1. My first look at Tropospheric NO 2 data for the Pacific NW. Whats that in Nevada? Why are the Dutch and US. data sets so different? Dutch OMIU.S. OMI

2. So, what has Farren been doing since? Converted OMI VCD (molec/cm 2 ) into a mixing ratio for comparison to AIRPACT. Tried uniform PBL, then MM5 PBL. This produced good results but caused problems over water (and “assumes” all Tropospheric NO 2 is within the PBL) Looked at fires (large discrepancy). Now: AIRPACT is converted into a VCD value using Press. & Temp. of each Layer and then compared to OMI. “Below Cloud” ghost column being considered and we NEED to implement averaging kernels. Almost completely automated for monthly comparisons.

3. Molecules/cm 2 February 1, 2007 near 21:00 UTC AIRPACT – Vertical Column Density – NO2 US OMI – Vertical Column Density – Tropo. NO2 Cloud Fraction over 50% shown as black contour. After looking at many days, emissions for AIRPACT look low (on average) for non-Seattle urban areas.

4. The OMI Swath… AIRPACT: 9025 Points

5. Ghosted OMI TROP.AIRPACTOMI – TROP. Looking at the “I-5 Corridor” TROPOSPHERE – COLUMN NO 2 – March 2007 Residuals: OMI Pixel Density

6. OMI Pixel Density and Cloud Cover greatly influence agreement with Airpact. Ghost Column looks promising.

7. Other species to look forward to… Formaldehyde

8. SO 2 from Mountains? A high SO2 emission event… can we see it? Mt. St. Helens – Oct. 7, 2004 Effects of Striping is evident… but the OMI folks are working hard!

9. What does the Future Hold? Implement automated comparison of AIRPACT with OMI (Multiple Species? Make it available on the web?) Implement Quality Flags and Averaging Kernels for comparisons (eliminate low pixel density, and high CFRAC) Evaluate emissions inventory used in AIRPACT for urban areas. Grrrrrrrr…. Bad CLOUDS!