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Radio Science

Seasonal and day-to-day variability of total electron content at mid-latitudes near solar maximum


  • H. Soicher,

  • F. J. Gorman


Faraday rotation observations were conducted at Fort Monmouth, New Jersey (40.15°N, 74.01°W), utilizing beacon transmissions from a geostationary satellite during the period just following the maximum phase of solar cycle 21. Seasonal and day-to-day variabilities are observed. Unique representation of the data has permitted the study of the day-to-day variability of derived total electron content (TEC) values. For example, winter data indicate uniformity of day-to-day TEC values during the buildup and decay phases of the diurnal variation, and summer data indicate uniformity during the predawn and sunrise phases, whereas equinox data indicate wide variability during all phases. In addition, winter and summer data indicate that during non-magnetically-disturbed periods, TEC values at the diurnal peak, which exceed monthly mean values, tend to occur on consecutive days. During the equinoxes the peak values may occur randomly. The response of TEC to magnetic activity is also discussed. Since day-to-day variability is a most difficult quantity to predict, the results have implications for prediction improvement.

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