Abstract

A combination of sensor calibration error and uncertainty in the solar irradiance can cause very large errors in the computations of the water radiance contribution to the Coastal Zone Color Scanner (CZCS)-measured radiances. This is especially true when the atmospheric correction algorithm is applied in a horizontally inhomogeneous atmosphere. These possible errors can be considerably reduced through spectral measurements of the aerosol optical thickness and upwelled subsurface radiances coincident with a CZCS overpass on a very clear day. For future instruments it is suggested that provision be made for the sensor to view solar irradiance in diffuse reflection. The analysis presented shows that with such a system the error is reduced to a level even below that which would be applicable if the solar irradiance were known precisely.

© 1981 Optical Society of America

Full Article  |  PDF Article

References

  • View by:
  • |
  • |
  • |

  1. W. A. Hovis, D. K. Clark, F. Anderson, R. W. Austin, W. H. Wilson, E. T. Baker, D. Ball, H. R. Gordon, J. L. Mueller, S. Y. El-Sayed, B. Sturm, R. C. Wrigley, C. S. Yentsch, Science 210, 60 (1980).
    [CrossRef] [PubMed]
  2. H. R. Gordon, Appl. Opt. 17, 1631 (1978).
    [CrossRef] [PubMed]
  3. H. R. Gordon, D. K. Clark, Boundary-Layer Meteorol. 18, 299 (1980).
    [CrossRef]
  4. H. R. Gordon, D. K. Clark, J. L. Mueller, W. A. Hovis, Science, 210, 63 (1980).
    [CrossRef] [PubMed]
  5. The signal from the Nimbus-7 CZCS is 8-bit digitized (255 digital numbers between zero and the saturation radiance). A count in this context is one digital number.
  6. These error estimates are only for the purpose of providing a numerical example; however, they are felt to be somewhat realistic. For example, the measurements of Johnson [F. S. Johnson, J. Meteorol. 4, 431 (1954)] and Labs and Neckel, [D. Labs, H. Neckel, Solar Phys. 15, 79 (1970)] differ by about 10% at 440 nm but only about 2% at 670 nm; hence, the δF0/F0 estimate is clearly an upper limit.
    [CrossRef]
  7. The CZCS has an active scan of ~80° centered on nadir. In practice (LR) is nearly constant over the center 40° of the scan (~800 km on the surface).
  8. The data for Orbit 130 were taken at sensor Gain 0. The data for Orbit 296 was taken at Gain 2, but the data in Table II give the counts that would have been obtained for this orbit at Gain 0.
  9. RU stands for radiance unit and here is equivalent to 1 mW/ster μm cm2.
  10. A. Morel, H. R. Gordon, Boundary-Layer Meteorol. 18, 343 (1980).
    [CrossRef]

1980

W. A. Hovis, D. K. Clark, F. Anderson, R. W. Austin, W. H. Wilson, E. T. Baker, D. Ball, H. R. Gordon, J. L. Mueller, S. Y. El-Sayed, B. Sturm, R. C. Wrigley, C. S. Yentsch, Science 210, 60 (1980).
[CrossRef] [PubMed]

H. R. Gordon, D. K. Clark, Boundary-Layer Meteorol. 18, 299 (1980).
[CrossRef]

H. R. Gordon, D. K. Clark, J. L. Mueller, W. A. Hovis, Science, 210, 63 (1980).
[CrossRef] [PubMed]

A. Morel, H. R. Gordon, Boundary-Layer Meteorol. 18, 343 (1980).
[CrossRef]

1978

1954

These error estimates are only for the purpose of providing a numerical example; however, they are felt to be somewhat realistic. For example, the measurements of Johnson [F. S. Johnson, J. Meteorol. 4, 431 (1954)] and Labs and Neckel, [D. Labs, H. Neckel, Solar Phys. 15, 79 (1970)] differ by about 10% at 440 nm but only about 2% at 670 nm; hence, the δF0/F0 estimate is clearly an upper limit.
[CrossRef]

Anderson, F.

W. A. Hovis, D. K. Clark, F. Anderson, R. W. Austin, W. H. Wilson, E. T. Baker, D. Ball, H. R. Gordon, J. L. Mueller, S. Y. El-Sayed, B. Sturm, R. C. Wrigley, C. S. Yentsch, Science 210, 60 (1980).
[CrossRef] [PubMed]

Austin, R. W.

W. A. Hovis, D. K. Clark, F. Anderson, R. W. Austin, W. H. Wilson, E. T. Baker, D. Ball, H. R. Gordon, J. L. Mueller, S. Y. El-Sayed, B. Sturm, R. C. Wrigley, C. S. Yentsch, Science 210, 60 (1980).
[CrossRef] [PubMed]

Baker, E. T.

W. A. Hovis, D. K. Clark, F. Anderson, R. W. Austin, W. H. Wilson, E. T. Baker, D. Ball, H. R. Gordon, J. L. Mueller, S. Y. El-Sayed, B. Sturm, R. C. Wrigley, C. S. Yentsch, Science 210, 60 (1980).
[CrossRef] [PubMed]

Ball, D.

W. A. Hovis, D. K. Clark, F. Anderson, R. W. Austin, W. H. Wilson, E. T. Baker, D. Ball, H. R. Gordon, J. L. Mueller, S. Y. El-Sayed, B. Sturm, R. C. Wrigley, C. S. Yentsch, Science 210, 60 (1980).
[CrossRef] [PubMed]

Clark, D. K.

W. A. Hovis, D. K. Clark, F. Anderson, R. W. Austin, W. H. Wilson, E. T. Baker, D. Ball, H. R. Gordon, J. L. Mueller, S. Y. El-Sayed, B. Sturm, R. C. Wrigley, C. S. Yentsch, Science 210, 60 (1980).
[CrossRef] [PubMed]

H. R. Gordon, D. K. Clark, Boundary-Layer Meteorol. 18, 299 (1980).
[CrossRef]

H. R. Gordon, D. K. Clark, J. L. Mueller, W. A. Hovis, Science, 210, 63 (1980).
[CrossRef] [PubMed]

El-Sayed, S. Y.

W. A. Hovis, D. K. Clark, F. Anderson, R. W. Austin, W. H. Wilson, E. T. Baker, D. Ball, H. R. Gordon, J. L. Mueller, S. Y. El-Sayed, B. Sturm, R. C. Wrigley, C. S. Yentsch, Science 210, 60 (1980).
[CrossRef] [PubMed]

Gordon, H. R.

H. R. Gordon, D. K. Clark, J. L. Mueller, W. A. Hovis, Science, 210, 63 (1980).
[CrossRef] [PubMed]

H. R. Gordon, D. K. Clark, Boundary-Layer Meteorol. 18, 299 (1980).
[CrossRef]

W. A. Hovis, D. K. Clark, F. Anderson, R. W. Austin, W. H. Wilson, E. T. Baker, D. Ball, H. R. Gordon, J. L. Mueller, S. Y. El-Sayed, B. Sturm, R. C. Wrigley, C. S. Yentsch, Science 210, 60 (1980).
[CrossRef] [PubMed]

A. Morel, H. R. Gordon, Boundary-Layer Meteorol. 18, 343 (1980).
[CrossRef]

H. R. Gordon, Appl. Opt. 17, 1631 (1978).
[CrossRef] [PubMed]

Hovis, W. A.

W. A. Hovis, D. K. Clark, F. Anderson, R. W. Austin, W. H. Wilson, E. T. Baker, D. Ball, H. R. Gordon, J. L. Mueller, S. Y. El-Sayed, B. Sturm, R. C. Wrigley, C. S. Yentsch, Science 210, 60 (1980).
[CrossRef] [PubMed]

H. R. Gordon, D. K. Clark, J. L. Mueller, W. A. Hovis, Science, 210, 63 (1980).
[CrossRef] [PubMed]

Johnson, F. S.

These error estimates are only for the purpose of providing a numerical example; however, they are felt to be somewhat realistic. For example, the measurements of Johnson [F. S. Johnson, J. Meteorol. 4, 431 (1954)] and Labs and Neckel, [D. Labs, H. Neckel, Solar Phys. 15, 79 (1970)] differ by about 10% at 440 nm but only about 2% at 670 nm; hence, the δF0/F0 estimate is clearly an upper limit.
[CrossRef]

Morel, A.

A. Morel, H. R. Gordon, Boundary-Layer Meteorol. 18, 343 (1980).
[CrossRef]

Mueller, J. L.

H. R. Gordon, D. K. Clark, J. L. Mueller, W. A. Hovis, Science, 210, 63 (1980).
[CrossRef] [PubMed]

W. A. Hovis, D. K. Clark, F. Anderson, R. W. Austin, W. H. Wilson, E. T. Baker, D. Ball, H. R. Gordon, J. L. Mueller, S. Y. El-Sayed, B. Sturm, R. C. Wrigley, C. S. Yentsch, Science 210, 60 (1980).
[CrossRef] [PubMed]

Sturm, B.

W. A. Hovis, D. K. Clark, F. Anderson, R. W. Austin, W. H. Wilson, E. T. Baker, D. Ball, H. R. Gordon, J. L. Mueller, S. Y. El-Sayed, B. Sturm, R. C. Wrigley, C. S. Yentsch, Science 210, 60 (1980).
[CrossRef] [PubMed]

Wilson, W. H.

W. A. Hovis, D. K. Clark, F. Anderson, R. W. Austin, W. H. Wilson, E. T. Baker, D. Ball, H. R. Gordon, J. L. Mueller, S. Y. El-Sayed, B. Sturm, R. C. Wrigley, C. S. Yentsch, Science 210, 60 (1980).
[CrossRef] [PubMed]

Wrigley, R. C.

W. A. Hovis, D. K. Clark, F. Anderson, R. W. Austin, W. H. Wilson, E. T. Baker, D. Ball, H. R. Gordon, J. L. Mueller, S. Y. El-Sayed, B. Sturm, R. C. Wrigley, C. S. Yentsch, Science 210, 60 (1980).
[CrossRef] [PubMed]

Yentsch, C. S.

