Mapping of S4 Over the Arabian Peninsula During Solar Minimum

In this letter, we study the temporal and spatial variability of ionospheric irregularities by generating high-resolution maps of the observed amplitude scintillation index (S4) using data from a multi-constellation and multi-frequency GNSS receiver. The study region is the Arabian Peninsula, which falls under the northern crest of the equatorial ionization anomaly (EIA). Even though the study was conducted during a solar minimum period, considerable occurrences of pre-sunset scintillation have been observed between 15-17 local time, particularly during the winter solstices. While most scintillation occurrences have been observed at low elevation (15 to 30 degrees), a considerable number of scintillation patches have been observed towards the north, east, and southeast of the receiver location, for elevation angles ranging from 40 to 60 degrees. Our analysis shows that BeiDou geostationary orbit (GEO) and inclined GEO (IGSO) satellites may have been the main contributor to the increased number of scintillation occurrences observed around the eastern side of the receiver as compared to the western side. Out of all the GNSS constellations with MEO satellites, GPS was the most impacted by amplitude scintillation, while BeiDou and Galileo satellites were the least affected. It is anticipated that the patches of ionospheric irregularities reported in this work would be further enhanced as the solar activity increases in the coming years. Therefore, this work can serve as a reference for future studies during periods of increased geomagnetic activity.

Mapping of S4 Over the Arabian Peninsula During Solar Minimum

In this letter, we study the temporal and spatial variability of ionospheric irregularities by generating high-resolution maps of the observed amplitude scintillation index (S4) using data from a multi-constellation and multi-frequency GNSS receiver. The study region is the Arabian Peninsula, which falls under the northern crest of the equatorial ionization anomaly (EIA). Even though the study was conducted during a solar minimum period, considerable occurrences of pre-sunset scintillation have been observed between 15-17 local time, particularly during the winter solstices. While most scintillation occurrences have been observed at low elevation (15 to 30 degrees), a considerable number of scintillation patches have been observed towards the north, east, and southeast of the receiver location, for elevation angles ranging from 40 to 60 degrees. Our analysis shows that BeiDou geostationary orbit (GEO) and inclined GEO (IGSO) satellites may have been the main contributor to the increased number of scintillation occurrences observed around the eastern side of the receiver as compared to the western side. Out of all the GNSS constellations with MEO satellites, GPS was the most impacted by amplitude scintillation, while BeiDou and Galileo satellites were the least affected. It is anticipated that the patches of ionospheric irregularities reported in this work would be further enhanced as the solar activity increases in the coming years. Therefore, this work can serve as a reference for future studies during periods of increased geomagnetic activity.

Mapping of S4 Over the Arabian Peninsula During Solar Minimum

In this letter, we study the temporal and spatial variability of ionospheric irregularities by generating high-resolution maps of the observed amplitude scintillation index (S4) using data from a multi-constellation and multi-frequency GNSS receiver. The study region is the Arabian Peninsula, which falls under the northern crest of the equatorial ionization anomaly (EIA). Even though the study was conducted during a solar minimum period, considerable occurrences of pre-sunset scintillation have been observed between 15-17 local time, particularly during the winter solstices. While most scintillation occurrences have been observed at low elevation (15 to 30 degrees), a considerable number of scintillation patches have been observed towards the north, east, and southeast of the receiver location, for elevation angles ranging from 40 to 60 degrees. Our analysis shows that BeiDou geostationary orbit (GEO) and inclined GEO (IGSO) satellites may have been the main contributor to the increased number of scintillation occurrences observed around the eastern side of the receiver as compared to the western side. Out of all the GNSS constellations with MEO satellites, GPS was the most impacted by amplitude scintillation, while BeiDou and Galileo satellites were the least affected. It is anticipated that the patches of ionospheric irregularities reported in this work would be further enhanced as the solar activity increases in the coming years. Therefore, this work can serve as a reference for future studies during periods of increased geomagnetic activity.

Evaluation of Concurrent Variation in Rain Specific Attenuation and Tropospheric Amplitude Scintillation Over Akure, Southwest Nigeria

Rain constitutes a major limitation to the performance and use of terrestrial and satellite communication systems with operational frequencies greater than 10 GHz. The situation gets further complicated by fast fluctuations in the received signal amplitude due to in homogeneities in atmospheric weather conditions; a phenomenon known as amplitude scintillation. The concurrent evaluation of the two phenomena guarantees a better fade margin determination for the planning of radio communication over any location. This work employs 3 years of in-situ measurement of temperature, humidity, rainfall rate and rainfall amount for the estimation of tropospheric amplitude scintillation and rain specific attenuation over Akure (7.17° N, 5.18° E, 358 m) South West Nigeria. Davis vantage pro weather station at 1-min integration time was used for the measurement and the ITU models for rain specific attenuation (ITU-R P.838-3) and amplitude scintillation (ITU–R 618-13) were employed for the estimation. Time series and statistical analyses of the phenomena show that rain attenuation is the more prominent cause of signal degradation at Ku-band frequencies. Nevertheless, the need to make an extra fade margin allowance of about 0.25 dB due to amplitude scintillation fade subsists to forestall any loss of synchronization on the link. Also, a 3-parameter power-law expression developed for estimating amplitude scintillation fade from rain attenuation performed excellently well, as indicated by average root mean square error (RMSE) and coefficient of determination (R2) values of 0.002151 and 0.8747, respectively.

Instantaneous Ionospheric Scintillation Mapping over the East African Region by use of GPS Derived Amplitude Scintillation Proxy

Ionospheric scintillation activity over the East African region is often monitored using measurements from the SCIntillation Network Decision Aid (SCINDA) receivers. Many of the SCINDA receivers over East Africa are currently not archiving data and therefore a large part of the region remain un sampled. We investigated the possibility to use dual frequency receivers of the Global Navigation Satellite System (GNSS) network for scintillation mapping. A proxy for amplitude scintillation was first derived by scaling the rate of change of total electron content index (ROTI). The proxy was validated against S4 derived from nearly collocated SCINDA receivers over the region. A good correlation was observed between the proxy and S4. The proxy was then used to map the occurrence of amplitude scintillation over East Africa based on semivariogram modeling and Kriging interpolation technique. The results indicate that the S4 values had a good positive correlation with *Corresponding author: E-mail: [email protected]; Amabayo et al.; AJR2P, 4(2): 6-20, 2021; Article no.AJR2P.66815 the simulated S4p from the Kriging interpolation. This observation suggests that data from the dual frequency receivers of GNSS may be used to map scintillation over East Africa. These maps can in turn be used to study the evolution of ionospheric scintillation patterns over the region.

Climatology of Ionospheric Amplitude Scintillation on GNSS Signals at South American Sector During Solar Cycle 24

Scintillations are caused by ionospheric irregularities and can affect the propagation of trans-ionospheric radio signals. One way to understand and predict the impact of such irregularities on Global Navigation Satellite System (GNSS) signals is through the climatological behavior of the ionospheric scintillation indexes during the different phases of a solar cycle. In this work, we investigate the amplitude scintillation index S4 during the full solar cycle 24 at South American (SA) sector, that is featured by the Ionospheric Anomaly (EIA) and by the South Atlantic Magnetic Anomaly (SAMA). We also investigate the daily variation of S4 and two case studies during geomagnetic storms. The results show a significant intensification of amplitude scintillations at northern and southern crest of EIA, especially during the southern hemisphere’s spring/summer seasons, with a higher increase during solar maximum, and after sunset. And particularly at the SAMA region, where the intensity of magnetic field lines is lower, the S4 fluctuations are much higher.