SUDDEN IONOSPHERIC OSCILLATIONS ACCOMPANYED WITH SUDDEN COMMERCEMENT OF GEOMAGNETIC STORM OF MARCH 8-20,1989

Ionospheric disturbances were observed at wuhan Ionospheric Observatory duringthe period of March 1989 severe geomagnetic storms which attributed to a series of solarflares form the Active Region 5395. Among these ionospheric disturbances, there existedsome events of sudden ionospheric oscillations(SIOs) which occurred simultaneously with the corresponding sudden commencements(SC) of geomagnetic storms as being observed at Wuhan Geomagnetic Observatory.