Randall%20Martin

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Measuring Tropospheric NO2 from SCIAMACHY During
INTEX and Improving NOx Emission Inventories
Randall Martin Aaron Van Donkelaar
Yongtao Hu Armistead Russell
Chris Sioris Kelly Chance
Tom Ryerson
Jack Dibb
Bill Brune
Ron Cohen
UC Berkeley
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Spectral Fit of NO2
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
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Perform a Radiative Transfer Calculation to
Account for Viewing Geometry and Scattering
Cloud Radiance Fraction IB,c / (IB,o IB,c)
IB,c
IB,o
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
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Data Provided for all Cloud Fractions HoweverUse
of High Cloud Fraction Data Is Discouraged!Cloud
Radiance Fraction lt0.4 Recommended in Header
Reality
FRESCO Cloud Algorithm
Surface
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Sample JPGs Provided For Each Day
Missing Data Cloudy Missing Cloud
Fields Satellite Downlink Issues
Typical Individual Measurement Uncertainty (1x101
5 molec cm-2 40) Spectral Fit Stratospheric
NO2 Surface Reflectance Clouds Aerosols Assumed
NO2 Profile
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Preliminary Comparison Between Average Assumed
and Measured NO2 ProfilesNeed 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
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Reasonable Agreement Between Coincident SCIAMACHY
and In-Situ Cloud-Free MeasurementsDifficult
Comparison over Source Regions Due to Ambiguous
Column Below Aircraft and Spatial Heterogeneity
11 line
r2 0.69

• Coincident measurements
• Cloud-radiance fraction lt 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
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Cloud-filtered Tropospheric NO2 Columns Observed
from the SCIAMACHY Satellite Instrument
Jul-Aug 2004
(5x1014 molec cm-2 30)
detection limit
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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
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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
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EMIS Emissions Mapping Integration
ScienceOptimize North American NOx Emissions
SCIAMACHY NO2 Columns
NOx Emissions (SMOKE/G.Tech)
Aug 2004
May-Oct 2004
A priori emissions (SMOKE/Russell)
1011 molec N cm-2 s-1
1015 molecules cm-2
Models-3
GEOS-CHEM
Error weighting
Top-Down Emissions
A posteriori emissions
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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
0.8 Tg N yr-1
8.4 Tg N yr-1
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Evaluate Top-Down and Bottom-Up NOx
InventoriesConduct GEOS-CHEM Simulation For Each
InventorySampled GEOS-CHEM Along Flight Tracks
Simulation with SCIAMACHY Original NOx Emission
Inventory
?NOx (ppbv)
?HNO3 (ppbv)
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P3-B Measurements Support Top-Down InventoryDC-8
Measurements Inconclusive
New England
New England Gulf
Remote
In Situ
GEOS-CHEM (Top-Down)
GEOS-CHEM (Bottom-up)
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Major Discrepancy in NOx Emissions from Megacities
48 Tg N
May-Oct 2004
48 - 38 Tg N
GEIA 1998