The total electron content (TEC), measured by means of navigation satellite systems such as GPS, GLONASS, GALILEO, has turned into a key parameter in the characterization and monitoring of ionosphere on a global scale. However, from the point of view of ionospheric radio propagation, the most important characteristic is the F2 layer critical frequency (foF2), whose value directly defines an optimum working frequency for near verical incidence skywave (NVIS) propagation. The ionospheric density profile and its maximum electron density (NmF2) is directly related to foF2 which is being regularly measured by ionosondes. The spatial coverage of foF2 ionosonde observations is not globally uniform due to the high cost of acquiring and maintain ionosphericing ionosondes. This limitation can be surpassed considering the abundance of GPS receiver networks that provide TEC observations which can be used jointly with ionospheric slab thickness models to improve the foF2 predictability and therefore to provide support for various HF communication systems, radio amateurs and broadcaster operators.
Houminer has investigated the use of GPS data in relation to short-term foF2 prediction enhancement using one ionosonde station located in Cyprus and concluded that the high correlation between TEC GPS with foF2 (varying from 0.53 to 0.78) allows the use of GPS data for near real time foF2 map updating, both in temporal (short-term, medium and long-term) and in spatial (local, regional and global) terms. Kouris concluded that there is a high correlation between the TEC and the square of foF2 (around 0.8), al- though ionospheric hysteresis is detected before and after noon time.
Author(s) Details:
Buldan Muslim
Geospatial Research Center of National Research and Innovation Agency (BRIN), Indonesia.
Mukhamad Nur Cahyadi
Sepuluh Nopember Institute of Technology, Surabaya, Indonesia.
Haris Haralambous
Frederick University, Cyprus
Christina Oikonomou
Frederick University, Cyprus
Recent Global Research Developments in Tonga Volcanic Eruption
Modeling the 2022 Tonga Eruption Tsunami Recorded on Ocean Bottom Pressure and Tide Gauges Around the Pacific:
- Tsunamis generated by the Hunga Tonga–Hunga Ha’apai volcanic eruption on January 15, 2022, were recorded on ocean bottom pressure and tide gauges around the Pacific Ocean. These tsunamis arrived earlier than expected based on calculated tsunami propagation speeds.
- Atmospheric waves from the eruption were also recorded globally, with propagation speeds of approximately 310 m/s (Lamb wave) and 200–250 m/s (Pekeris wave).
- The study simulated the tsunamis generated by the propagation of these atmospheric waves, providing insights into their behavior and impact [1].
New study suggests the trigger of Tonga’s volcanic eruption:
Seismic Phenomena Associated with the Eruption of the Volcano in the Tonga Islands:
Variations in Geophysical Fields during the Tonga Volcanic Eruption:
Volcanoes and Climate: Sizing up the Impact of the Recent Hunga Tonga-Hunga Ha’apai Eruption:
References
- Fujii, Y., Satake, K. Modeling the 2022 Tonga Eruption Tsunami Recorded on Ocean Bottom Pressure and Tide Gauges Around the Pacific. Pure Appl. Geophys. (2024). https://doi.org/10.1007/s00024-024-03477-1
- New study suggests the trigger of Tonga’s volcanic eruptionhttps://www.rnz.co.nz/international/programmes/datelinepacific/audio/2018936401/new-study-suggests-the-trigger-of-tonga-s-volcanic-eruption
- Ovtchinnikov, V.M., Usoltseva, O.A. Seismic Phenomena Associated with the Eruption of the Volcano in the Region of the Tonga Archipelago on January 15, 2022. Izv., Phys. Solid Earth 59, 433–443 (2023). https://doi.org/10.1134/S1069351323030096
- Gorbunova, E.M., Ryakhovskiy, I.A., Gavrilov, B.G. et al. Variations in Geophysical Fields during the Tonga Volcanic Eruption According to the Data of the Mikhnevo Large-Scale Research Facility. Izv. Atmos. Ocean. Phys. 58, 1350–1366 (2022). https://doi.org/10.1134/S0001433822110044
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