Radio Science

A method for predicting the F1 layer critical frequency based on the Zurich smoothed sunspot number

Authors

  • E. D. DuCharme,

  • L. E. Petrie,

  • R. Eyfrig


Abstract

A series of expressions to calculate the monthly median F1 layer penetration frequency (ƒoF1) as a function of the ionospheric index IF2 was reported by DuCharme et al., [1971]. Using similar techniques and the same data base, development of a series of expressions to calculate ƒoF1 as a function of the Zurich smoothed sunspot number R12 is described. The derived expressions are evaluated for the period of maximum solar activity 1967 through 1969 and compared with observed ƒoF1 data for this period, which are outside the 1954 through 1966 data base used to develop the expressions.

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