Randall Martin

Space-based Constraints on Emission Inventories of Nitrogen Oxides

Chris Sioris, Kelly Chance (Smithsonian Astrophysical Observatory)Chris Sioris, Kelly Chance (Smithsonian Astrophysical Observatory)Lyatt Jaeglé (Univerisity of Washington) Lyatt Jaeglé (Univerisity of Washington)

Tom Ryerson (NOAA)Tom Ryerson (NOAA)

Relative Uncertainty

Global Surface NOGlobal Surface NOx x Emissions Uncertain to Factor of 2Emissions Uncertain to Factor of 2Implications for Tropospheric Ozone, Aerosols, Indirect Effect, Nutrient DeliveryImplications for Tropospheric Ozone, Aerosols, Indirect Effect, Nutrient Delivery

Here in Tg N yr-1 (based on)Fossil Fuel 24 (GEIA)

Biomass Burning 6 (Duncan et al., 2003)

Soils 5 (Yienger and Levy, 1995)

NOx Emissions (Tg N yr-1)Fossil Fuel (20-33) Biomass Burning (3-13) Soils (4-21)

Top-Down Information from the GOME and Top-Down Information from the GOME and SCIAMACHY Satellite InstrumentsSCIAMACHY Satellite Instruments

•Nadir-viewing solar backscatter instruments including ultraviolet and visible wavelengths

• Low-elevation polar sun-synchronous orbit, late morning observation time

•GOME 1995-2002•Spatial resolution 320x40 km2

•Global coverage in 3 days

•SCIAMACHY 2002-presentSpatial resolution 60x30 km2

Global coverage in 6 days

Cloud-filtered Tropospheric NOCloud-filtered Tropospheric NO22 Columns Determined from SCIAMACHY Columns Determined from SCIAMACHY

May-Oct 2004

detectionlimit

Retrieval based on Martin et al., 2002, 2003

Retrieval:

Spectral fit

Remove stratosphere

Account for scattering

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

NO/NO2

W ALTITUDE

May-Oct 2004

48 Tg N yr-1

48 – 39 Tg N yr-1

A Posteriori Emission Inventory RevealsA Posteriori Emission Inventory RevealsMajor Discrepancy in NOx Emissions from MegacitiesMajor Discrepancy in NOx Emissions from Megacities

GEIA

r2=0.82 vs a priori

ICARTT: COORDINATED ATMOSPHERIC CHEMISTRY CAMPAIGN OVER ICARTT: COORDINATED ATMOSPHERIC CHEMISTRY CAMPAIGN OVER EASTERN NORTH AMERICA AND NORTH ATLANTIC IN SUMMER 2004EASTERN NORTH AMERICA AND NORTH ATLANTIC IN SUMMER 2004

International, multi-agency collaboration targeted at regional air quality, pollution outflow, transatlantic transport, aerosol radiative forcing

Terra

ERS

MISR, MODIS, MOPITT

ERS-2

GOME

Envisat

SCIAMACHY

Aqua

AIRS, MODIS

NASA DC-8

UK BAE-143

DLR Falcon

NOAA-P3

Canada Convair

NASAProteus

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

8.3 Tg N 1.1 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 (ppbv)

Simulation with A Posteriori – Simulation with A Priori

HNO3 (ppbv)

7.2 Tg N

In Situ Airborne Measurements Support Top-Down In Situ Airborne Measurements Support Top-Down InventoryInventory

In Situ

GEOS-CHEM (A priori)

GEOS-CHEM (A posteriori)

New England New England + Gulf Remote

P-3 Measurements from Tom Ryerson (NOAA)

Speciated Inventory for Soil emissionsSpeciated Inventory for Soil emissionsA posteriori 70% larger than a priori!

A prioriA priori A posterioriA posteriori

Largest soil emissions: seasonally dry tropical + fertilized cropland ecosystems

(±200%) (±90%)

r2 = 0.62

Soils

Onset of rainy season: Pulsing of soil NOx!

North Eq. Africa

Jaeglé et al., 2005

ConclusionsConclusions

• Growing confidence in top-down constraint on NOx emissions

• Gross-underestimate in NOx emissions from megacities

• Soil NOx emissions underestimated, especially from Northern Equatorial Africa

Funding:

• National Aeronautics and Space Administration (NASA)

• Canadian Foundation for Innovation (CFI)

• Nova Scotia Research and Innovation Trust (NSRIT)

• Natural Sciences and Engineering Research Council of Canada (NSERC)