Journal cover Journal topic
Annales Geophysicae An open-access journal of the European Geosciences Union
Ann. Geophys., 35, 1201-1218, 2017
https://doi.org/10.5194/angeo-35-1201-2017
© Author(s) 2017. This work is distributed under
the Creative Commons Attribution 3.0 License.
Regular paper
08 Nov 2017
Climatology and modeling of ionospheric scintillations and irregularity zonal drifts at the equatorial anomaly crest region
Marcio T. A. H. Muella1, Marcelo H. Duarte-Silva1, Alison O. Moraes2, Eurico R. de Paula3, Luiz F. C. de Rezende3, Lucilla Alfonsi4, and Bruno J. Affonso5 1Universidade do Vale do Paraíba-UNIVAP, Institute of Research and Development-IP&D, São José dos Campos, São Paulo, 12.244-000, Brazil
2Instituto de Aeronáutica e Espaço-IAE, São José dos Campos, São Paulo, 12.228-904, Brazil
3Instituto Nacional de Pesquisas Espaciais-INPE, São José dos Campos, São Paulo, 12.227-010, Brazil
4Istituto Nazionale di Geofisica e Vulcanologia-INGV, Rome, 00143, Italy
5Empresa Brasileira de Aeronáutica S.A.-Embraer, São José dos Campos, São Paulo, 12.227-901, Brazil
Abstract. In this study the climatology of ionospheric scintillations and the zonal drift velocities of scintillation-producing irregularities are depicted for a station located under the southern crest of the equatorial ionization anomaly. Then, the α − μ ionospheric fading model is used for the first- and second-order statistical characterization of amplitude scintillations. In the statistical analyzes, data are used from single-frequency GPS receivers acquired during ∼ 17 years (September 1997–November 2014) at Cachoeira Paulista (22.4° S; 45.0° W), Brazil. The results reveal that the nocturnal occurrence of scintillations follows the seasonal distribution of plasma bubble irregularities observed in the longitudinal sector of eastern South America. In addition to the solar cycle dependence, the results suggest that the occurrence climatology of scintillations is also modulated by the secular variation in the dip latitude of Cachoeira Paulista, since the maximum occurrence of scintillations during the peak of solar cycle 24 was ∼ 20 % lower than that observed during the maximum of solar cycle 23. The dynamics of the irregularities throughout a solar cycle, as investigated from the estimates of the mean zonal drift velocities, presented a good correlation with the EUV and F10.7 cm solar fluxes. Meanwhile, the seasonal behavior showed that the magnitude of the zonal drift velocities is larger during the December solstice months than during the equinoxes. In terms of modeling, the results for the α − μ distribution fit quite well with the experimental data and with the temporal characteristics of fading events independently of the solar activity level.

Citation: Muella, M. T. A. H., Duarte-Silva, M. H., Moraes, A. O., de Paula, E. R., de Rezende, L. F. C., Alfonsi, L., and Affonso, B. J.: Climatology and modeling of ionospheric scintillations and irregularity zonal drifts at the equatorial anomaly crest region, Ann. Geophys., 35, 1201-1218, https://doi.org/10.5194/angeo-35-1201-2017, 2017.
Publications Copernicus
Download
Short summary
In this study we analyzed ~ 17 years of GPS data from receivers installed in the observatory of Cachoeira Paulista, Brazil. We statistically analyzed the occurrence of GPS signal amplitude fluctuations caused by irregularities in the Earth's upper atmosphere. These signal fluctuations are known to provoke positional errors for GPS users. The results revealed that the secular variations in the Earth’s magnetic field are affecting the climatology of such GPS signal fluctuations.
In this study we analyzed ~ 17 years of GPS data from receivers installed in the observatory of...
Share