The global/seasonal/local-time distributions of scintillation occurrence rate have been obtained from the in-situ density measurement of ROCSAT-1 during moderate to high solar activity periods of 2000 to 2003. The scintillation was obtained with a modified procedure of the thin-phase screen model of Rino reported in Wernik et al. [2007]. The distribution of the S4 index for the weak scintillation (S4<0.3) is almost identical to that of the equatorial irregularity distribution reported in the literature. However, as the scintillation level increases (0.3< S4<0.6), the latitudinal distribution moves to the equatorial ionization anomaly (EIA) region. In addition, the distributions of the outer scale values that are valuable for the study of physical evolution of the irregularity structure are also obtained. The occurrence distribution of scintillation activity with several parameters such as dip-latitude, longitude, local time, solar activity, and geomagnetic activity during different seasons are presented and discussed in the report. In addition, a special case of coincident observation that occurred on 24 March 2000 between the irregularity structure measured by ROCSAT-1 and the scintillation experiment at the Ascension Island has been studied. The study of scintillation statistics is carried out first and the results shows that the Nakagami distribution can portray the scintillation intensities with S4 up to 1.4 for the L-band scintillation. Moreover, the departure of frequency dependence of S4 predicted by the weak scintillation is noticed due to the multiple scattering effect. The measurements between the satellite and scintillation data are then compared against each other to study the similarity in the gross feature between the characteristics of irregularity structure and the scintillation variation. The causal relationship between the fluctuation of ion density and the scintillation variation is obtained. The coincident observations are also validated by the PEM simulation result.