W. A. Hovis, D. K. Clark, F. Anderson, R. W. Austin, W. H. Wilson, E. T. Baker, D. Ball, H. R. Gordon, J. L. Mueller, S. Y. El-Sayed, B. Sturm, R. C. Wrigley, C. S. Yentsch, Science 210, 60 (1980).
[CrossRef] [PubMed]

Appl. Opt.

Boundary-Layer Meteorol.

H. R. Gordon, D. K. Clark, Boundary-Layer Meteorol. 18, 299 (1980).
[CrossRef]

A. Morel, H. R. Gordon, Boundary-Layer Meteorol. 18, 343 (1980).
[CrossRef]

J. Meteorol.

These error estimates are only for the purpose of providing a numerical example; however, they are felt to be somewhat realistic. For example, the measurements of Johnson [F. S. Johnson, J. Meteorol. 4, 431 (1954)] and Labs and Neckel, [D. Labs, H. Neckel, Solar Phys. 15, 79 (1970)] differ by about 10% at 440 nm but only about 2% at 670 nm; hence, the δF0/F0 estimate is clearly an upper limit.
[CrossRef]

Science

H. R. Gordon, D. K. Clark, J. L. Mueller, W. A. Hovis, Science, 210, 63 (1980).
[CrossRef] [PubMed]

W. A. Hovis, D. K. Clark, F. Anderson, R. W. Austin, W. H. Wilson, E. T. Baker, D. Ball, H. R. Gordon, J. L. Mueller, S. Y. El-Sayed, B. Sturm, R. C. Wrigley, C. S. Yentsch, Science 210, 60 (1980).
[CrossRef] [PubMed]

Other

The signal from the Nimbus-7 CZCS is 8-bit digitized (255 digital numbers between zero and the saturation radiance). A count in this context is one digital number.

The CZCS has an active scan of ~80° centered on nadir. In practice (LR) is nearly constant over the center 40° of the scan (~800 km on the surface).

The data for Orbit 130 were taken at sensor Gain 0. The data for Orbit 296 was taken at Gain 2, but the data in Table II give the counts that would have been obtained for this orbit at Gain 0.

RU stands for radiance unit and here is equivalent to 1 mW/ster μm cm2.

Cited By

OSA participates in CrossRef's Cited-By Linking service. Citing articles from OSA journals and other participating publishers are listed here.

Alert me when this article is cited.


Tables (2)

Tables Icon

Table I List of Symbols

Tables Icon

Table II Sample CZCS Radiances in Gain 0 Counts For Turbid and Typical Atmospheric Conditions

Equations (22)

Equations on this page are rendered with MathJax. Learn more.

( L W ) + ( L A ) = ( L T ) - ( L R ) .
δ L T - δ L R δ L A + δ L W δ L T + δ L R .
δ L T / ( L T ) = α ,
δ L R = I R δ F 0 = ( L R ) δ F 0 F 0 .
( L W λ ) = ( L T λ ) - ( L R λ ) - S ( λ , λ 0 ) [ ( L T λ 0 ) - ( L R λ 0 ) ] ,
( L W λ ) = ( L T λ ) - ( L R λ ) - [ ( L T λ 0 ) - ( L R λ 0 ) ( L T λ 0 ) - ( L R λ 0 ) ] [ ( L T λ ) - ( L R λ ) - ( L W λ ) ] ,
( κ ) ( L T λ 0 ) - ( L R λ 0 ) ( L T λ 0 ) - ( L R λ 0 ) = ( L A λ 0 ) ( L A λ 0 )
δ L W λ = ( L W λ - L W λ ) α λ .
F 0 = ( L R C ) + δ L R C I R C .
L R = [ ( L R C ) + δ L R C ] I R / I R C ,             or L R = ( L R ) + I R δ L R C I R C .
δ L A + δ L W = ( L T ) [ δ L T ( L T ) - δ L R C ( L R C ) ] + [ ( L A ) + ( L W ) ] δ L R C ( L R C ) .
δ L A + δ L W [ ( L A ) + ( L W ) ] α ,
δ L A + δ L W = δ L T = ( L T ) α ,
δ L W λ = [ ( L W λ ) - ( κ ) ( L W λ ) ] α λ .
( I A ) + ( I W ) = ( I T ) - ( I R )
( L A ) + ( L W ) = [ ( I T ) - ( I R ) ] F 0 = [ ( I T ) - ( I R ) ] ( L D ) R .
L D = ( L D ) + δ L D , L T = ( L T ) + δ L T .
δ L A + δ L W = [ ( L A ) + ( L W ) ] δ L D ( L D ) + ( L T ) [ δ L T ( L T ) - δ L D ( L D ) ] ,
( L D ) = R F 0 .
L R = F 0 ( I R ) = ( L R ) + δ L D R I R ,
δ L A + δ L W = δ L T - ( L R ) δ L D L D .
δ L A + δ L W α [ ( L A ) + ( L W ) ] .

Metrics