Abstract

The calibration of an ocean-color sensor or validation of water products is generally based on ground-based extinction measurements from which the aerosol products (optical thickness τa and aerosol type) are deduced. Sky-radiance measurements complement the extinction measurements mainly in the aerosol-model characterization. Our basic goal is to promote calibration-validation activities based on the radiative properties of the aerosols rather than their chemical or physical properties. A simple method is proposed (and evaluated) to convert sky radiances measured in the principal plane into atmospheric phase functions P. Indeed τa and P are the required inputs to a radiative-transfer code for predicting the top-of-the-atmosphere radiances. The overall error in this prediction is a few percent. This method can operate on a worldwide network on ground-based sun radiometers and then be used to achieve a statistical analysis for validating satellite products.

© 2003 Optical Society of America

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References

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  1. H. R. Gordon, “Calibration requirements and methodology for remote sensors viewing the ocean in the visible,” Remote Sens. Environ. 22, 103–126 (1987).
    [CrossRef]
  2. R. A. Barnes, R. E. Eplee, “The SeaWiFS solar diffuser,” in SeaWiFS Calibration Topics, Part 1, NASA Tech. Memo 104566, 39, R. A. Barnes, E-N. Yeh, R. E. Eplee, eds. (NASA Goddard Space Flight Center, Greenbelt, Md., 1996).
  3. H. H. Kieffer, R. L. Widley, “Establishing the moon as a spectral radiance standard,” J. Atmos. Ocean. Technol. 13, 360–375 (1996).
    [CrossRef]
  4. R. A. Barnes, R. E. Eplee, F. S. Patt, C. R. McClain, “Changes in the radiometric sensitivity of SeaWiFS determined from lunar and solar-based measurements,” Appl. Opt. 38, 4649–4664 (1999).
    [CrossRef]
  5. M. Wang, B. Franz, “Comparing the ocean color measurements between MOS and SeaWiFS: a vicarious intercalibration approach for MOS,” IEEE Trans. Geosci. Remote Sens. 38, 184–197 (2000).
    [CrossRef]
  6. H. R. Gordon, T. Zhang, “How well can radiance reflected from the ocean-atmosphere system be predicted from measurements at the sea surface?” Appl. Opt. 35, 6527–6543 (1996).
    [CrossRef] [PubMed]
  7. B. Holben, T. Eck, I. Slutsker, D. Tanré, J. P. Buis, A. Setzer, E. Vermote, J. Reagan, Y. Kaufman, T. Nakajima, F. Lavenu, I. Jankowiak, A. Smirnov, “AERONET—a federated instrument network and data archive for aerosol characterization,” Remote Sens. Environ. 66, 1–16 (1998).
    [CrossRef]
  8. H. R. Gordon, M. Wang, “Retrieval of water-leaving radiances and aerosol optical thickness over the oceans with SeaWiFS: a preliminary algorithm,” Appl. Opt. 33, 443–452 (1994).
    [CrossRef] [PubMed]
  9. J. L. Deuzé, M. Herman, R. Santer, “Fourier series expansion of the transfer equation in the atmosphere-ocean system,” J. Quant. Spectrosc. Radiat. Transfer 41, 483–494 (1989).
    [CrossRef]
  10. R. Santer, M. Herman, “Particle size distributions from forward scattered light using the Chahine inversion scheme,” Appl. Opt. 22, 2294–2301 (1983).
    [CrossRef] [PubMed]
  11. T. Nakajima, M. Tanaka, T. Yamauchi, “Retrieval of the optical properties of aerosols from aureole and extinction data,” Appl. Opt. 22, 2951–2959 (1983).
    [CrossRef] [PubMed]
  12. M. Wang, H. R. Gordon, “Retrieval of the columnar aerosol phase function and single scattering albedo from sky radiance over the ocean: simulations,” Appl. Opt. 32, 4598–4609 (1993).
    [CrossRef] [PubMed]
  13. O. Dubovik, M. King, “A flexible inversion algorithm for retrieval of aerosol optical properties from Sun and sky radiance measurements,” J. Geophys. Res. 105, (ND16), 20,673–20,6962000.
  14. C. Devaux, A. Vermeulen, J. L. Deuzé, P. Dubuisson, M. Herman, R. Santer, “Retrieval of aerosol single scattering albedo from ground-based measurements: application to observational data,” J. Geophys. Res. 103, 8753–8761 (1998).
    [CrossRef]
  15. E. P. Shettle, R. W. Fenn, “Models of the aerosols of the lower atmosphere and the effects of humidity variations on their optical properties,” Technical Report 0214 (Air Force Geophysical Laboratory, Hanscom Air Force Base, Mass., 1979).
  16. D. Tanré, C. Deroo, P. Duhaut, M. Herman, J. Morcrette, J. Perbos, P. Y. Deschamps, “Description of a computer code to simulate the satellite signal in the solar spectrum: 5S code,” Int. J. Remote Sens. 11, 659–668 (1990).
    [CrossRef]
  17. N. Martiny, R. Santer, “Atmospheric corrections over coastal waters for SeaWiFS: validation using ground-based measurements,” in Ocean Optics: Remote Sensing and Underwater Imaging, G. D. Gilbert, R. J. Frouin, eds., Proc. SPIE4488, 184–194 (2002).
    [CrossRef]

