Simultaneous Retrievals of aerosol and surface from a combination of AERONET- MODIS-MISR-POLDER data
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Simultaneous Retrievals of aerosol and surface from a combination of AERONET- MODIS-MISR-POLDER data. Algorithm: Oleg Dubovik 1 , Alexander Sinyuk 1 , MODIS: Yoram Kaufman 1 Eric Vermote 2 Jean-Claude Roger 2

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Slide1 l.jpg

Simultaneous Retrievals of aerosol and surface from a combination of AERONET- MODIS-MISR-POLDER data

Algorithm:Oleg Dubovik1,

Alexander Sinyuk1,

MODIS: Yoram Kaufman1

Eric Vermote2

Jean-Claude Roger2

MISR: John Martonchik3,

Ralph Kahn3,

Dave Diner3,

POLDER: Francois-Marie Breon4,

AERONET: Brent Holben1,

Ilya Slutsker1

1- NASA/GSFC, Greenbelt, MD, USA

2 - UMD, Greenbelt, MD, USA

3 - NASA/JPL, CA, USA

4 - CEA/DSM/LSCE, France


Slide2 l.jpg

Retrieval of surface needs combination of AERONET- MODIS-MISR-POLDER dataatmospheric correction for aerosol effect

Retrieval of aerosol reliesonassumption of surface reflectance

Idea:Less assumptions are needed in simultaneous retrieval of aerosol and surface from combination of up- and down - looking observations


Slide3 l.jpg

Retrieval using combinations of up-looking combination of AERONET- MODIS-MISR-POLDER data

Ground-based and down-looking satellite

observations

Retrieved:

Aerosol Properties:

- size distribution

- real ref. ind.

- imag. ref. ind

(AERONET sky channels)

  • Surface Parameters:

  • BRDF (MISR, POLDER)

  • Albedo (MODIS)


Aeronet misr polder modis data l.jpg
AERONET- MISR - POLDER - MODIS data combination of AERONET- MODIS-MISR-POLDER data

  • AERONET Ground-based Sun-sky radiometer:

    - t(l) ± 0.02 at

    6 channels: 0.34, 0.38, 0.44, 0.67, 0.87, 1.02, 1.65mm

  • I(l,Q) ± 0.05% at

    4 channels: 0.38, 0.44, 0.67, 0.87, 1.02, 1.65mm

    3° ≤ scattering angles ≤ ~70°

  • P(l,Q) ± 0.02% at 0.87

  • MISR

    Reflectance at

    4 channels: 0.45, 0.55, 0.67, 0.87 mm

    9 viewing angles: ±70.5o, ± 60o,± 45.6o, ± 26.1o, 0o

  • MODIS

    Reflectance at

    7 channels: 0.47, 0.55, 0.66, 0.87,1.2, 1.6, 2.1

  • POLDER

    Reflectance at

    7 channels: 0.44, 0.49, 0.56, 0.67,0.76, 0.87, 0.91

    13 viewing angles

    Polarization at: 0.44, 0.67, 0.87


Retrieval scheme l.jpg
Retrieval scheme: combination of AERONET- MODIS-MISR-POLDER data

MISR, POLDER

MODIS

  • Forward model:

  • - Detailed aerosol (same as in AERONET)

  • Multiple scattering accounts for BRDF

  • BRDF modeled using parameterized model

  • (Rahman-Pinty-Verstraete, 1993)

Numerical inversion:

-Accounting for noise

-Solving Ill-posed problem

- Setting a priori constraints

Observations

aerosol particle sizes,

complex refractive index,

parameters of BRDF

(or Lambertian albedo)


Inversion l.jpg
Inversion combination of AERONET- MODIS-MISR-POLDER data

  • Statistically Optimized Minimization-

  • Multi-term LSM Fitting (Dubovik and King 2000; Dubovik 2004)

weighting

Lagrange parameters

  • Measurements:

  • i=1 - optical thickness

  • i=2 - AERONET radiances

  • i=3 - stellite radiances

  • their covariances

  • (should depend on l and Q)

  • -lognormal error distributions

a priori restrictions on

norms of derivatives of:

i=4 -size distr. variability;

i=5 -n spectral variability;

i=6 -k spectral variability;

i=7 - surface reflectance

spectral variability;

consistency

Indicator


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Questions & Issues: combination of AERONET- MODIS-MISR-POLDER data

  • Retrieved aerosol properties:

    • are there any improvements compare to

      conventional AERONET retrieval

  • Retrieved surface properties:

    • reliable?

