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GEOGRAPHIC DISTRIBUTION OF IONOSPHERIC DISTURBANCE IN THE F2 LAYER,
DIRECTORATE OF SCIENTIFIC INFORMATION SERVICES OTTAWA (ONTARIO)
An analysis was made of ionospheric disturbance synoptic charts and of longitudinal distribution graphs of the percentage departures of the critical frequency. It was concluded that For a day or two before the commencement of a magnetic storm the departure curves in the mean lie above the zero level. At the commencement of a magnetic storm the negative departures increase, reaching 80, with the maximum negative departures mainly associated with longitudes 180 deg W - 70 deg E. During an active storm period the negative departures extend to all longitudes, and are as much as 60-80. The maximum negative departures are at longitudes 180 deg W - 70 deg E. During this period total absorption is observed at longitudes 80-140 deg W. Such distribution, it seems, may be explained by dependence of delta f sub oF2 on geomagnetic latitude. At the end of a magnetic storm the curves are observed to rise toward zero level. Consideration was given to how these conclusions could possibly be applied in the practical work of short-term forecasting of radio conditions.
Trans. of Akademiya Nauk SSSR. Institut Zemnogo Magnetizma Ionosfery Rasprostraneniya Radiovoln. Trudy, 1961, no. 19(29) p. 31-43. Also available from NRC as C-4393.