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

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

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

PM2.5 and SO2 Emissions

Global Climatology (2001-2006) of PM2 Global Climatology (2001-2006) 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

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

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

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

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

Anthropogenic Emissions Differences (2006) Show Some Consistency Top-Down Minus Bottom-Up Emissions Top-down (OMI) – Bottom-up (GC) -7.6 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

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

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