Abstract

Stellar scintillation data were obtained on a single night at a variety of zenith distances and azimuths, using a photon-counting photometer recording at 100 Hz simultaneously at wavelengths of 0.475 μm and 0.870 μm. Orientable apertures of 42-cm diam separated by 1 m were used to establish the average upper atmosphere wind direction and velocity. Dispersion in the earth’s atmosphere separate the average optical paths at the two wavelengths, permitting a reconstruction of the spatial cross-correlation function for scintillations, independent of assumptions about differential fluid motions. Although there is clear evidence of a complicated velocity field, scintillation power was predominantly produced by levels at pressures of 130 ± 30 mbar. The data are not grossly inconsistent with layers of isotropic Kolmogorov turbulence, but there is some evidence for deviation from the Kolmogorov spectral index and/or anisotropy.

© 1981 Optical Society of America

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References

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  1. V. I. Tatarski, Wave Propagation in a Turbulent Medium (Dover, New York, 1967), p. 169.
  2. V. I. Tatarski, The Effects of the Turbulent Atmosphere on Wave Propagation (Israel Program of Scientific Translations, Jerusalem, 1971), p. 235.
  3. A. T. Young, Appl. Opt. 8, 869 (1969).
    [CrossRef] [PubMed]
  4. J. L. Bufton, Appl. Opt. 12, 1785 (1973).
    [CrossRef] [PubMed]
  5. A. Rocca, F. Roddier, J. Vernin, J. Opt. Soc. Am. 64, 1000 (1974).
    [CrossRef]
  6. G. D. Garland, Introduction to Geophysics (W. B. Saunders, Philadelphia, 1971), p. 39.
  7. W. B. Hubbard, J. R. Jokipii, B. A. Wilking, Icarus 34, 374 (1978).
    [CrossRef]
  8. J. T. Houghton, The Physics of Atmospheres (Cambridge U. P., London, 1977), p. 164.
  9. L. C. Lee, J. R. Jokipii, Astrophys. J. 202, 439 (1975).
    [CrossRef]

1978 (1)

W. B. Hubbard, J. R. Jokipii, B. A. Wilking, Icarus 34, 374 (1978).
[CrossRef]

1975 (1)

L. C. Lee, J. R. Jokipii, Astrophys. J. 202, 439 (1975).
[CrossRef]

1974 (1)

1973 (1)

1969 (1)

Bufton, J. L.

Garland, G. D.

G. D. Garland, Introduction to Geophysics (W. B. Saunders, Philadelphia, 1971), p. 39.

Houghton, J. T.

J. T. Houghton, The Physics of Atmospheres (Cambridge U. P., London, 1977), p. 164.

Hubbard, W. B.

W. B. Hubbard, J. R. Jokipii, B. A. Wilking, Icarus 34, 374 (1978).
[CrossRef]

Jokipii, J. R.

W. B. Hubbard, J. R. Jokipii, B. A. Wilking, Icarus 34, 374 (1978).
[CrossRef]

L. C. Lee, J. R. Jokipii, Astrophys. J. 202, 439 (1975).
[CrossRef]

Lee, L. C.

L. C. Lee, J. R. Jokipii, Astrophys. J. 202, 439 (1975).
[CrossRef]

Rocca, A.

Roddier, F.

Tatarski, V. I.

V. I. Tatarski, Wave Propagation in a Turbulent Medium (Dover, New York, 1967), p. 169.

V. I. Tatarski, The Effects of the Turbulent Atmosphere on Wave Propagation (Israel Program of Scientific Translations, Jerusalem, 1971), p. 235.

Vernin, J.

Wilking, B. A.

W. B. Hubbard, J. R. Jokipii, B. A. Wilking, Icarus 34, 374 (1978).
[CrossRef]

Young, A. T.

Appl. Opt. (2)

Astrophys. J. (1)

L. C. Lee, J. R. Jokipii, Astrophys. J. 202, 439 (1975).
[CrossRef]

Icarus (1)

W. B. Hubbard, J. R. Jokipii, B. A. Wilking, Icarus 34, 374 (1978).
[CrossRef]

J. Opt. Soc. Am. (1)

Other (4)

G. D. Garland, Introduction to Geophysics (W. B. Saunders, Philadelphia, 1971), p. 39.

J. T. Houghton, The Physics of Atmospheres (Cambridge U. P., London, 1977), p. 164.

V. I. Tatarski, Wave Propagation in a Turbulent Medium (Dover, New York, 1967), p. 169.

V. I. Tatarski, The Effects of the Turbulent Atmosphere on Wave Propagation (Israel Program of Scientific Translations, Jerusalem, 1971), p. 235.

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Figures (9)

Fig. 1
Fig. 1

Geometry for average ray paths in a dispersive atmosphere.

Fig. 2
Fig. 2

Schematic contour plot of the two-aperture spatial correlation function for arbitrary aperture orientation. Solid vectors represent various traversals of the self-correlation function in unit time interval due to different wind velocities. Dashed vectors are the same but for the cross-correlation function.

Fig. 3
Fig. 3

Blue self-correlation C1 (solid curve), red self-correlation C2 (dashed curve), and cross-correlation C12 (dot–dash curve) for Z = 71.8°, θ = 235.6°. Inset shows the orientation of the assumed wind vector and dual-aperture correlation function with respect to the projected vertical and horizontal.

Fig. 4
Fig. 4

Same as Fig. 3 but for Z = 73.9°, θ = 237.5°.

Fig. 5
Fig. 5

Same as Fig. 3 but for Z = 75.0°, θ = 238.6°.

Fig. 6
Fig. 6

Same as Fig. 3 but for Z = 76.0°, θ = 239.4°. Projected assumed wind appears to rise vertically from the horizon.

Fig. 7
Fig. 7

Same as Fig. 3 but for Z = 70.9°, θ = 152.6°. The projected assumed wind moves parallel to the horizon, but we see from C12 that the actual projected average wind is inclined by ~5° to the horizon.

Fig. 8
Fig. 8

Same as Fig. 3 but for Z = 70.3°, θ = 153.8°. Thinner curve shows C1, C2, C12 (all are identical) at the zenith.

Fig. 9
Fig. 9

Theoretical profile of the spatial cross-correlation function for two apertures along the line of centers (heavier curves) and perpendicular to the line of centers (lighter dot–dash curves).

Tables (1)

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Table I Upper Atmosphere Parameters on 16 Aug. from Radiosonde Data

Equations (13)

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d θ = p d r r ( n 2 r 2 - p 2 ) 1 / 2 ,
p = n r sin i ,
n = 1 + c ρ ,
θ R - θ B = - ( c R - c B ) tan Z sec 2 Z a r ( ρ / r ) d r ,
ϕ 1 i = ( I 1 i - I 1 a v ) / σ 1 ,
C 1 ( τ ) = 1 N j i ϕ 1 i ϕ 1 ( i + j ) ,
C 12 ( τ ) = 1 N j i ϕ 1 i ϕ 2 ( i + j ) .
C th ( two apertures ) = C s th ( r ) + ½ C s th ( r + d ) + ½ C s th ( r - d ) C s th ( 0 ) + C s th ( d ) ,
Δ y = 3.973 cm ( P a - P r ) tan Z sec Z ,
λ F = [ λ ( r - a ) / cos Z ] 1 / 2 ,
d r C ( r ) = 0 ,
0 r d r C ( r ) = 0 ,
0 d y C ( y ) = 0 .

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