Abstract

Passive infrared remote detection of hazardous gases, vapors, and aerosols is based on the difference, ΔT, between the air temperature of the threat vapor cloud and the effective radiative temperature of the background. In this paper I address the problem of detection with a low-angle-sky background. I used modtran to predict ΔT and atmospheric transmittance for standard atmospheric models. The detection limits, at 2-cm−1 resolution, are discussed for sulfur hexafluoride, Sarin, trichloroethylene, methyl isocyanate, mustard gas, methyl chloride, and sulfur dioxide for selected cases with the U.S. Standard, the Subarctic Winter, and the Tropical models. I used a particularly interesting case of Sarin detection with the Subarctic Winter atmospheric model to illustrate the power of modtran to predict subtle changes in ΔT with angle of elevation (AOE).

© 1996 Optical Society of America

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References

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  1. J. P. Carrico, “The DOD chemical-biological stand-off detection program: a revisit nearly ten years later,” presented at the Third Workshop on Stand-Off Detection for Chemical and Biological Defense, Williamsburg, Va., 17–21 October 1994.
  2. D. F. Flanigan, “Detection of organic vapors with active and passive sensors: a comparison,” Appl. Opt. 25, 4253–4260 (1986).
    [CrossRef] [PubMed]
  3. A. Berk, L. S. Bernstein, D. C. Robertson, “modtran: A Moderate Resolution Model for lowtran 7,” GL-TR-89-0122, AD-A214-337 (Geophysics Laboratory, Hanscom Air Force Base, Mass. 01731-5000).
  4. F. Kneizys, E. Shettle, L. Abreu, J. Chetwynd, G. Anderson, W. Gallery, J. Selby, S. Clough, Users Guide to lowtran 7, AFGL-TR-88-0177. (U.S. Air Force Geophysics Laboratory, Hanscom Air Force Base, Mass., 1988).
  5. F. X. Kneizys, E. P. Shettle, W. O. Gallery, J. H. Chetwynd, L. W. Abreu, J. E. A. Selby, S. A. Clough, R. W. Fenn, Atmospheric Transmittance/Radiance Computer Code lowtran 6,” AFGL-TR-83-0187 (U.S. Air Force Geophysics Laboratory, Hanscom Air Force Base, Mass., 1983).
  6. D. Flanigan, J. Astarita, “Low angle sky ΔT from modtran atmospheric models,” presented at the Third Workshop on Stand-Off Detection for Chemical and Biological Defense, Williamsburg, Va., 17–21 October 1994 (STC Corporation, 101 Research Drive, Hampton, Va. 23666-1340).
  7. D. Flanigan, “Vapor-detection sensitivity as a function of spectral resolution for a single Lorentzian band,” Appl. Opt. 34, 2636–2639 (1995).
    [CrossRef] [PubMed]
  8. S. Wolfram, Mathematica, A System for Doing Mathematics by Computer, 2nd ed. (Addison-Wesley, Reading, Mass., 1991).
  9. D. W. Wilmot, W. R. Owens, R. J. Shelton, “Warning systems,” in The Infrared and Electro-Optical Systems Handbook, Vol 7 (SPIE, Bellingham, Wash., 1993), pp. 57–61.
  10. D. Flanigan, “Discrepancies between two formulations of signal-to-noise ratio for background limited detection,” Appl. Opt. 34, 2721–2723 (1995).
    [CrossRef] [PubMed]
  11. T. Quinn, “Radiometric sensitivity comparison between LSCADS and XM21 sensors,” presented at the Third Workshop on Stand-Off Detection for Chemical and Biological Defense, Williamsburg, Va., 17–21 October 1994.
  12. R. Beer, Remote Sensing by Fourier Transform Spectroscopy (Wiley, New York, 1992), p. 65.
  13. J. Connes, “Spectroscopic studies using Fourier transformations,” Rev. Opt. 4, 2–3 (1963); p. 3 of English translation: document AD 409869, Clearinghouse for Federal Scientific and Technical Information, Cameron Station, Va.
  14. W. B. Davenport, W. L. Root, An Introduction to Random Signals and Noise (IEEE, New York, 1987), p. 145.
  15. B. R. Frieden, Probability, Statistical Optics, and Data Testing (Springer-Verlag, New York, 1991).
    [CrossRef]
  16. D. Flanigan, “Chamber Optics for Testing Passive Remote Sensing Vapor Detectors,” ERDEC-TR-127 (Edgewood Research, Development, and Engineering Center, November1993). Available from the author or the Clearinghouse for Federal Scientific and Technical Information, Cameron Station, Va.
  17. J. R. Pierce, An Introduction to Information Theory, Symbols, Signals, and Noise (Dover, New York, 1980), p. 49.
  18. M. L. Polak, D. K. Stone, G. J. Scherer, G. N. Harper, M. A. Rocha, K. C. Herr, Application of the M21 to Chemical Remote Sensing, Aerospace Report No. TOR-95 (5705)-1 (Engineering and Technology Group, The Aerospace Corp., El Segundo, Calif., 1994).
  19. R. J. Combs, D. F. Flanigan, R. B. Knapp, “Responsivity of an infrared Fourier transform spectroradiometer,” presented at Pittcon ’93, Chicago, Ill., March 1993.
  20. Commercially available data from P. L. Hanst and S. T. Hanst, Infrared Analysis, Inc., 1424 N. Central Park Ave., Anaheim, Calif. 92802.
  21. W. J. Barrett, E. B. Dismukes, Infrared Spectral Studies of Agents and Field Contaminants, First Annual Report, contract DAAA15-68-C-0154 (Clearinghouse for Federal Scientific and Technical Information, Cameron Station, Va., 1969).

