Global Ionospheric Map : A Part from the Book Chapter : Estimation of foF2 Using Global Model of Ionospheric Slab Thickness (GMIST) During January 15, 2022 Tonga Eruption


Gerzen et al. have used Neustrelitz global TEC model (NTCM-GL) to simulate TEC and the Neustrelitz Peak Density Model (NPDM) to generate NmF2. Based on these two ionospheric parameters, they model ionospheric slab thickness. Then, ionospheric slab thick ness model was employed for NmF2 estimation from operational GNSS global TEC model. Validation of the NmF2 reconstruction from GNSS TEC model shows that both the model and the reconstruction approach produce improved results, however, the reconstruction has a factor of 1.75 better mean value during low to middle solar activity period. Still, NmF2 reconstruction has not been validated during an ionospheric storm. Muslim has developed a global model of ionospheric slab thickness (GMIST) by using global ionospheric map (GIM) model and measured foF2 ionosonde values.

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

Also See : The morphostratigraphic study: A Part from the Book Chapter : Retreat of the Shoreline in the Gulf of Castellammare di Stabia (Gulf of Napoli, Southern Italy)

Recent Global Research Developments in GMIST Estimation of foF2 During Tonga Eruption (Jan 15, 2022)

Ionospheric Perturbations: The eruption released enormous energy, affecting the ionosphere over the Pacific Rim. Researchers analyzed ionospheric disturbances using global positioning system (GPS) observations at different distances:

  • Near-Field: Perturbations occurred within 8–15 minutes after the eruption and were mainly due to shock waves generated by the blast.
  • Regional and Far-Field: Longer-distance perturbations were associated with atmospheric Lamb waves.

Total Electron Content (TEC): The amplitude of disturbance correlated with background TEC. TEC perturbations were not visible on reference days.

Source Location: Ray tracing confirmed that the Tonga event triggered an ionospheric anomaly beyond the crater.

Meteotsunami Connection: The frequency change in perturbations coincided with the initial tsunami arrival, suggesting meteotsunami generation.


  1. Li, J., Chen, K., Chai, H. et al. Ionospheric disturbance analysis of the January 15, 2022 Tonga eruption based on GPS data. Sci. China Earth Sci. 66, 1798–1813 (2023).
  2. Garza-Girón, R., Lay, T., Pollitz, F., Kanamori, H., & Rivera, L. (2023). Solid Earth–atmosphere interaction forces during the 15 January 2022 Tonga eruption. Science Advances, 9(2), eadd4931.
  3. P Heinrich, A Gailler, A Dupont, V Rey, H Hébert, C Listowski, Observations and simulations of the meteotsunami generated by the Tonga eruption on 15 January 2022 in the Mediterranean Sea, Geophysical Journal International, Volume 234, Issue 2, August 2023, Pages 903–914,
  4. Kosuke Heki, Atmospheric resonant oscillations by the 2022 January 15 eruption of the Hunga Tonga–Hunga Ha’apai volcano from GNSS-TEC observations, Geophysical Journal International, Volume 236, Issue 3, March 2024, Pages 1840–1847,

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