2000 (2)

M. Wang, B. Franz, “Comparing the ocean color measurements between MOS and SeaWiFS: a vicarious intercalibration approach for MOS,” IEEE Trans. Geosci. Remote Sens. 38, 184–197 (2000).
[CrossRef]

O. Dubovik, M. King, “A flexible inversion algorithm for retrieval of aerosol optical properties from Sun and sky radiance measurements,” J. Geophys. Res. 105, (ND16), 20,673–20,6962000.

1999 (1)

1998 (2)

B. Holben, T. Eck, I. Slutsker, D. Tanré, J. P. Buis, A. Setzer, E. Vermote, J. Reagan, Y. Kaufman, T. Nakajima, F. Lavenu, I. Jankowiak, A. Smirnov, “AERONET—a federated instrument network and data archive for aerosol characterization,” Remote Sens. Environ. 66, 1–16 (1998).
[CrossRef]

C. Devaux, A. Vermeulen, J. L. Deuzé, P. Dubuisson, M. Herman, R. Santer, “Retrieval of aerosol single scattering albedo from ground-based measurements: application to observational data,” J. Geophys. Res. 103, 8753–8761 (1998).
[CrossRef]

1996 (2)

1994 (1)

1993 (1)

1990 (1)

D. Tanré, C. Deroo, P. Duhaut, M. Herman, J. Morcrette, J. Perbos, P. Y. Deschamps, “Description of a computer code to simulate the satellite signal in the solar spectrum: 5S code,” Int. J. Remote Sens. 11, 659–668 (1990).
[CrossRef]

1989 (1)

J. L. Deuzé, M. Herman, R. Santer, “Fourier series expansion of the transfer equation in the atmosphere-ocean system,” J. Quant. Spectrosc. Radiat. Transfer 41, 483–494 (1989).
[CrossRef]

1987 (1)

H. R. Gordon, “Calibration requirements and methodology for remote sensors viewing the ocean in the visible,” Remote Sens. Environ. 22, 103–126 (1987).
[CrossRef]

1983 (2)

Barnes, R. A.

R. A. Barnes, R. E. Eplee, F. S. Patt, C. R. McClain, “Changes in the radiometric sensitivity of SeaWiFS determined from lunar and solar-based measurements,” Appl. Opt. 38, 4649–4664 (1999).
[CrossRef]

R. A. Barnes, R. E. Eplee, “The SeaWiFS solar diffuser,” in SeaWiFS Calibration Topics, Part 1, NASA Tech. Memo 104566, 39, R. A. Barnes, E-N. Yeh, R. E. Eplee, eds. (NASA Goddard Space Flight Center, Greenbelt, Md., 1996).

Buis, J. P.

B. Holben, T. Eck, I. Slutsker, D. Tanré, J. P. Buis, A. Setzer, E. Vermote, J. Reagan, Y. Kaufman, T. Nakajima, F. Lavenu, I. Jankowiak, A. Smirnov, “AERONET—a federated instrument network and data archive for aerosol characterization,” Remote Sens. Environ. 66, 1–16 (1998).
[CrossRef]

Deroo, C.

D. Tanré, C. Deroo, P. Duhaut, M. Herman, J. Morcrette, J. Perbos, P. Y. Deschamps, “Description of a computer code to simulate the satellite signal in the solar spectrum: 5S code,” Int. J. Remote Sens. 11, 659–668 (1990).
[CrossRef]

Deschamps, P. Y.