1995 (2)

1986 (1)

1963 (1)

J. Connes, “Spectroscopic studies using Fourier transformations,” Rev. Opt. 4, 2–3 (1963); p. 3 of English translation: document AD 409869, Clearinghouse for Federal Scientific and Technical Information, Cameron Station, Va.

Abreu, L.

F. Kneizys, E. Shettle, L. Abreu, J. Chetwynd, G. Anderson, W. Gallery, J. Selby, S. Clough, Users Guide to lowtran 7, AFGL-TR-88-0177. (U.S. Air Force Geophysics Laboratory, Hanscom Air Force Base, Mass., 1988).

Abreu, L. W.

F. X. Kneizys, E. P. Shettle, W. O. Gallery, J. H. Chetwynd, L. W. Abreu, J. E. A. Selby, S. A. Clough, R. W. Fenn, Atmospheric Transmittance/Radiance Computer Code lowtran 6,” AFGL-TR-83-0187 (U.S. Air Force Geophysics Laboratory, Hanscom Air Force Base, Mass., 1983).

Anderson, G.

F. Kneizys, E. Shettle, L. Abreu, J. Chetwynd, G. Anderson, W. Gallery, J. Selby, S. Clough, Users Guide to lowtran 7, AFGL-TR-88-0177. (U.S. Air Force Geophysics Laboratory, Hanscom Air Force Base, Mass., 1988).

Astarita, J.

D. Flanigan, J. Astarita, “Low angle sky ΔT from modtran atmospheric models,” presented at the Third Workshop on Stand-Off Detection for Chemical and Biological Defense, Williamsburg, Va., 17–21 October 1994 (STC Corporation, 101 Research Drive, Hampton, Va. 23666-1340).

Barrett, W. J.

W. J. Barrett, E. B. Dismukes, Infrared Spectral Studies of Agents and Field Contaminants, First Annual Report, contract DAAA15-68-C-0154 (Clearinghouse for Federal Scientific and Technical Information, Cameron Station, Va., 1969).

Beer, R.

R. Beer, Remote Sensing by Fourier Transform Spectroscopy (Wiley, New York, 1992), p. 65.

Berk, A.

A. Berk, L. S. Bernstein, D. C. Robertson, “modtran: A Moderate Resolution Model for lowtran 7,” GL-TR-89-0122, AD-A214-337 (Geophysics Laboratory, Hanscom Air Force Base, Mass. 01731-5000).

Bernstein, L. S.

A. Berk, L. S. Bernstein, D. C. Robertson, “modtran: A Moderate Resolution Model for lowtran 7,” GL-TR-89-0122, AD-A214-337 (Geophysics Laboratory, Hanscom Air Force Base, Mass. 01731-5000).

Carrico, J. P.

J. P. Carrico, “The DOD chemical-biological stand-off detection program: a revisit nearly ten years later,” presented at the Third Workshop on Stand-Off Detection for Chemical and Biological Defense, Williamsburg, Va., 17–21 October 1994.

Chetwynd, J.

