Morphological study of L-band ionospheric scintillations in the equatorial region

Using the observation data (Jul. 2003-Jun. 2005) from GPS scintillation monitor at CSSAR Hainan station, a morphological analysis for L-band ionospheric scintillations over Hainan region in the fall phase of solar cycle has been performed. The main results are the following. Scintillations mainly occur from postsunset to near midnight. The onset time of scintillations is clearly earliest with the peaks on near 22LT in equinox months, and has some time delay in winter months, and has an obviously time delay which mainly takes place near midnight in summer months. The occurrence rate and intensity of scintillations are evidently enhanced in equinox months, and are evidently reduced in winter and summer months. The scintillations mainly occur on the magnetic quiet days, which mainly take place near the two equinoxes. The scintillations may also occur in magnetic disturbance/ storm days, which mostly appear in winter and summer months. Compared with the geomagnetic activity, the solar activity does not evidently affect the scintillation occurrence.