Randall MartinAaron Van Donkelaar

Chris Sioris Kelly Chance

Lyatt Jaeglé

Space-Based Constraints on NOx Emissions Space-Based Constraints on NOx Emissions and Aerosol Single Scattering Albedoand Aerosol Single Scattering Albedo

Global Surface NOGlobal Surface NOx x Emissions Uncertain to Factor of 2Emissions Uncertain to Factor of 2Implications for Tropospheric Ozone, Aerosols, and Indirect EffectImplications for Tropospheric Ozone, Aerosols, and Indirect Effect

Relative Uncertainty

GEIA

Duncan et al.

Yienger and Levy

A priori

SCIAMACHY/GOME Spectral Measurement RegionsSCIAMACHY/GOME Spectral Measurement Regions

40 km x 320 km 30 km x 60 km

Spectral Fit of NOSpectral Fit of NO22

Scattering by Earth surface and by atmosphere

Backscatteredintensity IB

Solar Io

Distinct NO2 Spectrum

RingeIAI s

B )()()( 0

Nonlinear least-squares fitting

Ozone

NO2

O2-O2

Albedo A

Perform a Radiative Transfer Calculation to Account for Viewing Perform a Radiative Transfer Calculation to Account for Viewing Geometry and ScatteringGeometry and Scattering

Cloud Screening: Remove Scenes with ICloud Screening: Remove Scenes with IB,c B,c > 0.7*I> 0.7*IB,oB,o

RcRo

IB,o IB,c

Pc

Rs

•FRESCO Clouds Fields [Koelemeijer et al., 2002]

•Surface Reflectivity [Koelemeijer et al., 2003]

•LIDORT Radiative Transfer Model [Spurr et al., 2002]

d

Io

Cloud-filtered Tropospheric NOCloud-filtered Tropospheric NO22 Columns Observed from the Columns Observed from the

SCIAMACHY Satellite Instrument SCIAMACHY Satellite Instrument (Data (Data ICARTT) ICARTT)

May-Sept 2004

detectionlimit

NO/NO2

W ALTITUDE

Lifetime ~ hours

Major Urban Centers Are Concentrated NOx SourcesMajor Urban Centers Are Concentrated NOx Sources

May-Sept 2004

detectionlimit

1015 molecules cm-2

r = 0.75 bias=5%

JJA 1997

SPACE-BASED CONSTRAINTS ON NOSPACE-BASED CONSTRAINTS ON NOx x EMISSIONSEMISSIONS

Tropospheric NO2 ColumnsGOME GEOS-CHEM model (GEIA)

Errorweighting

A priori emissions (GEIA) A posteriori emissions Difference

Martin et al. [2003]

May-Sept 2004

43 Tg N

43 - 38 Tg N

SCIAMACHY minus a priori

Satellite Observations of Soil NOx Emissions from SahelSatellite Observations of Soil NOx Emissions from Sahel40% of African NOx Emissions from Soils40% of African NOx Emissions from Soils

Jaeglé, Martin, et al., JGR, 2004

Results for the year 2000

Aerosol Single Scattering Albedo Major Source of Aerosol Single Scattering Albedo Major Source of Uncertainty in Global Radiative Forcing EstimatesUncertainty in Global Radiative Forcing Estimates

IPCC [2001]

Maximum Sensitivity to Aerosol Optical Thickness Over Dark SurfacesMaximum Sensitivity to Aerosol Optical Thickness Over Dark SurfacesMore Sensitive to Single Scattering Albedo Over Bright SurfacesMore Sensitive to Single Scattering Albedo Over Bright Surfaces

King et al., BAMS, 1999

Saharan Dust Plume Staten Island Refinery Fire

TOMS Aerosol Index Measures Absorbing Aerosols In Ultraviolet TOMS Aerosol Index Measures Absorbing Aerosols In Ultraviolet Where Rayleigh Scattering Acts as Bright SurfaceWhere Rayleigh Scattering Acts as Bright Surface

]})/[(log])/[({log100 3603311036033110 Rayleighmeas IIIIAI

July

300 400 500 600 700 800W avelength [nm ]

0.0

0.2

0.4

0.6

Ref

lect

ivity

TOA spectral albedo measured by GOME

MODIS Optical Depth Includes Both Scattering and MODIS Optical Depth Includes Both Scattering and Absorbing AerosolsAbsorbing Aerosols

MODIS AOD at 470 nm

July 2000

July 2000

Requires • aerosol size distribution

information (AERONET and GEM-AQ)

• Aerosol relative vertical distribution (LIDAR, GEM-AQ)

Use radiative transfer model to calculate SSA that reproduces observed Aerosol Index

FundingFunding

• Canadian Foundation for Climate and Atmospheric Sciences (CFCAS)

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

• National Aeronautics and Space Administration (NASA)

• Canadian Foundation for Innovation (CFI)

• Nova Scotia Research and Innovation Trust (NSRIT)