CONSTRAINING EMISSION INVENTORIES USING SPACE-BASED OBSERVATIONS OF ATMOSPHERIC COMPOSITION

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CONSTRAINING EMISSION INVENTORIES USING
SPACE-BASED OBSERVATIONS OF ATMOSPHERIC
COMPOSITION

Daniel Jacob Paul Palmer Dorian Abbot
Randall Martin Kelly Chance Thomas Kurosu
Mian Chin Sushil Chandra Jerry Ziemke
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PRESENT AND FUTURE SATELLITE OBSERVATIONS OF
TROPOSPHERIC CHEMISTRY
Increasing spatial resolution
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CHALLENGE FOR THE NEXT DECADE IMPROVE EMISSION
INVENTORIES
Over 100 million Americans live in regions
failing to achieve compliance with the ozone
standard EPA
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Historical records imply a large anthropogenic
contribution to the present-day ozone
backgroundat northern midlatitudes
Ozone trend from European mountain observations,
1870-1990
Marenco et al.,1994
Major greenhouse gas
Largely controls atmospheric oxidation
Primary constituent of smog
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GLOBAL BUDGET OF TROPOSPHERIC OZONE
Global sources and sinks, Tg O3 yr-1 (GEOS-CHEM
model)
?
Formaldehyde (HCHO)
?
?
hv
hv,H2O
Nitrogen oxides (NOx) CO, VOCs
Ozone (O3)
Hydroxyl (OH)
Fires
Biosphere
Human activity
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BOTTOM-UP EMISSION INVENTORIES ARE NOTORIOUSLY
DIFFICULT TO DETERMINE!

• Fuel use estimates
• Measurements of emission ratios
• Process studies
• Estimate biological density
• Temperature, water, dependence of biological
  activity
• Extreme events

"Trees cause more pollution than automobiles do."
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HOW DO WE EVALUATE AND IMPROVE A PRIORI BOTTOM-UP
INVENTORIES?
Surface NOX
Isoprene during July
North American Isoprene Emissions (3-15 Tg
C yr-1)
Global NOx Emissions (Tg N yr-1) Fossil Fuel
(20-33) Biomass Burning (3-13) Soils
(4-21)
GEIA
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TOP-DOWN INFORMATION FROM THE GOME SATELLITE
INSTRUMENT

• Operational since 1995
• Nadir-viewing solar backscatter instrument
  (237-794 nm)
• Low-elevation polar sun-synchronous orbit, 1030
  a.m. observation time
• Spatial resolution 320x40 km2, three cross-track
  scenes
• Complete global coverage in 3 days

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USE GOME MEASUREMENTS TO RETRIEVE NO2 AND HCHO
COLUMNS TO MAP NOx AND VOC EMISSIONS
GOME
Tropospheric NO2 column ENOx Tropospheric HCHO
column EVOC
BOUNDARY LAYER
NO2
NO
HCHO
NO/NO2 ? ? W ALTITUDE
OH
CO
hours
hours
VOC
lifetime lt1 day
HNO3
Emission
Emission
NITROGEN OXIDES (NOx)
VOLATILE ORGANIC COMPOUND (VOC)
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PERFORM A SPECTRAL FIT OF SOLAR BACKSCATTER
OBSERVATIONS
absorption
Solar Io
l1
l2
Backscattered intensity IB
wavelength
Slant optical depth
Slant column
Scattering by Earth surface and by atmosphere
EARTH SURFACE
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GOME HCHO SLANT COLUMNS (JULY 1996)
Hot spots reflect high VOC emissions from fires
and biosphere
BIOGENIC ISOPRENE IS THE MAIN SOURCE OF HCHO IN
U.S. IN SUMMER
K. Chance
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SLANT COLUMNS OF NO2 FROM GOMEDominant
stratospheric structure (where NO2 is produced
from N2O oxidation)Also see tropospheric hot
spots (fossil fuel and biomass burning)
Remove strat instrument artifacts using obs
over Pacific
Martin et al., 2002b
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SLANT COLUMNS OF TROPOSPHERIC NO2 FROM GOME
1996
Martin et al., 2002b
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GEOS-CHEM MODEL

• Assimilated Meteorology (GEOS)
• 2ox2.5o horizontal resolution, 26 layers in
  vertical
• O3-NOx-hydrocarbon chemistry
• Radiative and chemical effects of aerosols
• Emissions
• Fossil fuel GEIA (NOx), Logan (CO), Piccot
  (NMHCs)
• Biosphere modified GEIA (hydrocarbons)
  Yienger/Levy (soil NOx)
• Lightning Price/Rind/Pickering, GEOS convective
  cloud tops
• Interannually varying biomass burning
• Cross-tropopause transport
• Deposition

