1. USING SATELLITES TO BETTER UNDERSTAND THE POLICY-RELEVANT BACKGROUND OF SURFACE OZONE
Daniel J. Jacob, Lin Zhang, Dylan B. Millet, Paul I. Palmer (now at Leeds),
Tzung-May Fu, Solene Turquety (now at CNES), Monika Kopacz
Supported by NASA
with Kelly V. Chance and Thomas Kurosu (Harvard/SAO)
and the TES, OMI, MOPITT Science Teams
EPA POLICY-RELEVANT BACKGROUND (PRB): ozone that would be present in surface air in absence of North American anthropogenic emissions.
Important for:
setting the NAAQS - incremental risk from ozone above background;
assessing intercontinental pollution influence

2. PROCESSES DETERMINING PRB OZONE AND RELEVANT SATELLITE OBSERVATIONS
Ozone profiles (HRDLS)
tropopause
Strat-trop exchange
Nitric acid (TES),
NO2 (GOME, SCIA, OMI)
Lightning
Free tropospheric ozone
(GOME)
Ozone-CO correlations (TES)
Intercontinental
ozone pollution
Continental boundary layer
Hotspots, scars (MODIS, MISR)
CO (MOPITT, AIRS, TES)
Formaldehyde and NO2 columns
(GOME, SCIA, OMI)
Fires
Biogenic VOCs and NOx

3. USING TES OZONE-CO DATA TO OBSERVE INTERCONTINENTAL OZONE POLLUTION
602 hPa TES observations, July 2005
Ozone-CO relationship
downwind of Asia
TES
R=0.64
Slope=0.62
Ozone
Ozone (ppbv)
ppbv
GEOS-Chem
with AK
R=0.84
Slope=0.50
Carbon monoxide (pppbv) CO
ppbv
Lin Zhang, Harvard

4. USING TES OZONE-CO DATA TO OBSERVE INTERCONTINENTAL OZONE POLLUTION
618 hPa TES observations, July 2005
Ozone-CO relationship
downwind of eastern N. America
TES
R=0.38
Slope=0.75
Ozone
Ozone (ppbv)
ppbv
GEOS-Chem
with AK
R=0.79
Slope=0.67
Carbon monoxide (pppbv) CO
TES rertrieval noise
weakens the correlation
ppbv
Lin Zhang, Harvard

5. TES OBSERVATION OF UPPER TROPOSPHERIC HNO3
tests lightning and other high-altitude sources of NOx
Sept TES data:
hot spots over N. America, Europe, and Africa
(lightning, fuel combustion,
biomass burning)
GEOS-Chem model
Susan S. Kulawik, JPL

6. INVERTING HCHO COLUMN DATA FOR ISOPRENE EMISSION
Palmer et al. [2001, 2003]
GOME slant columns (July 96)
instrument
sensitivity
HCHO vmr
Sigma coordinate
Air Mass Factor
with GEIA
isoprene
emission
inventory
GOME vertical columns (July 96)
Southeast U.S.
slope S
HCHO column
GEOS-Chem
CTM
non- isoprene contribution
EISOPRENE
EISOPRENE =(1/S)D WHCHO
Observed HCHO, ppb
Model HCHO, ppb
with GOME
isoprene
emission
inventory
GOME
isoprene
emission
inventory
validation
With HCHO
surface air
observations

7. TEST AMF CALCULATION AND HCHO SOURCE ATTRIBUTION
Aircraft 0-10 km HCHO profiles over N. America in INTEX-A (summer 2004)
Observed HCHO columns (A. Fried)
A. Fried (NCAR)
B.G. Heikes (URI)
GEOS-Chem model
Mean HCHO profiles
Observed AMF
Isoprene drives HCHO column variability; molar yield of 1.6 ± 0.5
Clouds are the principal source of AMF error (30% for cloud cover of 40%)
Overall 40% error on inferred isoprene emission
Millet et al. [2006]

8. GOME vs. MEGAN ISOPRENE EMISSION INVENTORIES (2001)
MEGAN: new emission inventory for biogenic VOCs [Guenther et al., 2006]
MEGAN GOME MEGAN GOME
May
Jun
Jul
Aug
Sep
Good accord for seasonal variation, regional distribution of emissions;
GOME 10-30% higher than MEGAN depending on month, differences in hot spot locations
Palmer et al. [2006]

