1. Recent Developments in Satellite Remote Sensing of Air Quality Parameters
Randall Martin, Dalhousie and Harvard-Smithsonian
Chulkyu Lee, Aaron van Donkelaar, Lok Lamsal, Dalhousie University
Nick Krotkov, Ralph Kahn, Rob Levy, Ed Celarier, Eric Bucsela, NASA
Folkert Boersma, Ruud Dirksen, KNMI
Andreas Richter, University of Bremen

2. Air Quality Parameters
Emissions, Trends, Long-range transport, Surface concentrations, O3-NOx-VOC sensitivity, Lifetime
Synergy from multiple species
Outline
NO2 (NOx lifetime): Lok Lamsal
AOD  PM2.5: Aaron van Donkelaar
SO2 (evaluation and emissions): Chulkyu Lee

3. Tropospheric NO2 (1015 molecules cm-2)
NOx Lifetime Drives the Seasonal Variation in Tropospheric NO2 Over Eastern US
Weak (<10%) Seasonal Variation in NOx Emissions or NO2/NOx
NOx Lifetime (τ)
OMI NO2 (DP_GC)
Tropospheric NO2 (1015 molecules cm-2)
Bottom-up
OMI
GEOS-Chem
GEOS-Chem Simulation
τOMI
τGC
τGC
Gas phase (NO2+OH)
OMI time
Daily Average
Heterogeneous (N2O5 Hydrolysis)
OMI time
Lamsal et al., JGR, submitted 3

4. PM2.5 and SO2 Emissions

5. Global Climatology (2001-2006) of PM2
Global Climatology ( ) of PM2.5 from MODIS & MISR AOD and GEOS-Chem AOD/PM2.5 Relationship
Evaluation for US/Canada
r=0.78 slope=1.02 n=1073
Evaluation with measurements outside Canada/US
Number sites
Correlation
Slope
Bias (ug/m3)
Including Europe
297
0.75
0.89
0.52
Excluding Europe
107
0.76
0.96
-2.8
van Donkelaar et al., EHP, in prep

6. Insight into Aerosol Source/Type with Precursor Observations
Operational OMI PBL SO2 data corrected with local air mass factor improves agreement of OMI SO2 versus aircraft observations (INTEX-B)
Orig: slope = 1.6, r=0.71 New: slope = 0.95, r=0.92
OMI Improved SO2 Vertical Columns for 2006
Lee et al., JGR, in press

7. Anthropogenic Sources Dominate Annual Mean SO2 Column
Volcanic SO2 Emissions 10% of Anthropogenic Source
GEOS-Chem Simulations for 2006
Total SO2 Column
Anthropogenic SO2 Column
Fraction from Anthropogenic
Chulkyu Lee

8. Use OMI and SCIAMACHY SO2 Columns to Map SO2 Emissions
Tropospheric SO2 column ~ ESO2 Over Land
day
OH, cloud
SO42-
DMS
SO2
~day
Deposition
Emission
Phytoplankton
Combustion, Smelters, Volcanoes
Top-Down Emissions

9. Bottom-Up in GEOS-Chem
Global Anthropogenic Sulfur Emissions Over Land for 2006 Volcanic SO2 Columns (>10 DU) Excluded From Inversion
Top-Down (OMI)
47.0 Tg S/yr
Bottom-Up in GEOS-Chem
(EDGAR2000, NEI99, EMEP2005, Streets2006) Scaled to 2006
r = 0.77
54.6 Tg S/yr
SO2 Emissions (1011 molecules cm-2 s-1)
Cloud Radiance Fraction < 0.2
Chulkyu Lee

10. Anthropogenic Emissions Differences (2006) Show Some Consistency
Top-Down Minus Bottom-Up Emissions
Top-down (OMI) – Bottom-up (GC) Tg S/yr
Top-down (SCIAMACHY)– Bottom-up (GC) -2.6 Tg S/yr
ΔSO2 Emissions (1011 molecules cm-2 s-1)
Cloud Radiance Fraction < 0.2
Chulkyu Lee

11. Indirect Validation of OMI and SCIAMACHY SO2 with Surface Measurements Infer Surface SO2 from OMI and SCIAMACHY Using GEOS-Chem SO2 Profiles
Year 2006
Cloud
Radiance
Fraction
< 0.2
slope=0.79 r=0.81
slope=0.91 r=0.86
In Situ (at OMI)
In Situ (at SCIA)
GEOS-Chem: r=0.83, slope=0.81(at OMI) and 0.84(at SCIA)
Chulkyu Lee

12. Encouraging Prospects for Applying SO2 Observations to Constrain Anthropogenic Emissions
Challenges
Better understanding of differences between OMI and SCIAMACHY
Reduce uncertainty in simulated SO2 lifetime
Develop adjoint-based inversion
OMI NO2 Columns Provide Information into NOx Loss Processes
Wintertime Observations Reflect Heterogeneous Processes