Letter | Published:

Daytime Seeing and Thermal Structure in the Lower Atmosphere

Nature volume 212, pages 5859 (01 October 1966) | Download Citation



SOLAR observing is severely hampered by the turbulent fluctuations of temperature and, therefore, refractive index in the lower atmosphere. Under certain conditions, however, ascending warm convection plumes are interspersed with sinking environmental air which is remarkably devoid of temperature fluctuations1–4. It is presumably this air which affords the brief intervals of excellent seeing which are sometimes encountered5,6. The suggested conditions under which these intervals should occur7 are that the optical path should lie above the Obukhov height L (which has a strong dependence on the wind strength) and should slope roughly parallel with the plumes. That is to say, it should slant upwards in the wind direction at an inclination of about 40°–60° to the horizontal.

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  1. 1.

    , Austral. J. Phys., 11, 168 (1958).

  2. 2.

    , Turbulent Transfer in the Lower Atmosphere (Univ. of Chicago Press, Chicago, 1959).

  3. 3.

    , and , J. App. Meteorol., 2, 180 (1963).

  4. 4.

    , and , J. Atmos. Sci., 20, 313 (1963).

  5. 5.

    , and , Austral. J. Phys., 14, 14 (1961).

  6. 6.

    , and , Z. Astrophys., 63, 101 (1966).

  7. 7.

    , App. Opt., 3, 1329 (1964).

  8. 8.

    , Quart. J. Roy. Meteorol. Soc., 90, 119 (1964).

  9. 9.

    , J. Opt. Soc. Amer., 55, 806 (1965).

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Author information


  1. C.S.I.R.O. Division of Meteorological Physics, Aspendale, Victoria.

    • E. K. WEBB
  2. C.S.I.R.O. Division of Physics, National Standards Laboratory, Sydney, Australia.

    • C. E. COULMAN


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