MORPHOLOGIES OF GLOBAL IONOSPHERIC DISTURBANCES DURING DIFFERENT TYPE GEOMAGNETIC DISTURBANCE EVENTS
不同地磁扰动事件期间全球电离层的扰动形态分析

Using the observation data from the global ionospheric stations, we analyze the disturbance morphologies of global ionospheric F 2-layer (f 0F 2 and h mF 2) during five different type geomagnetic disturbance events. The main results show that: for magnetic storms with delayed main phase, types S(C) and S(E), the middle-high latitude ionosphere appears the evident positive phase disturbance first and the following negative phase disturbance is evidently delayed; the negative phase disturbance covers a wide region, even extends into the low-latitude, lasts a longer time, and recovers very slowly, in which the disturbance of types S(C) is more evident . For magnetic storm with no-delayed main phase, types S(A), S(B) and S(D), the ionospheric positive phase disturbance at the high-latitude lasts a shorter time, even does not appear at all, and the following middle-high latitude ionospheric negative phase disturbance starts, develops, and recovers rapidly. The intensity of magnetic storm main phase has certain effect on the intensity, development and periods of ionospheric negative phase disturbance. The ionospheric disturbances at the high-latitude have the evident local time effect in the recovery phase of storm with no delayed main phase. The local time effect is enhanced with the reduction of latitude, and evidently affects on the ionosphere disturbances at the middle-low latitudes. Generally, there are great differences for the ionospheric disturbances at different latitude regions, which reflect the interactions of the different physical processes.