D. Tanré, C. Deroo, P. Duhaut, M. Herman, J. Morcrette, J. Perbos, P. Y. Deschamps, “Description of a computer code to simulate the satellite signal in the solar spectrum: 5S code,” Int. J. Remote Sens. 11, 659–668 (1990).
[CrossRef]

Deuzé, J. L.

C. Devaux, A. Vermeulen, J. L. Deuzé, P. Dubuisson, M. Herman, R. Santer, “Retrieval of aerosol single scattering albedo from ground-based measurements: application to observational data,” J. Geophys. Res. 103, 8753–8761 (1998).
[CrossRef]

J. L. Deuzé, M. Herman, R. Santer, “Fourier series expansion of the transfer equation in the atmosphere-ocean system,” J. Quant. Spectrosc. Radiat. Transfer 41, 483–494 (1989).
[CrossRef]

Devaux, C.

C. Devaux, A. Vermeulen, J. L. Deuzé, P. Dubuisson, M. Herman, R. Santer, “Retrieval of aerosol single scattering albedo from ground-based measurements: application to observational data,” J. Geophys. Res. 103, 8753–8761 (1998).
[CrossRef]

Dubovik, O.

O. Dubovik, M. King, “A flexible inversion algorithm for retrieval of aerosol optical properties from Sun and sky radiance measurements,” J. Geophys. Res. 105, (ND16), 20,673–20,6962000.

Dubuisson, P.

C. Devaux, A. Vermeulen, J. L. Deuzé, P. Dubuisson, M. Herman, R. Santer, “Retrieval of aerosol single scattering albedo from ground-based measurements: application to observational data,” J. Geophys. Res. 103, 8753–8761 (1998).
[CrossRef]

Duhaut, P.

D. Tanré, C. Deroo, P. Duhaut, M. Herman, J. Morcrette, J. Perbos, P. Y. Deschamps, “Description of a computer code to simulate the satellite signal in the solar spectrum: 5S code,” Int. J. Remote Sens. 11, 659–668 (1990).
[CrossRef]

Eck, T.

B. Holben, T. Eck, I. Slutsker, D. Tanré, J. P. Buis, A. Setzer, E. Vermote, J. Reagan, Y. Kaufman, T. Nakajima, F. Lavenu, I. Jankowiak, A. Smirnov, “AERONET—a federated instrument network and data archive for aerosol characterization,” Remote Sens. Environ. 66, 1–16 (1998).
[CrossRef]

Eplee, R. E.

R. A. Barnes, R. E. Eplee, F. S. Patt, C. R. McClain, “Changes in the radiometric sensitivity of SeaWiFS determined from lunar and solar-based measurements,” Appl. Opt. 38, 4649–4664 (1999).
[CrossRef]

R. A. Barnes, R. E. Eplee, “The SeaWiFS solar diffuser,” in SeaWiFS Calibration Topics, Part 1, NASA Tech. Memo 104566, 39, R. A. Barnes, E-N. Yeh, R. E. Eplee, eds. (NASA Goddard Space Flight Center, Greenbelt, Md., 1996).

Fenn, R. W.

E. P. Shettle, R. W. Fenn, “Models of the aerosols of the lower atmosphere and the effects of humidity variations on their optical properties,” Technical Report 0214 (Air Force Geophysical Laboratory, Hanscom Air Force Base, Mass., 1979).

Franz, B.

M. Wang, B. Franz, “Comparing the ocean color measurements between MOS and SeaWiFS: a vicarious intercalibration approach for MOS,” IEEE Trans. Geosci. Remote Sens. 38, 184–197 (2000).
[CrossRef]

Gordon, H. R.

Herman, M.

C. Devaux, A. Vermeulen, J. L. Deuzé, P. Dubuisson, M. Herman, R. Santer, “Retrieval of aerosol single scattering albedo from ground-based measurements: application to observational data,” J. Geophys. Res. 103, 8753–8761 (1998).
[CrossRef]

D. Tanré, C. Deroo, P. Duhaut, M. Herman, J. Morcrette, J. Perbos, P. Y. Deschamps, “Description of a computer code to simulate the satellite signal in the solar spectrum: 5S code,” Int. J. Remote Sens. 11, 659–668 (1990).
[CrossRef]

J. L. Deuzé, M. Herman, R. Santer, “Fourier series expansion of the transfer equation in the atmosphere-ocean system,” J. Quant. Spectrosc. Radiat. Transfer 41, 483–494 (1989).
[CrossRef]

R. Santer, M. Herman, “Particle size distributions from forward scattered light using the Chahine inversion scheme,” Appl. Opt. 22, 2294–2301 (1983).
[CrossRef] [PubMed]

Holben, B.

