1. Randall Martin Aaron Van Donkelaar Chris Sioris Kelly Chance Evaluating NOx Emission Inventories in North America and Beyond Yongtao Hu Armistead Russell Jack Dibb Tom Ryerson Ron Cohen UC Berkeley Bill Brune

2. Cloud-filtered Tropospheric NO 2 Columns Observed from the SCIAMACHY Satellite Instrument (Data  ICARTT) May-Oct 2004 detection limit

3. Error weighting EMIS: Emissions Mapping Integration Science Optimize North American NO x Emissions A priori emissions (SMOKE/Russell) A posteriori emissions Top-Down Emissions May-Oct 2004 10 15 molecules cm -2 NOx Emissions (SMOKE/G.Tech) SCIAMACHY NO 2 Columns 10 11 molec N cm -2 s -1 GEOS-CHEM Aug 2004 CMAQ

4. North American NOx Emissions (May – October) Largest Change in Northeastern US Coast 10 11 atoms N cm -2 s -1 GEOS-CHEM (NAPAP Scaled to 1998) SCIAMACHY (2004) SCIAMACHY - NAPAP 7.6 Tg N 8.4 Tg N 0.8 Tg N r 2 = 0.85

5. Evaluate Top-Down and Bottom-Up NOx Inventories Conduct GEOS-CHEM Simulation For Each Inventory Sampled GEOS-CHEM Along Flight Tracks  NO x (ppbv) Simulation with SCIAMACHY – Original NOx Emission Inventory  HNO 3 (ppbv)

6. P-3 Measurements Support Top-Down Inventory DC-8 Measurements Inconclusive In Situ GEOS-CHEM (Bottom-up) GEOS-CHEM (Top-Down) New EnglandNew England + Gulf Remote

7. May-Oct 2004 48 Tg N 48 - 38 Tg N Major Discrepancy in NOx Emissions from Megacities GEIA 1998

8. SCIAMACHY Shows Elevated NOx Export from North America May-Oct 2004 SCIAMACHY NO 2 (10 15 molec cm -2 ) GEOS-CHEM NO 2 (10 15 molec cm -2 ) May-Oct 2004

9. Explained by Model Bias in Upper Tropospheric NO x GEOS-CHEM NO 2 Cohen NO 2 Errorbars Show 17 th and 83 rd percentiles West of -60 degrees lon, “land”East of -60 degrees lon, “ocean” GEOS-CHEM NO Brune NO GEOS-CHEM low by 7.5% in column GEOS-CHEM low by factor of 2 in column

10. Thoughts on Using GEOS-CHEM Outside Harvard Support for global and nested 1 degree by 1.25 degree simulation Some way to enable more rapid release of model updates would help ensure that GEOS-CHEM remains nimble Wish List Thank you to those at Harvard (especially Bob) for being communicative! Would be impossible without this.