Relationship between strong range spreadFand ionospheric scintillations observed in Hainan from 2003 to 2007

Abstract

Data from a DPS-4 Digisonde and an ionospheric scintillation monitor, both located at the low-latitude station Hainan (109.1 degrees E, 19.5 degrees N; dip latitude 9 degrees N), were analyzed to study the strong range spread F (SSF) and its correlation with ionospheric scintillations observed in the period of declining solar cycle 23 from 2003 to 2007. The results show that the maximum and minimum of the occurrence of SSF appeared in nearly the same months as those of the GPS L band scintillations. The variations in SSF occurrence were also similar to those of the scintillations. From 2003 to 2007, both the SSF and the scintillation occurrences decreased from the high solar activity year to the low solar activity year. The correlation coefficient between the occurrences of the SSF and the GPS L band scintillation was as high as 0.93, suggesting associated mechanisms producing SSF and scintillations. Electron density depletions extending from the bottomside to the topside ionosphere are the likely cause explaining the high correlation.