F. Kneizys, E. Shettle, L. Abreu, J. Chetwynd, G. Anderson, W. Gallery, J. Selby, S. Clough, Users Guide to lowtran 7, AFGL-TR-88-0177. (U.S. Air Force Geophysics Laboratory, Hanscom Air Force Base, Mass., 1988).

Chetwynd, J. H.

F. X. Kneizys, E. P. Shettle, W. O. Gallery, J. H. Chetwynd, L. W. Abreu, J. E. A. Selby, S. A. Clough, R. W. Fenn, Atmospheric Transmittance/Radiance Computer Code lowtran 6,” AFGL-TR-83-0187 (U.S. Air Force Geophysics Laboratory, Hanscom Air Force Base, Mass., 1983).

Clough, S.

F. Kneizys, E. Shettle, L. Abreu, J. Chetwynd, G. Anderson, W. Gallery, J. Selby, S. Clough, Users Guide to lowtran 7, AFGL-TR-88-0177. (U.S. Air Force Geophysics Laboratory, Hanscom Air Force Base, Mass., 1988).

Clough, S. A.

F. X. Kneizys, E. P. Shettle, W. O. Gallery, J. H. Chetwynd, L. W. Abreu, J. E. A. Selby, S. A. Clough, R. W. Fenn, Atmospheric Transmittance/Radiance Computer Code lowtran 6,” AFGL-TR-83-0187 (U.S. Air Force Geophysics Laboratory, Hanscom Air Force Base, Mass., 1983).

Combs, R. J.

R. J. Combs, D. F. Flanigan, R. B. Knapp, “Responsivity of an infrared Fourier transform spectroradiometer,” presented at Pittcon ’93, Chicago, Ill., March 1993.

Connes, J.

J. Connes, “Spectroscopic studies using Fourier transformations,” Rev. Opt. 4, 2–3 (1963); p. 3 of English translation: document AD 409869, Clearinghouse for Federal Scientific and Technical Information, Cameron Station, Va.

Davenport, W. B.

W. B. Davenport, W. L. Root, An Introduction to Random Signals and Noise (IEEE, New York, 1987), p. 145.

Dismukes, E. B.

W. J. Barrett, E. B. Dismukes, Infrared Spectral Studies of Agents and Field Contaminants, First Annual Report, contract DAAA15-68-C-0154 (Clearinghouse for Federal Scientific and Technical Information, Cameron Station, Va., 1969).

Fenn, R. W.

F. X. Kneizys, E. P. Shettle, W. O. Gallery, J. H. Chetwynd, L. W. Abreu, J. E. A. Selby, S. A. Clough, R. W. Fenn, Atmospheric Transmittance/Radiance Computer Code lowtran 6,” AFGL-TR-83-0187 (U.S. Air Force Geophysics Laboratory, Hanscom Air Force Base, Mass., 1983).

Flanigan, D.

D. Flanigan, “Vapor-detection sensitivity as a function of spectral resolution for a single Lorentzian band,” Appl. Opt. 34, 2636–2639 (1995).
[CrossRef] [PubMed]

D. Flanigan, “Discrepancies between two formulations of signal-to-noise ratio for background limited detection,” Appl. Opt. 34, 2721–2723 (1995).
[CrossRef] [PubMed]

D. Flanigan, J. Astarita, “Low angle sky ΔT from modtran atmospheric models,” presented at the Third Workshop on Stand-Off Detection for Chemical and Biological Defense, Williamsburg, Va., 17–21 October 1994 (STC Corporation, 101 Research Drive, Hampton, Va. 23666-1340).

D. Flanigan, “Chamber Optics for Testing Passive Remote Sensing Vapor Detectors,” ERDEC-TR-127 (Edgewood Research, Development, and Engineering Center, November1993). Available from the author or the Clearinghouse for Federal Scientific and Technical Information, Cameron Station, Va.

Flanigan, D. F.

D. F. Flanigan, “Detection of organic vapors with active and passive sensors: a comparison,” Appl. Opt. 25, 4253–4260 (1986).
[CrossRef] [PubMed]

R. J. Combs, D. F. Flanigan, R. B. Knapp, “Responsivity of an infrared Fourier transform spectroradiometer,” presented at Pittcon ’93, Chicago, Ill., March 1993.

Frieden, B. R.

B. R. Frieden, Probability, Statistical Optics, and Data Testing (Springer-Verlag, New York, 1991).
[CrossRef]

Gallery, W.