B. Holben, T. Eck, I. Slutsker, D. Tanré, J. P. Buis, A. Setzer, E. Vermote, J. Reagan, Y. Kaufman, T. Nakajima, F. Lavenu, I. Jankowiak, A. Smirnov, “AERONET—a federated instrument network and data archive for aerosol characterization,” Remote Sens. Environ. 66, 1–16 (1998).
[CrossRef]

Jankowiak, I.

B. Holben, T. Eck, I. Slutsker, D. Tanré, J. P. Buis, A. Setzer, E. Vermote, J. Reagan, Y. Kaufman, T. Nakajima, F. Lavenu, I. Jankowiak, A. Smirnov, “AERONET—a federated instrument network and data archive for aerosol characterization,” Remote Sens. Environ. 66, 1–16 (1998).
[CrossRef]

Kaufman, Y.

B. Holben, T. Eck, I. Slutsker, D. Tanré, J. P. Buis, A. Setzer, E. Vermote, J. Reagan, Y. Kaufman, T. Nakajima, F. Lavenu, I. Jankowiak, A. Smirnov, “AERONET—a federated instrument network and data archive for aerosol characterization,” Remote Sens. Environ. 66, 1–16 (1998).
[CrossRef]

Kieffer, H. H.

H. H. Kieffer, R. L. Widley, “Establishing the moon as a spectral radiance standard,” J. Atmos. Ocean. Technol. 13, 360–375 (1996).
[CrossRef]

King, M.

O. Dubovik, M. King, “A flexible inversion algorithm for retrieval of aerosol optical properties from Sun and sky radiance measurements,” J. Geophys. Res. 105, (ND16), 20,673–20,6962000.

Lavenu, F.

B. Holben, T. Eck, I. Slutsker, D. Tanré, J. P. Buis, A. Setzer, E. Vermote, J. Reagan, Y. Kaufman, T. Nakajima, F. Lavenu, I. Jankowiak, A. Smirnov, “AERONET—a federated instrument network and data archive for aerosol characterization,” Remote Sens. Environ. 66, 1–16 (1998).
[CrossRef]

Martiny, N.

N. Martiny, R. Santer, “Atmospheric corrections over coastal waters for SeaWiFS: validation using ground-based measurements,” in Ocean Optics: Remote Sensing and Underwater Imaging, G. D. Gilbert, R. J. Frouin, eds., Proc. SPIE4488, 184–194 (2002).
[CrossRef]

McClain, C. R.

Morcrette, J.

D. Tanré, C. Deroo, P. Duhaut, M. Herman, J. Morcrette, J. Perbos, P. Y. Deschamps, “Description of a computer code to simulate the satellite signal in the solar spectrum: 5S code,” Int. J. Remote Sens. 11, 659–668 (1990).
[CrossRef]

Nakajima, T.

B. Holben, T. Eck, I. Slutsker, D. Tanré, J. P. Buis, A. Setzer, E. Vermote, J. Reagan, Y. Kaufman, T. Nakajima, F. Lavenu, I. Jankowiak, A. Smirnov, “AERONET—a federated instrument network and data archive for aerosol characterization,” Remote Sens. Environ. 66, 1–16 (1998).
[CrossRef]

T. Nakajima, M. Tanaka, T. Yamauchi, “Retrieval of the optical properties of aerosols from aureole and extinction data,” Appl. Opt. 22, 2951–2959 (1983).
[CrossRef] [PubMed]

Patt, F. S.

Perbos, J.

D. Tanré, C. Deroo, P. Duhaut, M. Herman, J. Morcrette, J. Perbos, P. Y. Deschamps, “Description of a computer code to simulate the satellite signal in the solar spectrum: 5S code,” Int. J. Remote Sens. 11, 659–668 (1990).
[CrossRef]

Reagan, J.