9. PRELIMINARY HCHO COLUMN DATA FROM OMI (Jul. 2005)
consistent with GOME maximum over southeast Atlantic states
Thomas Kurosu and Kelly V. Chance (Harvard/SAO)

10. GOME HCHO COLUMNS OVER EAST ASIA (1996-2001)
Monthly mean GOME HCHO vertical columns (VC) [10e16 molec cm-2] over East Asia averaged between 1996 and 2001 (left panel), compared with HCHO VC from the GEOS-Chem model using a priori emissions for 2001 (right panel). Both GOME and model show a distinctive seasonal progression reflecting the seasonality of photochemistry. Several discrepancy between GOME and model stands out: during winter months (DJF), GOME HCHO VC are consistently higher than those of the model, especially over China. The locations of the excess GOME HCHO match the locations of major Chinese cities and correspond well with the a priori anthropogenic emissions. During summer months (MJJA), GOME shows very high HCHO VC in central and northern China that are absent in the model. In particular, the GOME HCHO hot spot over North China Plain in June and July is a recurring feature seen consistently through the 6 years of observation.
GOME is a UV solar backscatter instrument aboard the ERS-2 satellite launched in April HCHO slant columns are retrieved to < 4e16 molecules/cm2 sensitivity by directly fitting GOME radiance measurements at nm [Chance et al., 2000]. In order to convert the slant columns to tropospheric vertical columns, the GEOS-Chem model is used to calculate the air mass factor (AMF). The raw slant columns contain biases associated with diffuser plate and non-tropospheric contamination; these biases are removed by forcing the GOME vertical columns to match those from the GEOS-Chem model over the remote Pacific.
The a priori anthropogenic (FF+BF) emissions for Asia is from Streets et al. [2003] including ethene and xylene. Biomass burning emissions incorporate annual emission map for Asia from Streets et al. [2003], allocated seasonally according to Duncan et al. [2003]. For both anthropogenic and biomass burning emissions, CO and NOx have been adjusted based on inverse study results by Heald et al. [2004] and Wang et al. [2004]. Biogenic emissions are from MEGAN (Guenther et al. [2005]) except for acetone, which is from Jacob et al. [2002].
1016 molecules cm-2
Winter data imply vehicular VOC emissions 3x Streets et al. [2003] inventory
Large, previously recognized agricultural burning source in E. China in Jun-Jul
Biogenic emissions 3x higher than MEGAN
Tzung-May Fu , Harvard

11. USING MODIS TO MAP FIRES AND MOPITT CO TO OBSERVE EMISSIONS
Bottom-up emission inventory (Tg CO) for North American fires in Jul-Aug 2004
From above-ground vegetation From peat
18 Tg CO
9 Tg CO
MOPITT CO Summer 2004
GEOS-Chem CO x MOPITT AK
without
peat
burning
with
peat
burning
MOPITT data support large peat burning source,
pyro-convective injection to upper troposphere
Solene Turquety, Harvard/CNES

12. USING ADJOINTS OF GLOBAL MODELS TO INVERT FOR EMISSIONS WITH HIGH RESOLUTION
MOPITT daily CO columns
(TRACE-P, Mar-Apr 2001)
Scaling factors for a priori CO sources obtained with
4D-var using the GEOS-Chem model adjoint
A priori emissions from
Streets et al. [2003] and
Heald et al. [2003]
Monika Kopacz, Harvard

13. LOOKING TO THE FUTURE: L-1 AIR QUALITY MISSION
Daedalus and Janus RFI concepts
Continuous global observation of Earth sunlit disk with 5 km nadir resolution
UV-IR spectrometers for observation of ozone, NO2, HCHO, CO, aerosols
Global continuous view from L-1 critical for observation of hemispheric pollution, tropospheric background, greenhouse gases
Bridge with interests of climate, upper atmosphere, space weather, solar physics communities
L-1 point : 1.5 million km from Earth
along Earth- Sun line
NH and SH summer views from L-1:
global continuous daytime coverage