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Radiative and chemical (uptake HO2, NO2, NO3)
effects of aerosols (sulfate, EC, OC, Dust,
Sea-Salt)
AEROSOLS REDUCE ATMOSPHERIC OXIDATION AND SURFACE
OZONE
GEOS-CHEM August 600 m
? OH ()
? O3 (ppbv)
Martin et al., 2003
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IN SCATTERING ATMOSPHERE, AMF CALCULATIONNEEDS
EXTERNAL INFO ON SHAPE OF VERTICAL PROFILE
RADIATIVE TRANSFER MODEL
ATMOSPHERIC CHEMISTRY MODEL
a priori Shape factor
sigma (?)
NO2 mixing ratio CNO2(?) norm. by column ONO2
Scattering weight
?(?) is temperature dependent cross-section
INDIVIDUAL GOME SCENES

• Calculate w(?) as function of
• solar and viewing zenith angle
• surface albedo, pressure
• cloud optical depth, pressure, frac
• aerosol profile, type

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JULY 1996
Clear-sky NO2 AMF
Fraction of IB From Clouds
Actual NO2 AMF accounting for clouds
Martin et al., 2002b
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VERTICAL COLUMNS CONFINED TO REGIONS OF SURFACE
EMISSIONSCloud/albedo artifacts removed by AMF
calculation
NO/NO2 ? ? WITH ALTITUDE NOx lifetime
lt1day No clear lightning signal
Martin et al., 2002b
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GOME Tropospheric NO2
GEOS-CHEM Tropospheric NO2
r0.75 bias 5
1015 molecules cm-2
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STRATEGY OPTIMIZE INVENTORIES USING A
PRIORI BOTTOM-UP AND GOME TOP-DOWN INFORMATION
Top-down emissions
A priori emissions
A posteriori emissions
Top-down errors
A priori errors
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TOP-DOWN ERROR IN NOX EMISSIONS
GOME Spectrum (423-451 nm)
Spectral fit and removal of stratospheric column
1x1015 molecules cm-2
Tropospheric NO2 Slant Column
AMF (surface reflectivity, clouds,
aerosols, NO2 profile)
40 of tropospheric column
Tropospheric NO2 Column
30 of tropospheric column
NOx Lifetime (GEOS-CHEM)
NOx Emissions
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TOP-DOWN INFORMATION FROM GOME REDUCES ERROR IN
NOX EMISSION INVENTORY
Bottom-up error ?a
Top-down error ?t
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OPTIMIZED NOX EMISSIONS
37.7 Tg N yr-1
36.4 Tg N yr-1
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DIFFERENCE BETWEEN A POSTERIORI AND A PRIORI
Annual mean ratio (A posteriori / A priori)
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TOMS/MLS TROPOSPHERIC OZONE CONFIRMS A PRIORI
BIOMASS BURNING NOX EMISSIONS HIGH OVER INDIA
30 N
Dobson Units for March, April, May
TOMS/MLS Chandra et al. 2003
30 S
30 N
GEOS-CHEM
30 S
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Ozone enhancement from lightning (GEOS-CHEM)
largely explains observed wave-1 pattern in TOMS
ozone
INTERPRET OBSERVATIONS OF TROPOSPHERIC OZONE
Martin et al., 2002a
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ISOPRENE EMISSIONS FOR JULY 1996 DETERMINED FROM
GOME FORMALDEHYDE COLUMNS
GOME
COMPARE TO
GEIA (IGAC inventory)
Palmer et al., 2003
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Palmer et al., 2003
EVALUATE GOME ISOPRENE INVENTORY BY COMPARISON
WITH IN SITU OBSERVATIONS USING GEOS-CHEM MODEL
AS INTERMEDIARY
CONSISTENT WITH IN-SITU HCHO OBSERVATIONS
GOME (A posteriori)
GEIA (A priori)
r2 0.53
r2 0.77
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GOME HCHO COLUMNS SHOW SEASONAL VOC EMISSIONS
JUL
MAR
AUG
APR
MAY
SEP
OCT
JUN
D. Abbot
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QUANTIFY INTERANNUAL VARIATION IN NOx AND VOC
EMISSIONS
1996
1995
GOME HCHO Columns in August
1997
1998
1999
2000
D. Abbot
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DETERMINE NOX AND VOC EMISSIONS AT HIGHER
RESOLUTION Higher resolution enables more
accurate AMF calculation
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IMPROVE EMISSION INVENTORIES OF SOIL NOX EMISSIONS
GOME Tropospheric NO2 Columns
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INTEGRATED ANALYSIS OF BIOMASS BURNING EMISSIONS
GOME HCHO
GOME NO2
MODIS AEROSOL OPTICAL DEPTH and SIZE
ATSR FIRECOUNTS
MOPITT CO
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CONSTRAIN AEROSOL EMISSION INVENTORIES
MODIS TEAM
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GEOS-CHEM model calculation of surface ozone
enhancements caused by anthropogenic emissions
from North America during July
QUANTIFY INTERCONTINENTAL TRANSPORT OF POLLUTION
Li et al. 2002
MOPITT CO Column during Mar-Apr 2001
GEOS-CHEM CO Column
Heald et al. 2003
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PRESENT AND FUTURE SATELLITE OBSERVATIONS OF
TROPOSPHERIC CHEMISTRY
Increasing spatial resolution