Refining AIRPACT vs OMI NO2 Comparison

1
Dutch OMI
U.S. OMI
My first look at Tropospheric NO2 data for the
Pacific NW. Whats that in Nevada? Why are the
Dutch and US. data sets so different?
2
So, what has Farren been doing since?

• Converted OMI VCD (molec/cm2) 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 NO2 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
February 1, 2007 near 2100 UTC AIRPACT
Vertical Column Density NO2 US OMI
Vertical Column Density Tropo. NO2
Molecules/cm2
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
Looking at the I-5 Corridor TROPOSPHERE
COLUMN NO2 March 2007
Ghosted OMI TROP.
AIRPACT
OMI TROP.
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
SO2 from Mountains?
Mt. St. Helens Oct. 7, 2004
A high SO2 emission event can we see it?
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!