F. Kneizys, E. Shettle, L. Abreu, J. Chetwynd, G. Anderson, W. Gallery, J. Selby, S. Clough, Users Guide to lowtran 7, AFGL-TR-88-0177. (U.S. Air Force Geophysics Laboratory, Hanscom Air Force Base, Mass., 1988).

Gallery, W. O.

F. X. Kneizys, E. P. Shettle, W. O. Gallery, J. H. Chetwynd, L. W. Abreu, J. E. A. Selby, S. A. Clough, R. W. Fenn, Atmospheric Transmittance/Radiance Computer Code lowtran 6,” AFGL-TR-83-0187 (U.S. Air Force Geophysics Laboratory, Hanscom Air Force Base, Mass., 1983).

Harper, G. N.

M. L. Polak, D. K. Stone, G. J. Scherer, G. N. Harper, M. A. Rocha, K. C. Herr, Application of the M21 to Chemical Remote Sensing, Aerospace Report No. TOR-95 (5705)-1 (Engineering and Technology Group, The Aerospace Corp., El Segundo, Calif., 1994).

Herr, K. C.

M. L. Polak, D. K. Stone, G. J. Scherer, G. N. Harper, M. A. Rocha, K. C. Herr, Application of the M21 to Chemical Remote Sensing, Aerospace Report No. TOR-95 (5705)-1 (Engineering and Technology Group, The Aerospace Corp., El Segundo, Calif., 1994).

Knapp, R. B.

R. J. Combs, D. F. Flanigan, R. B. Knapp, “Responsivity of an infrared Fourier transform spectroradiometer,” presented at Pittcon ’93, Chicago, Ill., March 1993.

Kneizys, F.

F. Kneizys, E. Shettle, L. Abreu, J. Chetwynd, G. Anderson, W. Gallery, J. Selby, S. Clough, Users Guide to lowtran 7, AFGL-TR-88-0177. (U.S. Air Force Geophysics Laboratory, Hanscom Air Force Base, Mass., 1988).

Kneizys, F. X.

F. X. Kneizys, E. P. Shettle, W. O. Gallery, J. H. Chetwynd, L. W. Abreu, J. E. A. Selby, S. A. Clough, R. W. Fenn, Atmospheric Transmittance/Radiance Computer Code lowtran 6,” AFGL-TR-83-0187 (U.S. Air Force Geophysics Laboratory, Hanscom Air Force Base, Mass., 1983).

Owens, W. R.

D. W. Wilmot, W. R. Owens, R. J. Shelton, “Warning systems,” in The Infrared and Electro-Optical Systems Handbook, Vol 7 (SPIE, Bellingham, Wash., 1993), pp. 57–61.

Pierce, J. R.

J. R. Pierce, An Introduction to Information Theory, Symbols, Signals, and Noise (Dover, New York, 1980), p. 49.

Polak, M. L.

M. L. Polak, D. K. Stone, G. J. Scherer, G. N. Harper, M. A. Rocha, K. C. Herr, Application of the M21 to Chemical Remote Sensing, Aerospace Report No. TOR-95 (5705)-1 (Engineering and Technology Group, The Aerospace Corp., El Segundo, Calif., 1994).

Quinn, T.

T. Quinn, “Radiometric sensitivity comparison between LSCADS and XM21 sensors,” presented at the Third Workshop on Stand-Off Detection for Chemical and Biological Defense, Williamsburg, Va., 17–21 October 1994.

Robertson, D. C.

A. Berk, L. S. Bernstein, D. C. Robertson, “modtran: A Moderate Resolution Model for lowtran 7,” GL-TR-89-0122, AD-A214-337 (Geophysics Laboratory, Hanscom Air Force Base, Mass. 01731-5000).

Rocha, M. A.

M. L. Polak, D. K. Stone, G. J. Scherer, G. N. Harper, M. A. Rocha, K. C. Herr, Application of the M21 to Chemical Remote Sensing, Aerospace Report No. TOR-95 (5705)-1 (Engineering and Technology Group, The Aerospace Corp., El Segundo, Calif., 1994).

Root, W. L.

W. B. Davenport, W. L. Root, An Introduction to Random Signals and Noise (IEEE, New York, 1987), p. 145.

Scherer, G. J.

M. L. Polak, D. K. Stone, G. J. Scherer, G. N. Harper, M. A. Rocha, K. C. Herr, Application of the M21 to Chemical Remote Sensing, Aerospace Report No. TOR-95 (5705)-1 (Engineering and Technology Group, The Aerospace Corp., El Segundo, Calif., 1994).