B. Holben, T. Eck, I. Slutsker, D. Tanré, J. P. Buis, A. Setzer, E. Vermote, J. Reagan, Y. Kaufman, T. Nakajima, F. Lavenu, I. Jankowiak, A. Smirnov, “AERONET—a federated instrument network and data archive for aerosol characterization,” Remote Sens. Environ. 66, 1–16 (1998).
[CrossRef]

Santer, R.

C. Devaux, A. Vermeulen, J. L. Deuzé, P. Dubuisson, M. Herman, R. Santer, “Retrieval of aerosol single scattering albedo from ground-based measurements: application to observational data,” J. Geophys. Res. 103, 8753–8761 (1998).
[CrossRef]

J. L. Deuzé, M. Herman, R. Santer, “Fourier series expansion of the transfer equation in the atmosphere-ocean system,” J. Quant. Spectrosc. Radiat. Transfer 41, 483–494 (1989).
[CrossRef]

R. Santer, M. Herman, “Particle size distributions from forward scattered light using the Chahine inversion scheme,” Appl. Opt. 22, 2294–2301 (1983).
[CrossRef] [PubMed]

N. Martiny, R. Santer, “Atmospheric corrections over coastal waters for SeaWiFS: validation using ground-based measurements,” in Ocean Optics: Remote Sensing and Underwater Imaging, G. D. Gilbert, R. J. Frouin, eds., Proc. SPIE4488, 184–194 (2002).
[CrossRef]

Setzer, A.

B. Holben, T. Eck, I. Slutsker, D. Tanré, J. P. Buis, A. Setzer, E. Vermote, J. Reagan, Y. Kaufman, T. Nakajima, F. Lavenu, I. Jankowiak, A. Smirnov, “AERONET—a federated instrument network and data archive for aerosol characterization,” Remote Sens. Environ. 66, 1–16 (1998).
[CrossRef]

Shettle, E. P.

E. P. Shettle, R. W. Fenn, “Models of the aerosols of the lower atmosphere and the effects of humidity variations on their optical properties,” Technical Report 0214 (Air Force Geophysical Laboratory, Hanscom Air Force Base, Mass., 1979).

Slutsker, I.

B. Holben, T. Eck, I. Slutsker, D. Tanré, J. P. Buis, A. Setzer, E. Vermote, J. Reagan, Y. Kaufman, T. Nakajima, F. Lavenu, I. Jankowiak, A. Smirnov, “AERONET—a federated instrument network and data archive for aerosol characterization,” Remote Sens. Environ. 66, 1–16 (1998).
[CrossRef]

Smirnov, A.

B. Holben, T. Eck, I. Slutsker, D. Tanré, J. P. Buis, A. Setzer, E. Vermote, J. Reagan, Y. Kaufman, T. Nakajima, F. Lavenu, I. Jankowiak, A. Smirnov, “AERONET—a federated instrument network and data archive for aerosol characterization,” Remote Sens. Environ. 66, 1–16 (1998).
[CrossRef]

Tanaka, M.

Tanré, D.

B. Holben, T. Eck, I. Slutsker, D. Tanré, J. P. Buis, A. Setzer, E. Vermote, J. Reagan, Y. Kaufman, T. Nakajima, F. Lavenu, I. Jankowiak, A. Smirnov, “AERONET—a federated instrument network and data archive for aerosol characterization,” Remote Sens. Environ. 66, 1–16 (1998).
[CrossRef]

D. Tanré, C. Deroo, P. Duhaut, M. Herman, J. Morcrette, J. Perbos, P. Y. Deschamps, “Description of a computer code to simulate the satellite signal in the solar spectrum: 5S code,” Int. J. Remote Sens. 11, 659–668 (1990).
[CrossRef]

Vermeulen, A.

C. Devaux, A. Vermeulen, J. L. Deuzé, P. Dubuisson, M. Herman, R. Santer, “Retrieval of aerosol single scattering albedo from ground-based measurements: application to observational data,” J. Geophys. Res. 103, 8753–8761 (1998).
[CrossRef]

Vermote, E.

B. Holben, T. Eck, I. Slutsker, D. Tanré, J. P. Buis, A. Setzer, E. Vermote, J. Reagan, Y. Kaufman, T. Nakajima, F. Lavenu, I. Jankowiak, A. Smirnov, “AERONET—a federated instrument network and data archive for aerosol characterization,” Remote Sens. Environ. 66, 1–16 (1998).
[CrossRef]

Wang, M.

