Letter | Published:

Semi-annual Variation in Density at a Height of 90 km

Nature volume 222, pages 969971 (07 June 1969) | Download Citation

Subjects

Abstract

A SEMI-ANNUAL variation in upper-atmosphere density, with maxima in April and October and minima in January and July, was first detected in 1961 by Paetzold and Zschörner1 from the analysis of satellite orbits at heights of 210–650 km. By 1965 it seemed that the main features of the semi-annual variation had been established. Using observational values of density obtained at heights between 350 and 750 km, Jacchia2 found that the variation with height of the semi-annual effect was similar to that shown by other types of upper-atmosphere variation. He therefore suggested that the effect could be represented by assuming temperature variations in the thermosphere, the magnitude of the temperature variations being proportional to the average 10.7 cm solar radiation flux, which is often used as the best available index for solar extreme ultraviolet radiation.

Access optionsAccess options

Rent or Buy article

Get time limited or full article access on ReadCube.

from$8.99

All prices are NET prices.

References

  1. 1.

    , , Space Res., 2, 958 (North-Holland, Amsterdam, 1961).

  2. 2.

    , Ann. Géophys., 22, 75 (1966).

  3. 3.

    , and , Plan. Space Sci., 14, 1149 (1966).

  4. 4.

    , Plan. Spa. Sci., 15, 627 (1967).

  5. 5.

    , and , Plan. Space Sci., 16, 675 (1968).

  6. 6.

    , and , Nature, 222, 153 (1969).

  7. 7.

    US Standard Atmosphere Supplements, 1966 (US Gov. Printing Office, Washington, 1967).

  8. 8.

    , Ann. Gsophys. (in the press).

Download references

Author information

Affiliations

  1. Royal Aircraft Establishment, Farnborough, Hampshire.

    • G. E. COOK

Authors

  1. Search for G. E. COOK in:

About this article

Publication history

Received

Published

DOI

https://doi.org/10.1038/222969a0

Further reading

Comments

By submitting a comment you agree to abide by our Terms and Community Guidelines. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate.