Comparison on ionosphere spread-F between high and low latitude regions during the storm time

Contrastive study of Spread-F between different latitudes of ionosphere is an important method to investigate ionospheric disturbance propagation. In this paper, data from three DPS-4 digisondes located at low and high latitude regions were used to study the ionospheric Spread-F properties during the six storm times. The results show that, the observed types of Spread-F over high and low latitudes are not exactly the same. And the start time of Spread-F will be later if the latitude of the station is lower. It implies that propagation of the ionospheric irregularities which caused the Spread-F is from high latitude to low latitude ionosphere.