Satellite and Aircraft Based Constraints on NOX Emissions

Randall MartinChris Sioris Kelly Chance Tom Ryerson

Andy Neuman

Ron Cohen

UC Berkeley

Aaron Swanson Frank Flocke

NCAR

CIRES

Air Mass Factor Calculation in SCIAMACHY Retrieval Needs Air Mass Factor Calculation in SCIAMACHY Retrieval Needs External Info on Shape of Vertical ProfileExternal Info on Shape of Vertical Profile

d()

IoIB

EARTH SURFACE

RADIATIVE TRANSFER MODEL

Scattering weight

B

e

I1w

ln)(

AMF)(

G

ATMOSPHERIC CHEMISTRY MODEL

Shape factor

22

NONO )()(

airCS

1

T

dSw )()(AMFvertical

slantAMF G

Calculate w() as function of:• solar and viewing zenith angle• surface albedo, pressure• cloud pressure, frac• aerosol profile, type

IndividualSCIAMACHY Scenes

NO2 mixing ratio CNO2() norm. by column ΩNO2

() is temperature dependent cross-section

sig

ma

()

Increased NOIncreased NOxx Emissions from Midlatitude Improves GEOS-CHEM Emissions from Midlatitude Improves GEOS-CHEM

Simulation of NOSimulation of NO22 Profiles Used in Retrieval Profiles Used in Retrieval

Remaining Discrepancy In Vertical Profile of NOx Emissions Remaining Discrepancy In Vertical Profile of NOx Emissions (i.e. importance of cloud-cloud flashes)(i.e. importance of cloud-cloud flashes)

Midlatitude lightning Mean Bias in AMF:

0.4 Tg N yr-1 12% 9% 3%

1.6 Tg N yr-1 1% 5% 3%

In Situ

0.4 Tg N yr-1

1.6 Tg N yr-1

Enhanced Midlatitude Lightning Reduces Discrepancy with SCIAMACHY Enhanced Midlatitude Lightning Reduces Discrepancy with SCIAMACHY over North Atlanticover North Atlantic

Profile of NOx Emissions (lifetime) May Explain Remaining DiscrepancyProfile of NOx Emissions (lifetime) May Explain Remaining Discrepancy

May-Oct 2004

SCIAMACHY NO2 (1015 molec cm-2)

GEOS-Chem NO2 (1015 molec cm-2)

1.6 Tg N in Midlat

GEOS-Chem NO2 (1015 molec cm-2)

0.4 Tg N in Midlat

Significant Agreement Between Coincident Cloud-Filtered Significant Agreement Between Coincident Cloud-Filtered SCIAMACHY and In-Situ MeasurementsSCIAMACHY and In-Situ Measurements

r = 0.79

slope = 0.8

1:1 line

Ryerson NO2

Cohen NO2

Chris Sioris

•Coincident measurements

•Cloud-radiance fraction < 0.5

•In-situ measurements below 1 km & above 3 km

Assume constant mixing ratio below lowest measurement

Add upper tropospheric profile from mean obs

Horizontal bars show 17th & 83rd percentiles

Cloud-filtered Tropospheric NOCloud-filtered Tropospheric NO22 Columns Retrieved from Columns Retrieved from

SCIAMACHYSCIAMACHY

May-Oct 2004

detectionlimit

Errorweightin

g

Conduct a Chemical Inversion & Combine Top-Down Conduct a Chemical Inversion & Combine Top-Down and Bottom-up Inventories with Error Weightingand Bottom-up Inventories with Error Weighting

A posteriori emissionsTop-Down Emissions

1015 molec cm-2

A Priori NOx EmissionsSCIAMACHY NO2 Columns

1011 molec N cm-2 s-1

GEOS-CHEM model

May-Oct 2004

Global Optimal Emission Inventory RevealsGlobal Optimal Emission Inventory RevealsMajor Discrepancy in NOx Emissions from MegacitiesMajor Discrepancy in NOx Emissions from Megacities

r2=0.83 vs a priori

A Posteriori NOx Emissions from East Asia Exceed A Posteriori NOx Emissions from East Asia Exceed Those from Either North America or EuropeThose from Either North America or Europe

A priori (Tg N yr-1)

A posteriori (Tg N yr-1)

East Asia 6.8 9.0

North America 8.1 8.8

Europe 6.5 8.3

Africa 7.1 8.2

SE Asia & India 5.0 5.2

South America 4.4 5.1

Australia 1.1 1.8

Total 39.1 46.4

Large Change in NOx Emissions Near New York CityLarge Change in NOx Emissions Near New York City

1011 atoms N cm-2 s-1 1011 atoms N cm-2 s-1 1011 atoms N cm-2 s-1

A priori A posteriori A posteriori – A priori

7.8 Tg N 0.6 Tg N

r2 = 0.92

Evaluate Each Inventory By Conducting GEOS-CHEM Simulation & Evaluate Each Inventory By Conducting GEOS-CHEM Simulation & Sampling Model Along Aircraft Flight TracksSampling Model Along Aircraft Flight Tracks

NOx (pptv)

Simulation with A Posteriori – Simulation with A Priori

HNO3 (pptv)

7.2 Tg N

PAN (pptv)

In Situ Airborne Measurements Support In Situ Airborne Measurements Support A Posteriori InventoryA Posteriori Inventory

In Situ

GEOS-CHEM (A priori)

GEOS-CHEM (A posteriori)

New England New England New England + Gulf

P-3 Measurements from

Tom Ryerson (NOAA) Aaron Swanson Andy Neuman Frank Flocke (NCAR) (CIRES/NOAA)

Horizontal bars show 17th & 83rd percentiles

ConclusionsConclusions

Growing confidence in top-down constraint on NOx emissions

Underestimate in NOx emissions from megacities

North American lightning NOx emissions underestimated