Amplitude scintillation index derived from C/N_0 measurements released by common geodetic GNSS receivers operating at 1 Hz

摘要

Two widely used scintillation indexes S4 and s. are generated by dedicated ionospheric scintillation monitoring receivers (ISMRs), which typically have 50-Hz temporal resolution and thus require substantial memory capabilities. Taking into consideration the huge number of common Global Navigation Satellite System (GNSS) receivers, the derivation of a GNSS receiver-based scintillation index as a supplement to the ISMR indexes is expected to improve the study of ionospheric scintillation. We developed an amplitude scintillation index, S4c, which is derived from the carrier-to-noise density ratio (C/N0) data released by common geodetic GNSS receivers operating at 1-Hz. The reliability of the S4c index is compared with the typical scintillation index S4 of three ISMRs located in Hong Kong and Brazil. The statistics indicate that during scintillation activity, the correlation coefficient between S4c (derived from common receivers) and S4 (generated by ISMRs) is generally higher than 0.9. The reliability of S4c was also verified based on 1-year observations from two adjacent stations in Hong Kong, which are equipped with Leica GR50 and Septentrio PolaRxS Pro receivers, respectively. Long-term scintillation occurrence (S4c > 0.2 vs. S4 > 0.2) rates show good agreement between S4c and S4. In addition, two-dimensional S4c maps (1 degrees x1 degrees) generated by GPS L1 and BDS B1 signals data collected at 117 continuous operation tracking stations in China clearly show post-sunset super plasma bubbles as the source of ionospheric scintillation during the main phase of the intense storm that occurred on September 8, 2017. These results demonstrate the feasibility of using the S4c index derived from the large volume of GNSS observations recorded by non-scintillation GNSS receivers for the study and monitoring of ionospheric scintillation.