Selby, J.

F. Kneizys, E. Shettle, L. Abreu, J. Chetwynd, G. Anderson, W. Gallery, J. Selby, S. Clough, Users Guide to lowtran 7, AFGL-TR-88-0177. (U.S. Air Force Geophysics Laboratory, Hanscom Air Force Base, Mass., 1988).

Selby, J. E. A.

F. X. Kneizys, E. P. Shettle, W. O. Gallery, J. H. Chetwynd, L. W. Abreu, J. E. A. Selby, S. A. Clough, R. W. Fenn, Atmospheric Transmittance/Radiance Computer Code lowtran 6,” AFGL-TR-83-0187 (U.S. Air Force Geophysics Laboratory, Hanscom Air Force Base, Mass., 1983).

Shelton, R. J.

D. W. Wilmot, W. R. Owens, R. J. Shelton, “Warning systems,” in The Infrared and Electro-Optical Systems Handbook, Vol 7 (SPIE, Bellingham, Wash., 1993), pp. 57–61.

Shettle, E.

F. Kneizys, E. Shettle, L. Abreu, J. Chetwynd, G. Anderson, W. Gallery, J. Selby, S. Clough, Users Guide to lowtran 7, AFGL-TR-88-0177. (U.S. Air Force Geophysics Laboratory, Hanscom Air Force Base, Mass., 1988).

Shettle, E. P.

F. X. Kneizys, E. P. Shettle, W. O. Gallery, J. H. Chetwynd, L. W. Abreu, J. E. A. Selby, S. A. Clough, R. W. Fenn, Atmospheric Transmittance/Radiance Computer Code lowtran 6,” AFGL-TR-83-0187 (U.S. Air Force Geophysics Laboratory, Hanscom Air Force Base, Mass., 1983).

Stone, D. K.

M. L. Polak, D. K. Stone, G. J. Scherer, G. N. Harper, M. A. Rocha, K. C. Herr, Application of the M21 to Chemical Remote Sensing, Aerospace Report No. TOR-95 (5705)-1 (Engineering and Technology Group, The Aerospace Corp., El Segundo, Calif., 1994).

Wilmot, D. W.

D. W. Wilmot, W. R. Owens, R. J. Shelton, “Warning systems,” in The Infrared and Electro-Optical Systems Handbook, Vol 7 (SPIE, Bellingham, Wash., 1993), pp. 57–61.

Wolfram, S.

S. Wolfram, Mathematica, A System for Doing Mathematics by Computer, 2nd ed. (Addison-Wesley, Reading, Mass., 1991).

Appl. Opt. (3)

Rev. Opt. (1)

J. Connes, “Spectroscopic studies using Fourier transformations,” Rev. Opt. 4, 2–3 (1963); p. 3 of English translation: document AD 409869, Clearinghouse for Federal Scientific and Technical Information, Cameron Station, Va.

Other (17)

W. B. Davenport, W. L. Root, An Introduction to Random Signals and Noise (IEEE, New York, 1987), p. 145.

B. R. Frieden, Probability, Statistical Optics, and Data Testing (Springer-Verlag, New York, 1991).
[CrossRef]

D. Flanigan, “Chamber Optics for Testing Passive Remote Sensing Vapor Detectors,” ERDEC-TR-127 (Edgewood Research, Development, and Engineering Center, November1993). Available from the author or the Clearinghouse for Federal Scientific and Technical Information, Cameron Station, Va.

J. R. Pierce, An Introduction to Information Theory, Symbols, Signals, and Noise (Dover, New York, 1980), p. 49.

M. L. Polak, D. K. Stone, G. J. Scherer, G. N. Harper, M. A. Rocha, K. C. Herr, Application of the M21 to Chemical Remote Sensing, Aerospace Report No. TOR-95 (5705)-1 (Engineering and Technology Group, The Aerospace Corp., El Segundo, Calif., 1994).

R. J. Combs, D. F. Flanigan, R. B. Knapp, “Responsivity of an infrared Fourier transform spectroradiometer,” presented at Pittcon ’93, Chicago, Ill., March 1993.

Commercially available data from P. L. Hanst and S. T. Hanst, Infrared Analysis, Inc., 1424 N. Central Park Ave., Anaheim, Calif. 92802.

W. J. Barrett, E. B. Dismukes, Infrared Spectral Studies of Agents and Field Contaminants, First Annual Report, contract DAAA15-68-C-0154 (Clearinghouse for Federal Scientific and Technical Information, Cameron Station, Va., 1969).

