1. Chris Sioris Kelly Chance
Measuring Tropospheric NO2 from SCIAMACHY During INTEX and Improving NOx Emission Inventories
Randall Martin
Aaron Van Donkelaar
Chris Sioris Kelly Chance
Yongtao Hu
Armistead Russell
Tom Ryerson
Bill Brune
Jack Dibb
Ron Cohen
UC Berkeley

2. Spectral Fit of NO2 Nonlinear least-squares fitting
Distinct NO2 Spectrum
Solar Io
Ozone
Backscattered
intensity IB
NO2
Scattering by
Earth surface
and by atmosphere
Albedo A
O2-O2
Nonlinear least-squares fitting
Also Weak H2O line
Based on Martin et al., 2002

3. Perform a Radiative Transfer Calculation to Account for Viewing Geometry and Scattering
Cloud Radiance Fraction IB,c / (IB,o + IB,c)
IB,o
IB,c Io
FRESCO Clouds Fields [Koelemeijer et al., 2002]
Surface Reflectivity [Koelemeijer et al., 2003]
LIDORT Radiative Transfer Model [Spurr et al., 2002]
GEOS-CHEM NO2 & aerosol profiles q Rc Ro Pc dt Rs
Based on Martin et al., 2002, 2003

4. Data Provided for all Cloud Fractions However Use of High Cloud Fraction Data Is Discouraged! Cloud Radiance Fraction <0.4 Recommended in Header
FRESCO Cloud Algorithm
Reality
Surface

5. Sample JPGs Provided For Each Day
Missing Data:
Cloudy
Missing Cloud Fields
Satellite Downlink Issues
Typical Individual Measurement Uncertainty
±(1x1015 molec cm %)
Spectral Fit
Stratospheric NO2
Surface Reflectance
Clouds
Aerosols
Assumed NO2 Profile

6. Preliminary Comparison Between Average Assumed and Measured NO2 Profiles Need to Continue Analysis for Individual Flights
West of -60 degrees lon, “land”
East of -60 degrees lon, “ocean”
GEOS-CHEM
Cohen NO2
Errorbars Show 17th and 83rd percentiles

7. Reasonable Agreement Between Coincident SCIAMACHY and In-Situ Cloud-Free Measurements Difficult Comparison over Source Regions Due to Ambiguous Column Below Aircraft and Spatial Heterogeneity
1:1 line
r2 = 0.69
Coincident measurements
Cloud-radiance fraction < 0.4
In-situ measurements below 1 km
Assume constant mixing ratio below lowest measurement
Cohen NO2
Ryerson NO2
Chris Sioris
In situ errorbars show 17th & 83rd percentiles – not completed for DC8

8. Cloud-filtered Tropospheric NO2 Columns Observed from the SCIAMACHY Satellite Instrument
Jul-Aug 2004
±(5x1014 molec cm %)
detection
limit

9. SCIAMACHY Shows Elevated NOx Export from North America
SCIAMACHY NO2 (1015 molec cm-2)
Jul-Aug 2004
GEOS-CHEM NO2 (1015 molec cm-2)
Jul-Aug 2004

10. SCIAMACHY Shows Elevated NOx Export from North America
SCIAMACHY NO2 (1015 molec cm-2)
May-Oct 2004
GEOS-CHEM NO2 (1015 molec cm-2)
May-Oct 2004

11. EMIS: Emissions Mapping Integration Science Optimize North American NOx Emissions
SCIAMACHY NO2 Columns
NOx Emissions (SMOKE/G.Tech)
May-Oct 2004
Aug 2004
A priori emissions (SMOKE/Russell)
1015 molecules cm-2
1011 molec N cm-2 s-1
Models-3
GEOS-CHEM
Error
weighting
Top-Down Emissions
A posteriori emissions

12. North American NOx Emissions (May – October) Largest Change in Northeastern US Coast
GEOS-CHEM
(NAPAP Scaled to 1998)
SCIAMACHY (2004)
SCIAMACHY - NAPAP
1011 atoms N cm-2 s-1
1011 atoms N cm-2 s-1
1011 atoms N cm-2 s-1
r2 = 0.85
7.6 Tg N yr-1
8.4 Tg N yr-1
0.8 Tg N yr-1

13. Evaluate Top-Down and Bottom-Up NOx Inventories Conduct GEOS-CHEM Simulation For Each Inventory Sampled GEOS-CHEM Along Flight Tracks
Simulation with SCIAMACHY – Original NOx Emission Inventory
NOx (ppbv)
HNO3 (ppbv)

14. P3-B Measurements Support Top-Down Inventory DC-8 Measurements Inconclusive
New England
New England + Gulf
Remote
In Situ
GEOS-CHEM (Top-Down)
GEOS-CHEM (Bottom-up)

15. Major Discrepancy in NOx Emissions from Megacities
48 Tg N
May-Oct 2004
Most Recent Edgar Emissions for 1995
Tg N
GEIA 1998