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?

Dutch OMI U.S. OMI

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.

Molecules/cm2

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.

The OMI Swath…

AIRPACT: 9025 Points

Ghosted OMI TROP. AIRPACT OMI – TROP.

Looking at the “I-5 Corridor”

TROPOSPHERE – COLUMN NO2 – March 2007

Residuals:

OMI Pixel Density

March I-5 Area Residuals (OMI - AIRPACT)

-4.00E+15

0.00E+00

4.00E+15

2007

0302

2007

0303

2007

0304

2007

0305

2007

0306

2007

0307

2007

0308

2007

0309

2007

0310

2007

0312

2007

0313

2007

0314

2007

0315

2007

0316

Date

Avg

. Res

idu

al (m

ole

c/cm

2)

-1000

-800

-600

-400

-200

0

200

400

600

800

1000

Nu

mb

er o

f OM

I Po

ints

Avg Residual

Avg Residual w/ Ghost

# of OMI Points

OMI Pixel Density and Cloud Cover greatly influence agreement with Airpact.

Ghost Column looks promising.

Other species to look forward to…

Formaldehyde

SO2 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!

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!