Widley, R. L.

H. H. Kieffer, R. L. Widley, “Establishing the moon as a spectral radiance standard,” J. Atmos. Ocean. Technol. 13, 360–375 (1996).
[CrossRef]

Yamauchi, T.

Zhang, T.

Appl. Opt. (6)

IEEE Trans. Geosci. Remote Sens. (1)

M. Wang, B. Franz, “Comparing the ocean color measurements between MOS and SeaWiFS: a vicarious intercalibration approach for MOS,” IEEE Trans. Geosci. Remote Sens. 38, 184–197 (2000).
[CrossRef]

Int. J. Remote Sens. (1)

D. Tanré, C. Deroo, P. Duhaut, M. Herman, J. Morcrette, J. Perbos, P. Y. Deschamps, “Description of a computer code to simulate the satellite signal in the solar spectrum: 5S code,” Int. J. Remote Sens. 11, 659–668 (1990).
[CrossRef]

J. Atmos. Ocean. Technol. (1)

H. H. Kieffer, R. L. Widley, “Establishing the moon as a spectral radiance standard,” J. Atmos. Ocean. Technol. 13, 360–375 (1996).
[CrossRef]

J. Geophys. Res. (2)

O. Dubovik, M. King, “A flexible inversion algorithm for retrieval of aerosol optical properties from Sun and sky radiance measurements,” J. Geophys. Res. 105, (ND16), 20,673–20,6962000.

C. Devaux, A. Vermeulen, J. L. Deuzé, P. Dubuisson, M. Herman, R. Santer, “Retrieval of aerosol single scattering albedo from ground-based measurements: application to observational data,” J. Geophys. Res. 103, 8753–8761 (1998).
[CrossRef]

J. Quant. Spectrosc. Radiat. Transfer (1)

J. L. Deuzé, M. Herman, R. Santer, “Fourier series expansion of the transfer equation in the atmosphere-ocean system,” J. Quant. Spectrosc. Radiat. Transfer 41, 483–494 (1989).
[CrossRef]

Remote Sens. Environ. (2)

B. Holben, T. Eck, I. Slutsker, D. Tanré, J. P. Buis, A. Setzer, E. Vermote, J. Reagan, Y. Kaufman, T. Nakajima, F. Lavenu, I. Jankowiak, A. Smirnov, “AERONET—a federated instrument network and data archive for aerosol characterization,” Remote Sens. Environ. 66, 1–16 (1998).
[CrossRef]

H. R. Gordon, “Calibration requirements and methodology for remote sensors viewing the ocean in the visible,” Remote Sens. Environ. 22, 103–126 (1987).
[CrossRef]

Other (3)

R. A. Barnes, R. E. Eplee, “The SeaWiFS solar diffuser,” in SeaWiFS Calibration Topics, Part 1, NASA Tech. Memo 104566, 39, R. A. Barnes, E-N. Yeh, R. E. Eplee, eds. (NASA Goddard Space Flight Center, Greenbelt, Md., 1996).

E. P. Shettle, R. W. Fenn, “Models of the aerosols of the lower atmosphere and the effects of humidity variations on their optical properties,” Technical Report 0214 (Air Force Geophysical Laboratory, Hanscom Air Force Base, Mass., 1979).

N. Martiny, R. Santer, “Atmospheric corrections over coastal waters for SeaWiFS: validation using ground-based measurements,” in Ocean Optics: Remote Sensing and Underwater Imaging, G. D. Gilbert, R. J. Frouin, eds., Proc. SPIE4488, 184–194 (2002).
[CrossRef]

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Figures (15)

Fig. 1
Fig. 1

Three different measurement protocols for the automatic CIMEL E-318: (a) SUN procedure, (b) ALM, (c) PPL.

Fig. 2
Fig. 2

(a) ●, PPL radiances at λ = 865 nm measured by CIMEL 20 July 1999 over the Venice site for θ s = 34°. We also simulated the sky radiances by using a Junge size distribution (ν = -3.8) with three aerosol refractive indexes: ○, 1.33; □, 1.45; +, 1.55, no absorption. (b) Zoom in the backward scattering.

Fig. 3
Fig. 3

Simulations of PPL radiances measured by CIMEL 31 July 1999 over the Venice site by using aerosol parameters derived with the Dubovik and King method: aerosol phase function and ω0 a = 0.89. θ s = 54°. λ = 865 nm. The relative differences between simulations and measurements versus scattering angle are shown.

