISSIONSIPCC PROJECTION OF FUTURE METHANE EMISSIONS
Can we try to decrease methane emissions instead?
FUTURE MONITORING OF EMISSIONS FUTURE MONITORING OF EMISSIONS BY INVERSE MODELING OF ATMOSPHERIC OBSERVATIONSBY INVERSE MODELING OF ATMOSPHERIC OBSERVATIONS
3-D CHEMICAL TRANSPORT MODEL
Assimilated meteorological
data
Aerosoland chemical
processes
OPTIMIZED EMISSIONS
A PRIORI EMISSIONS
(from process model)INVERSE MODEL
OBSERVATIONS• surface• satellite• aircraft
GLOBAL MAPPING OF NOGLOBAL MAPPING OF NOx x EMISSIONS FROM SPACE:EMISSIONS FROM SPACE:
GOME observations of nitrogen dioxide (July 1996)GOME observations of nitrogen dioxide (July 1996)Martin et al. [2002]
GOME
GEOS-CHEMmodel
110 E 120 E 130 E 140 E 150 E 160 E
Longitude
0 N
10 N
20 N
30 N
40 N
50 N
Lat
itu
de
DC-8 FlightsP-3B Flights
NASA/TRACE-P AIRCRAFT MISSION TO THE PACIFIC RIMNASA/TRACE-P AIRCRAFT MISSION TO THE PACIFIC RIM(MARCH-APRIL 2001)(MARCH-APRIL 2001)
Quantifying the export of Asian pollutionQuantifying the export of Asian pollution
DC-8 and P-3 aircraft
Satellite data:MOPITT (CO)TOMS (ozone)SEAWIFS, TOMS (aerosols)
3-D chemical transportmodel forecasts
Flight tracks were designed to optimize model testing and satellite validation
DC-8flight track
INTEGRATION OF AIRCRAFT, SATELLITES, AND MODELS:INTEGRATION OF AIRCRAFT, SATELLITES, AND MODELS:quantifying the Asian dust source in TRACE-Pquantifying the Asian dust source in TRACE-P
Dust forecast for 3/21/01 (Carmichael, U. Iowa) DC8 flight track and TOMS absorbing aerosol index
SEAWIFS aerosol optical depth SEAWIFS visible image
2002 2002 2004 2004 2004 2004 2004
FUTURE SATELLITE MEASUREMENTS FUTURE SATELLITE MEASUREMENTS OF TROPOSPHERIC CHEMISTRYOF TROPOSPHERIC CHEMISTRY
MODIS/MISR
TERRA ENVISAT AURA