T. Quinn, “Radiometric sensitivity comparison between LSCADS and XM21 sensors,” presented at the Third Workshop on Stand-Off Detection for Chemical and Biological Defense, Williamsburg, Va., 17–21 October 1994.

R. Beer, Remote Sensing by Fourier Transform Spectroscopy (Wiley, New York, 1992), p. 65.

S. Wolfram, Mathematica, A System for Doing Mathematics by Computer, 2nd ed. (Addison-Wesley, Reading, Mass., 1991).

D. W. Wilmot, W. R. Owens, R. J. Shelton, “Warning systems,” in The Infrared and Electro-Optical Systems Handbook, Vol 7 (SPIE, Bellingham, Wash., 1993), pp. 57–61.

A. Berk, L. S. Bernstein, D. C. Robertson, “modtran: A Moderate Resolution Model for lowtran 7,” GL-TR-89-0122, AD-A214-337 (Geophysics Laboratory, Hanscom Air Force Base, Mass. 01731-5000).

F. Kneizys, E. Shettle, L. Abreu, J. Chetwynd, G. Anderson, W. Gallery, J. Selby, S. Clough, Users Guide to lowtran 7, AFGL-TR-88-0177. (U.S. Air Force Geophysics Laboratory, Hanscom Air Force Base, Mass., 1988).

F. X. Kneizys, E. P. Shettle, W. O. Gallery, J. H. Chetwynd, L. W. Abreu, J. E. A. Selby, S. A. Clough, R. W. Fenn, Atmospheric Transmittance/Radiance Computer Code lowtran 6,” AFGL-TR-83-0187 (U.S. Air Force Geophysics Laboratory, Hanscom Air Force Base, Mass., 1983).

D. Flanigan, J. Astarita, “Low angle sky ΔT from modtran atmospheric models,” presented at the Third Workshop on Stand-Off Detection for Chemical and Biological Defense, Williamsburg, Va., 17–21 October 1994 (STC Corporation, 101 Research Drive, Hampton, Va. 23666-1340).

J. P. Carrico, “The DOD chemical-biological stand-off detection program: a revisit nearly ten years later,” presented at the Third Workshop on Stand-Off Detection for Chemical and Biological Defense, Williamsburg, Va., 17–21 October 1994.

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Figures (33)

Fig. 1
Fig. 1

Temperature (x axis) as a function of altitude (y axis) for the U.S. Standard Atmosphere model.

Fig. 2
Fig. 2

Penetration of a tangential ray into the upper atmosphere.

Fig. 3
Fig. 3

Three-layer model.

Fig. 4
Fig. 4

NEΔT for the U.S. Standard Atmosphere with sensor parameters given in Table 1.

Fig. 5
Fig. 5

Absorptivity of SF6.

Fig. 6
Fig. 6

ΔL for the U.S. Standard Atmosphere at 0° AOE.

Fig. 7
Fig. 7

ΔL from Fig. 6 plus a target cloud of SF6 at a CL = 1000 mg/m2 (164 parts in 106 m).

Fig. 8
Fig. 8

Δ2L for the spectra in Figs. 6 and 7.

Fig. 9
Fig. 9

Δ2T for the spectra in Fig. 8.

Fig. 10
Fig. 10

Figure 9 plus noise (1/60-s integration time).

Fig. 11
Fig. 11

Absorptivity of GB vapor.

Fig. 12
Fig. 12

Δ2T for the U.S. Standard Atmosphere at 0° AOE and 90 mg/m2 (15 parts in 106 m) of GB.

Fig. 13
Fig. 13

Figure 12 plus noise (1-s integration time).

Fig. 14
Fig. 14

Δ2T for conditions shown in Fig. 13 when the AOE is raised to 1°.

Fig. 15
Fig. 15

Temperature profile for the Subarctic Winter atmospheric model.

Fig. 16
Fig. 16

ΔL spectrum for the Subarctic Winter model at 0° AOE.

Fig. 17
Fig. 17

Δ2T for the Subarctic Winter model at 0° AOE and 90 mg/m2 (15 parts in 106 m) of GB.

Fig. 18
Fig. 18

Figure 17 plus noise (60-s integration time).

Fig. 19
Fig. 19

Δ2T for the Subarctic Winter model at 1° AOE and 90 mg/m2 (15 parts in 106 m) of GB.