Fig. 4
Fig. 4

Simulations of corrective factors f for three Shettle and Fenn aerosol models, M90, T90, and U90, and the three associated Junge slopes ν, -3.2, -4.5, and -4.4. τ a = 0.127. λ = 865 nm. Relative differences are plotted between f for each model: ○, M90; □, T90; △, U90. Two θ s are selected: (a) θ s = 30°, (b) θ s = 60°.

Fig. 5
Fig. 5

Relative differences between f simulated for two Junge slopes (-3.5 and -4.0) at four wavelengths: ○, 443 nm; □, 560 nm; △, 670 nm; +, 865 nm.

Fig. 6
Fig. 6

Same as Fig. 5 but with a Junge slope of -4 and two aerosol refractive indexes (1.33 and 1.45) with no imaginary part.

Fig. 7
Fig. 7

Same as Fig. 6 but with m = 1.45 and two imaginary parts: 0 and -0.02.

Fig. 8
Fig. 8

Influence of the rough sea surface in simulations of PPL radiances at 865 nm. Four wind speeds are considered: □, 2 m/s; △, 5 m/s; ○, 7 m/s; +, 10 m/s. Relative differences between PPL radiances simulated for a flat surface and PPL radiances simulated for a rough surface are represented versus the view zenith angle for three solar zenith angles: (a) 30°, (b) 60°, (c) 75°. The model for the simulation is the T90 model. Visibility is 23 km.

Fig. 9
Fig. 9

Extrapolation of the non-normalized aerosol phase function inverted for the T90 Shettle and Fenn model to as great as 180° by using the corresponding Junge-size distribution with three aerosol refractive indexes (solid curve, 1.33; dashed curve, 1.45; microdashed curve, 1.55).

Fig. 10
Fig. 10

Convergence of the f parameter: (a) M90 model, (b) T90 model, (c) U90 model.

Fig. 11
Fig. 11

Accuracy of the TOA radiance retrieval at 443 nm perpendicular to the principal plane for two solar-zenith angles: □, θ s = 30°; ○, θ s = 60°. The aerosol models are three Shettle and Fenn models: (a) M90, (b) T90, (c) U90. Visibility is 23 km [τ a (550) = 0.24].

Fig. 12
Fig. 12

Influence of the uncertainties on the CIMEL calibration on the TOA radiance retrieval at (a) 865 nm and (b) 443 nm. Relative differences of the TOA radiances when there is an error in the radiance calibration of, open symbols, 2%; and solid symbols, 4%, for two solar-zenith angles: squares, θ s = 30°; circles, θ s = 60°. Visibility is 23 km in both cases.

Fig. 13
Fig. 13

Typical aerosol phase functions derived from radiance measurements collected in Venice 8 June 2000: (a) Solar-zenith angles of the PPL protocols: ○, 53°; □, 42°; +, 72°. (b) The corresponding inverted aerosol phase functions are not normalized.

Fig. 14
Fig. 14

Relative differences between a phase function derived in the morning (5:50 a.m.) and a phase function derived in the afternoon (4:55 p.m.) 20 June 1999 over the Venice site. The derivations are for two wavelengths: □, 865 nm; ○, 670 nm.

Fig. 15
Fig. 15

Histogram of the scattering angles observed on 50 SeaWiFS images for a 2-year period over the Venice site.

Tables (1)

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Table 1 Aerosol Parameters Used for Inversion of Phase Functions 8 June 2000 over the Venice Site

Equations (13)

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LTOA=Latm+tLw
tθ, λ=exp-τrλ2+τo3λ1μtaθ, λ,
taθ, λ=exp-1-Faμ, λτaλμ,
Faμ, λ=14π02π01 PaΘ, λdμdϕ,
Latm1μ, φ=τtotPΘ4μ1+PχPΘrθs+rθv.
αλ1, λ2=lnτaλ1/τaλ2lnλ1/λ2.
nr=dNdr=Crν,
v=α-3.
f=L1LtheoL1Lmes,
PΘ=4L1 expτtotμν1-exp-τtot1μs-1μν-1×μsμν-μs-1,
PΘ=τaPaΘ+τrPrΘτa+τr,
Paμ=l=0 βlplμ,
βl=2l+12-11 Paμplμdμ.

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