    • are there any limitations?

    • what is the difference with conventional

      atmospheric correction?


Simultaneous fitting l.jpg

August 9, 2003 combination of AERONET- MODIS-MISR-POLDER data

t(0.44) ~ 0.3

Simultaneous fitting

AERONET

MODIS


Simultaneous fitting9 l.jpg

Summer, 2003 combination of AERONET- MODIS-MISR-POLDER data

MONGU

Simultaneous fitting

August 9, 2003

t(0.44) ~ 0.3

MISR-MODIS

MISR

MODIS


Comparisons of surface retrievals with improved vertical profile l.jpg
Comparisons of Surface combination of AERONET- MODIS-MISR-POLDER dataRetrievals (with improved vertical profile)

Surface Albedo:

Surface BRDF:


Effect of aerosol vertical distribution on the surface retrievals l.jpg
Effect of Aerosol combination of AERONET- MODIS-MISR-POLDER dataVertical Distribution on the Surface Retrievals

Assumed Profiles:


Surface effect on retrievals of the refractive index low aerosol loading l.jpg
Surface Effect on Retrievals of the Refractive Index combination of AERONET- MODIS-MISR-POLDER data(low aerosol loading)

POLDER: June 24, 2003

t(0.44) ~ 0.26 , SZA=470

MISR: August 9, 2003

t(0.44) ~ 0.3, SZA=400


Surface effect on the retrievals of the size distribution low aerosol loading l.jpg
Surface Effect on the Retrievals of the Size Distribution combination of AERONET- MODIS-MISR-POLDER data(low aerosol loading)

MISR: August 9, 2003

t(0.44) ~ 0.3, SZA=400

POLDER: June 24, 2003

t(0.44) ~ 0.26 , SZA=470


Surface effect on the retrievals at high aerosol loading l.jpg
Surface Effect on the Retrievals at combination of AERONET- MODIS-MISR-POLDER dataHigh Aerosol Loading

POLDER: August 18, 2003

t(0.44) ~ 0.63, SZA=350


Surface effect on the retrievals of single scattering albedo l.jpg
Surface Effect on the Retrievals of combination of AERONET- MODIS-MISR-POLDER dataSingle Scattering Albedo

MISR: August 9, 2003

t(0.44) ~ 0.3, SZA=400

POLDER: August 18, 2003

t(0.44) ~ 0.63, SZA=350


Effect of particle non sphericity on the retrievals l.jpg
Effect of combination of AERONET- MODIS-MISR-POLDER dataParticle Non-Sphericityon the Retrievals

June, 2003

Solar Village, Saudi Arabia


Surface effect on the retrievals of single scattering albedo17 l.jpg
Surface Effect on the Retrievals of combination of AERONET- MODIS-MISR-POLDER dataSingle Scattering Albedo

(Almucantar inversion with corrected surface)

POLDER: June 7, 2003

t(0.44) ~ 0.67 , SZA=700

POLDER: September 27, 2003

t(0.44) ~ 0.24 , SZA=700


Retrievals for islands or costal sites l.jpg
Retrievals combination of AERONET- MODIS-MISR-POLDER datafor Islands or Costal sites

Cape Verde (Island)


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  • Results: combination of AERONET- MODIS-MISR-POLDER data

    • Simultaneous inversion of satellite and

      AERONET data has been developed

    • Surface BRDF and Albedo can be retrieved simultaneously with aerosol (low and moderate t,)

    • Improved retrievals of aerosol:

      - refractive index and size (low tover vegetation)

      - wo(l) and size (over bright surface)

    • The approach is very useful for sites with complex surface structure (Islands, costal)

      Plans:

    • Completing analysis

    • Making operational retrievals

    • Including Lidar information


Comparisons of misr and polder geometries l.jpg
Comparisons of MISR and POLDER geometries combination of AERONET- MODIS-MISR-POLDER data

Mongu, August 7,9 ,10, 2003


Almucantar and principle plane retrievals size distribution l.jpg
Almucantar and principle plane retrievals: combination of AERONET- MODIS-MISR-POLDER data Size Distribution

POLDER: June 7, 2003

t(0.44) ~ 0.67 ,

PP: SZA=230; ALM: SZA=700

POLDER: September 27, 2003

t(0.44) ~ 0.24 ,

PP: SZA=340; ALM: SZA=700


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