Ionospheric variability: a comparative statistical study

Studying the variabilities from day-to-day and from hour-to-hour of the ionospheric characteristics f 0E, f 0F2, M(3000)F2 and MUF(3000)F2 we have determined statistical factors related to the state of the ionospheric plasma in time and space. It is found that the variability from day-to-day is greater than the variability from hour-to-hour and that an “intrinsic” variability of the order of less than 4% remains even if we evaluate variability levels that are not exceeded for the 30% or 20% or 10% of the time for each month and year at each location. It is also found that a different amount of disturbances exists at different geographical zones (continents) and at the same zone it varies with latitude.