Abstract

The attenuation coefficient ratio (αλ/α0.546) for artificial fogs has been measured at 345 μ. The attenuation coefficient ratios at 0.436 μ, 1.01 μ, 3.5 μ, 10 μ, and 13.5 μ were also measured so that a comparison between artificial fogs and natural fogs could be made. By comparing our results with others on natural fogs and with the theoretical work of others in the visible and near ir, we have concluded that our artificial fogs closely resemble natural fogs. We conclude, therefore, that α345/α0.546 is representative of real fogs. Artificial fogs are generated and allowed to dissipate during which time attenuation of light at several wavelengths is recorded. The green line of the mercury arc at 0.546 μ was used as the standard of comparison. For radiation at 345 μ, α345/α0.546 = 0.014 ± 0.009 during the generation time of the fog and 0.021 ± 0.006 during the time the fog is allowed to dissipate.

© 1967 Optical Society of America

Full Article  |  PDF Article

References

  • View by:
  • |
  • |
  • |

  1. A. Arnulf, J. Bricard, E. Curé, C. Véret, J. Opt. Soc. Am. 47, 491 (1957).
    [CrossRef]
  2. V. Ye. Zuyev, B. P. Koshelev, S. D. Tvorogov, S. S. Khmelevtsov, Fiz. Atm. Okeana 1, 509 (1965).
  3. D. Deirmendjian, Appl. Opt. 3, 187 (1964).
    [CrossRef]
  4. W. J. Burroughs, E. C. Pyatt, H. A. Gebbie, Nature 212, 387 (1966).
    [CrossRef]
  5. E. Reisman, C. Bartky, G. D. Cumming (Appl. Opt. 6,November (1967).
    [CrossRef] [PubMed]

1967 (1)

E. Reisman, C. Bartky, G. D. Cumming (Appl. Opt. 6,November (1967).
[CrossRef] [PubMed]

1966 (1)

W. J. Burroughs, E. C. Pyatt, H. A. Gebbie, Nature 212, 387 (1966).
[CrossRef]

1965 (1)

V. Ye. Zuyev, B. P. Koshelev, S. D. Tvorogov, S. S. Khmelevtsov, Fiz. Atm. Okeana 1, 509 (1965).

1964 (1)

1957 (1)

Arnulf, A.

Bartky, C.

E. Reisman, C. Bartky, G. D. Cumming (Appl. Opt. 6,November (1967).
[CrossRef] [PubMed]

Bricard, J.

Burroughs, W. J.

W. J. Burroughs, E. C. Pyatt, H. A. Gebbie, Nature 212, 387 (1966).
[CrossRef]

Cumming, G. D.

E. Reisman, C. Bartky, G. D. Cumming (Appl. Opt. 6,November (1967).
[CrossRef] [PubMed]

Curé, E.

Deirmendjian, D.

Gebbie, H. A.

W. J. Burroughs, E. C. Pyatt, H. A. Gebbie, Nature 212, 387 (1966).
[CrossRef]

Khmelevtsov, S. S.

V. Ye. Zuyev, B. P. Koshelev, S. D. Tvorogov, S. S. Khmelevtsov, Fiz. Atm. Okeana 1, 509 (1965).

Koshelev, B. P.

V. Ye. Zuyev, B. P. Koshelev, S. D. Tvorogov, S. S. Khmelevtsov, Fiz. Atm. Okeana 1, 509 (1965).

Pyatt, E. C.

W. J. Burroughs, E. C. Pyatt, H. A. Gebbie, Nature 212, 387 (1966).
[CrossRef]

Reisman, E.

E. Reisman, C. Bartky, G. D. Cumming (Appl. Opt. 6,November (1967).
[CrossRef] [PubMed]

Tvorogov, S. D.

V. Ye. Zuyev, B. P. Koshelev, S. D. Tvorogov, S. S. Khmelevtsov, Fiz. Atm. Okeana 1, 509 (1965).

Véret, C.

Zuyev, V. Ye.

V. Ye. Zuyev, B. P. Koshelev, S. D. Tvorogov, S. S. Khmelevtsov, Fiz. Atm. Okeana 1, 509 (1965).

Appl. Opt. (2)

D. Deirmendjian, Appl. Opt. 3, 187 (1964).
[CrossRef]

E. Reisman, C. Bartky, G. D. Cumming (Appl. Opt. 6,November (1967).
[CrossRef] [PubMed]

Fiz. Atm. Okeana (1)

V. Ye. Zuyev, B. P. Koshelev, S. D. Tvorogov, S. S. Khmelevtsov, Fiz. Atm. Okeana 1, 509 (1965).

J. Opt. Soc. Am. (1)

Nature (1)

W. J. Burroughs, E. C. Pyatt, H. A. Gebbie, Nature 212, 387 (1966).
[CrossRef]

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.


Figures (5)

Fig. 1
Fig. 1

Schematic diagram of the optical system. The three broken lines after mirror A represent three separate wavelengths. The first is monitored by the photomultiplier tube PM with an S–20 surface, the second by the photomultiplier tube PM with an S–1 surface. The third is reflected by the mirror B which may be adjusted to change the ir wavelength to be detected by the thermocouple TC. Radiation to the interferometer is detected by a helium-cooled gallium-doped germanium detector. The mirror C is normally the traveling mirror of the interferometer, but is set at the same distance as D from the Mylar beam splitter. The fog chamber is 2.48 m long.

Fig. 2
Fig. 2

Relative spectral intensity vs wavelength for the far ir.

Fig. 3
Fig. 3

Recorder trace of a typical fog generation–dissipation cycle for 0.546-μ, 1.01-μ, and 10-μ radiation. An optical shutter placed in the beam in the middle of each cycle determines zero transmittance as indicated between the vertical dashed lines. G represents changes in gain. The 100% line is for the gain setting at the beginning and end of the cycle only. The liquid nitrogen is turned on at time T = 0 and off at the time indicated at the end of the generation (GEN) portion of the cycle.

Fig. 4
Fig. 4

Ratio of attentuation coefficients αλ/α0.546 plotted against α0.546 for three wavelengths. ○’s and ×’s represent fog generation and fog dissipation, respectively.

Fig. 5
Fig. 5

Ratio of attenuation coefficients αλ/α0.546 plotted against wavelength. ○’s and ×’s represent fog generation and fog dissipation, respectively. Two values for fog dissipation at 0.436 μ indicate that there are two drop size distributions as seen by this wavelength. The △’s represent Diermendjian’s theoretical calculations and are αλ/α0.45. The solid lines are theoretical curves of Zuyev et al.2 for a drop size distribution given by f(a) = 1/[Γ(μ + 1)]−1τ μ +1 (τ μ /r)e μτ , where τ = a/r, a is the radius of the drops, r is the most probable radius in the distribution, and μ is a parameter characterizing the distribution half-width. For curve A, μ = 2, r = 3; curve B, μ = 2, r = 2; curve C, μ = 10, r = 3; curve D, μ = 10, r = 2.

Tables (2)

Tables Icon

Table I Bandpasses, Sources, and Detectors

Tables Icon

Table II Ratio of Attenuation Coefficients αλ/α0.546

Metrics