Fig. 20
Fig. 20

Δ2T for the Subarctic Winter model at 2° AOE and 90 mg/m2 (15 parts in 106 m) of GB.

Fig. 21
Fig. 21

Δ2T for the Subarctic Winter model at 4° AOE and 90 mg/m2 (15 parts in 106 m) of GB.

Fig. 22
Fig. 22

Figure 21 plus noise (1-s integration time).

Fig. 23
Fig. 23

Absorptivity of TCE.

Fig. 24
Fig. 24

Δ2T for 200 mg/m2 (37 parts at 106 m) of TCE at 1° AOE and the U.S. Standard Atmosphere plus noise (1-s integration time).

Fig. 25
Fig. 25

Absorptivity of MIC.

Fig. 26
Fig. 26

Δ2T for 500 mg/m2 (210 parts at 106 m) of MIC with the Tropical model at 1° AOE plus noise (1-s integration time).

Fig. 27
Fig. 27

Δ2T for 50 mg/m2 (21 parts in 106 m) of MIC with the Tropical model at 4° AOE plus noise (60-s integration time).

Fig. 28
Fig. 28

Absorptivity of HD.

Fig. 29
Fig. 29

Δ2T spectra for 90 mg/m2 (14 parts in 106 m) of HD at 1° AOE in the U.S. Standard model plus noise (60-s integration time).

Fig. 30
Fig. 30

Absorptivity of MCl.

Fig. 31
Fig. 31

Δ2T for 200 mg/m2 (96 parts in 106 m) of MCl in the U.S. Standard model at 1° AOE plus noise (60-s integration time).

Fig. 32
Fig. 32

Absorptivity of SO2.

Fig. 33
Fig. 33

Δ2T for 200 mg/m2 (75 parts in 106 m) of SO2, U.S. Standard model, at 1° AOE with noise (60-s integration time).

Tables (4)

Tables Icon

Table 1 Sensor Parameters

Tables Icon

Table 2 NESR and Mean NEΔT for the Sensor Described in Table 1 Operating in the U.S. Standard Atmosphere

Tables Icon

Table 3 Standard Atmospheric Models in modtran and lowtran

Tables Icon

Table 4 Target Compounds

Equations (21)

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

L i = ɛ i L i b b + τ i L i - 1 + ρ i ,
L i = ( 1 - τ T τ I τ A ) L i b b + τ T τ I τ A L i - 1 .
L 1 = L b g .
L 2 = τ T 2 τ A 2 L 1 + ( 1 - τ T A τ A 2 ) L 2 b b .
L 3 = τ A 3 L 2 + ( 1 - τ A 3 ) L 3 b b .
L 3 = τ A 3 [ τ A 2 τ T 2 L b g + ( 1 - τ A 2 τ T 2 ) L 2 b b ] + ( 1 - τ A 3 ) L 3 b b .
L 3 = τ A 3 [ τ A 2 τ T 2 L b g + ( 1 - τ A 2 τ T 2 ) L b l b b ] + ( 1 - τ A 3 ) L b l b b .
L 3 = L b l b b + τ A 2 τ T 2 τ A 3 ( L b g - L b l b b ) .
Δ L = ( L 3 - L b l b b ) = τ T 2 τ A ( L b g - L b l b b ) .
L = ɛ h c 2 ν ¯ 3 exp [ ( h c ν ¯ / k T ) ] - 1 = ɛ c 1 ν ¯ 3 exp [ ( c 2 ν ¯ / T ) ] - 1 ,
T b g = c 2 ν ¯ ln ( c 1 ν ¯ 3 L 3 + 1 ) .
Δ T = T b g - T b l = c 2 ν ¯ ln ( c 1 ν ¯ 3 L 3 + 1 ) - T b l .
Δ 2 T t = Δ ( Δ T ) = Δ T t - Δ T
Δ 2 L t = Δ ( Δ L ) = Δ L t - Δ L ,
SNR = P s NEP = τ s J Δ 2 L Δ ν ¯ NEP ,
NESR = NEP τ s J Δ ν ¯ .
s = A D Δ f D * ,
Δ f = 1 T s ,
NESR = A D / T s D * J τ s Δ ν ¯ .
Δ 2 L N = Δ 2 L + NESR .
NE Δ T = c 2 ν ¯ ln ( c 1 ν ¯ 3 d ν ¯ NESR + L b b b l + 1 ) - T b l .

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